Australian Mammals: Biology and Captive Management

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AUSTRALIAN MAMMALS BIOLOGY AND CAPTIVE MANAGEMENT

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AUSTRALIAN MAMMALS BIOLOGY AND CAPTIVE MANAGEMENT

Stephen Jackson

© CSIRO 2003 All rights reserved. Except under the conditions described in the Australian Copyright Act 1968 and subsequent amendments, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, duplicating or otherwise, without the prior permission of the copyright owner. Contact CSIRO PUBLISHING for all permission requests. National Library of Australia Cataloguing-in-Publication entry Jackson, Stephen M. Australian mammals: Biology and captive management Bibliography. ISBN 0 643 06635 7. 1. Mammals – Australia. 2. Captive mammals. I. Title. 599.0994 Available from CSIRO PUBLISHING 150 Oxford Street (PO Box 1139) Collingwood VIC 3066 Australia Telephone: Local call: Fax: Email: Web site:

+61 3 9662 7666 1300 788 000 (Australia only) +61 3 9662 7555 [email protected] www.publish.csiro.au

Cover photos courtesy Stephen Jackson, Esther Beaton and Nick Alexander Set in Minion and Optima Cover and text design by James Kelly Typeset by Desktop Concepts Pty Ltd Printed in Australia by Ligare

CONTENTS

Foreword

xvii

Introduction

xix

Acknowledgments

xxi

Outline

xxii

6.2 6.3 6.4

7

1 Platypus 1 Introduction

1

2 Taxonomy 2.1 Nomenclature 2.2 Subspecies 2.3 Recent synonyms 2.4 Other common names

2 2 2 2 2

3 Natural history 3.1 Morphometrics 3.2 Distribution and habitat 3.3 Conservation status 3.4 Diet in the wild 3.5 Longevity

2 2 2 2 2 3

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Nest boxes 4.9 Enclosure furnishings

3 3 5 5 6 6 6 6 6 6

5 General husbandry 5.1 Hygiene and cleaning 5.2 Record keeping 5.3 Methods of identification

6 6 7 8

6 Feeding requirements 6.1 Captive diet

8 8

8

9

10

Supplements Presentation of food Estimating the amount of food consumed Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements Health requirements 8.1 Daily health checks 8.2 Detailed physical examination 8.3 Known health problems Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Grooming 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 Interspecific compatibility 9.11 Suitability to captivity Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nesting requirements

9 9 9 9 9 9 10 11 11 11 11 11 12 12 15 15 15 15 15 15 16 17 17 17 19 19 19 19 19 19 20 20 20 20 20 20 20

vi

Contents

10.11 Breeding diet 10.12 Oestrous cycle and gestation and incubation periods 10.13 Litter size 10.14 Age at weaning 10.15 Age at removal from parent 10.16 Growth and development

21 21 21 22 22

11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures

22 22 23 24 25 25 26 26 26 26 26 27

12 Acknowledgments Addendum 1 Introducing platypus to unfamiliar facilities and/or other platypus Addendum 2 Bringing platypus in from the wild Addendum 3 Rescued platypus

27

2

21

28 28 30

Echidnas

1 Introduction

33


34 34 34 34 34


34 34 34 34 34 34

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection

34 34 35 35 35 35

4.6 4.7 4.8 4.9

Temperature requirements Substrate Nest boxes Enclosure furnishings

35 35 35 35


36 36 36 36

6 Feeding requirements 6.1 Captive diet 6.2 Supplements 6.3 Presentation of food

36 36 37 37

7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements

37 37 37 37 38 39 39

8 Health requirements 8.1 Daily health checks 8.2 Detailed physical examination 8.3 Known health problems

39 39 39 40

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 Interspecific compatibility

42 42 43 43 43 43 43 43 44 44 44

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first breeding and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nest/hollow requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation and incubation periods

44 44 44 44 45 45 45 46 46 46 46 46 46

Contents

Litter size Age at weaning Age of removal from parents Growth and development

46 46 46 46


64 64 68 68

11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene and special precautions 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures

47 47 47 48 49 49 50 50 50 50 50 51


68 68 68 68 70 71 71


71 71 72 72

12 Acknowledgments

51


74 74 75 78 79 79 79 79 80 80 80

10.13 10.14 10.15 10.16

3

Carnivorous marsupials

1 Introduction

53


55 55 55 55 55


55 55 55 55 55 57


59 59 59 61 61 61 61 62 62 62


63 63 63 63

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first breeding and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nesting requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age at removal from parent 10.16 Growth and development

81 81 83 84 86 88 88 89 89 89 89 89 92 92 92 92 93

11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements

93 93 94 95 95

vii

viii

Contents

11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures 12 Acknowledgments

4

96 96 96 96 97 97 97 97

Numbats

1 Introduction

99

2 Taxonomy 2.1 Nomenclature 2.2 Subspecies 2.3 Recent synonyms 2.4 Other common names 3 Natural history 3.1 Morphometrics 3.2 Distribution and habitat 3.3 Conservation status 3.4 Diet in the wild 3.5 Longevity 4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Nest boxes 4.9 Enclosure furnishings

100 100 100 100 100 100 100 100 100 100 101 101 101 102 103 103 103 103 104 104 104

5 General husbandry 5.1 Hygiene and cleaning 5.2 Record keeping 5.3 Methods of identification 6 Feeding requirements 6.1 Captive diet 6.2 Supplements 6.3 Presentation of food 7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements

105 105 105 105 105 105 106 107 107 107 107 107 108 108 108


108 108 109 109


111 111 111 111 112 112 112 112 112 112 113

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first breeding and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nest/hollow requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age of removal from parents 10.16 Growth and development

113 113 113 113 114 115 115 115 115 115 115 115 115 115 115 115 115

11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster mothers 11.10 Weaning 11.11 Rehabilitation and release procedures

116 116 116 116 118 118 118 118 119 119 119 119

12 Acknowledgments Addendum 1 Sustainable termite harvesting techniques Addendum 2 Artificial diet preparation of egg custard

119 120 124

Contents

Addendum 3 Example of 100% termite diet prior to breeding season (November–March) in numbats

5

125

Bandicoots

1 Introduction

127


128 128 128 128 128

3 Natural history 3.1 Morphometrics 3.2 Distribution and habitat 3.3 Conservation status 3.4 Diet in the wild 3.5 Longevity 4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Nest boxes 4.9 Enclosure furnishings 5 General husbandry 5.1 Hygiene and cleaning 5.2 Record keeping 5.3 Methods of identification 6 Feeding requirements 6.1 Captive diet 6.2 Supplements 6.3 Presentation of food 7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements 8 Health requirements 8.1 Daily health checks 8.2 Detailed physical examination 8.3 Known health problems

128 128 128 128 128 128 129 129 129 129 130 130 130 130 130 130 130 130 130 131 131 131 132 132 132 132 132 132 133 133 133 134 134 134 135


136 136 136 137 137 137 137 137 137 138 138

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first breeding and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nest/hollow requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age of removal from parents 10.16 Growth and development

138 138 138 138 139 139 139 139 140 140 140 140 140 140 141 141 141


141 141 141 143 143 143 143 143 144 144 144 144

12 Acknowledgments

144

6

Koalas

1 Introduction

145

2 Taxonomy 2.1 Nomenclature 2.2 Subspecies

147 147 147

ix

x

Contents

2.3 2.4

Recent synonyms Other common names

147 147


147 147 148 148 149 149

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Enclosure furnishings

150 150 151 152 152 152 152 152 153


153 153 154 154


154 154 158 158

7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements 7.7 Koala handling and photographing by the public

159 159 159 159 160 160 160

8 Health requirements 8.1 Daily health checks 8.2 Detailed physical examination 8.3 Known health problems 8.4 Chlamydia control

161 161 162 163 166

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility

167 167 168 168 168 168 168 169 169 169

9.10 Interspecific compatibility 10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nesting requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age at removal from parent 10.16 Growth and development

169 169 169 169 169 170 171 171 171 171 171 171 171 171 171 172 172 172


173 173 174 174 176 177 177 177 178 178 178 178

12 Acknowledgments

178

Addendum 1 The management of eucalyptus plantations for koala fodder

179

161

7

Wombats

1 Introduction

183

2 Taxonomy 2.1 Nomenclature 2.2 Subspecies 2.3 Recent synonyms 2.4 Other common names 3 Natural history 3.1 Morphometrics 3.2 Distribution and habitat 3.3 Conservation status 3.4 Diet in the wild 3.5 Longevity

184 184 184 184 184 184 184 184 184 184 185

Contents


185 185 186 186 186 186 186 186 187 187


187 187 187 187


188 188 188 188


188 188 188 188 189 189 189


190 190 190 191

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 Interspecific compatibility 9.11 Suitability to captivity

193 193 194 195 195 195 195 196 196 196 196 196

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive condition 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first breeding and last breeding

196 196 197 197 197 197 198 198

10.8 10.9 10.10 10.11 10.12 10.13 10.14 10.15 10.16

Ability to breed every year Ability to breed more than once per year Nesting requirements Breeding diet Oestrous cycle and gestation period Litter size Age at weaning Age of removal from parents Growth and development

198 198 198 198 199 199 199 199 199


200 200 200 200 201 202 202 202 202 203 203 203

12 Acknowledgments

203

8

Possums and gliders

1 Introduction

205


206 206 206 206 206


206 206 206 206 206 209


210 210 214 214 214 214 215 215 215 215

xi

xii

Contents


215 215 216 217


217 217 221 221


221 221 221 221 223 223 223


224 224 224 225

9 Behaviour 9.1 Activity cycles 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 Interspecific compatibility

227 227 229 232 232 232 232 232 232 232 233

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive status 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Nesting requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age at removal from parent 10.16 Growth and development

234 234 234 235 236 236 236 236 236 236 236 238 238 238 238 238 238

11 Artificial rearing 11.1 Housing

238 238

11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures 12 Acknowledgments

9

239 240 242 242 242 242 243 243 243 244 244

Macropods

1 Introduction

245


246 246 246 246 246

3 Natural history 3.1 Morphometrics 3.2 Distribution and habitat 3.3 Conservation status 3.4 Diet in the wild 3.5 Longevity 4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Enclosure furnishings 5 General husbandry 5.1 Hygiene and cleaning 5.2 Record keeping 5.3 Methods of identification 6 Feeding requirements 6.1 Captive diet 6.2 Supplements 6.3 Presentation of food 7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags 7.3 Capture and restraint techniques 7.4 Weighing and examination

246 246 246 246 246 246 251 251 256 256 256 257 257 257 257 257 257 258 258 259 259 262 262 262 262 262 262 267

Contents

7.5 7.6

Release Transport requirements

267 267


268 268 269 270


276 276 277 279 279 279 280 280 280 280 281

10 Breeding 281 10.1 Mating system 281 10.2 Ease of breeding 281 10.3 Reproductive status 282 10.4 Techniques used to control breeding 284 10.5 Occurrence of hybrids 284 10.6 Timing of breeding 284 10.7 Age at first and last breeding 286 10.8 Ability to breed every year 286 10.9 Ability to breed more than once per year 286 10.10 Nesting requirements 286 10.11 Breeding diet 286 10.12 Oestrous cycle and gestation period 286 10.13 Litter size 286 10.14 Age at weaning 288 10.15 Age at removal from parent 288 10.16 Growth and development 289 11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures

289 289 289 289 292 293 293 293 294 294 295 295

12 Acknowledgments

295

10

Bats

1 Introduction

297


298 298 298 298 298


298 298 298 298 298 298

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Roosting boxes 4.9 Enclosure furnishings

303 303 306 306 307 307 307 309 310 311


311 311 313 313


316 316 320 320

7 Handling and transport 7.1 Timing of capture and handling 7.2 Catching bags and other containment devices 7.3 Capture and restraint techniques 7.4 Weighing and examination 7.5 Release 7.6 Transport requirements

321 321


326 326 327 327

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour

331 331 333 333

321 322 325 325 325

xiii

xiv

Contents

9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11

Bathing Behavioural problems Signs of stress Behavioural enrichment Introductions and removals Intraspecific compatibility Interspecific compatibility Suitability to captivity

333 333 334 334 334 334 334 335

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive condition 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Roosting requirements 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size 10.14 Age at weaning 10.15 Age at removal from parents 10.16 Growth and development

336 336 336 337 338 338 338 341 341 341 341 341 341 341 341 341 342


342 342 345 345 348 348 349 349 349 349 349 350

12 Acknowledgments

350

11

Rodents

1 Introduction

351


352 352 352 352 352


352 352 352 352 352 352

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements 4.7 Substrate 4.8 Nest sites 4.9 Enclosure furnishings

354 354 355 356 356 356 356 356 356 357


357 357 357 358


358 358 359 359


360 360 360 360 361 361 361


361 361 361 362

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 interspecific compatibility

363 363 364 367 367 367 367 367 367 368 368

10 Breeding 10.1 Mating system 10.2 Ease of breeding

368 368 369

Contents

10.3 10.4 10.5 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13 10.14 10.15 10.16

Reproductive condition Techniques used to control breeding Occurrence of hybrids Timing of breeding Age at first and last breeding Ability to breed every year Ability to breed more than once per year Nest/hollow requirements Breeding diet Oestrous cycle and gestation period Litter size Age at weaning Age at removal from parents Growth and development

369 371 371 373 373 373 373 373 373 373 375 375 375 375


375 375 376 376 377 379 379 379 379 379 379 380

12 Acknowledgments

380

12

Dingoes

1 Introduction

381


382 382 382 382 382


382 382 382 382 382 382

4 Housing requirements 4.1 Exhibit design 4.2 Holding area design 4.3 Spatial requirements 4.4 Position of enclosures 4.5 Weather protection 4.6 Temperature requirements

383 383 384 384 385 385 385

4.7 4.8 4.9

Substrate Shelter Enclosure furnishings

385 385 385


385 385 385 385


386 386 386 386


387 387 387 387 387 387 387


388 388 388 389

9 Behaviour 9.1 Activity 9.2 Social behaviour 9.3 Reproductive behaviour 9.4 Bathing 9.5 Behavioural problems 9.6 Signs of stress 9.7 Behavioural enrichment 9.8 Introductions and removals 9.9 Intraspecific compatibility 9.10 Interspecific compatibility 9.11 Socialisation 9.12 Training

394 394 395 397 397 397 397 397 398 398 398 398 399

10 Breeding 10.1 Mating system 10.2 Ease of breeding 10.3 Reproductive condition 10.4 Techniques used to control breeding 10.5 Occurrence of hybrids 10.6 Timing of breeding 10.7 Age at first and last breeding 10.8 Ability to breed every year 10.9 Ability to breed more than once per year 10.10 Whelping dens 10.11 Breeding diet 10.12 Oestrous cycle and gestation period 10.13 Litter size

399 399 399 400 400 400 402 402 403 403 403 403 403 403

xv

xvi

Contents

10.14 Age at weaning 10.15 Age at removal from parents 10.16 Growth and development 11 Artificial rearing 11.1 Housing 11.2 Temperature requirements 11.3 Diet and feeding routine 11.4 Specific requirements 11.5 Data recording 11.6 Identification methods 11.7 Hygiene 11.8 Behavioural considerations 11.9 Use of foster species 11.10 Weaning 11.11 Rehabilitation and release procedures

403 403 404 404 404 404 404 405 405 406 406 406 406 406 407

12 Acknowledgments References Appendix 1 – Glossary Appendix 2 – Enclosure sizes Appendix 3 – Suppliers and Wildlife Agencies Appendix 4 – Marsupial milk, milk formulas and comparison with monotreme and eutherian milk Appendix 5 – Taking body measurements Appendix 6 – General references Bibliography

407 408 468 473 476

482 487 488 491

FOREWORD

As someone who has had more than twelve years experience within the zoo profession, it is with great pleasure that I pen these few words as a foreword to this excellent publication. As it says in the Introduction, there have been many previous books and publications on the subject of managing Australian animals in captivity. It is my belief that this current publication will prove to be a landmark publication and the reference for all those interested in maintaining animals in captivity. It matters not whether you are a zoo professional, research institution, wildlife carer, National Parks personnel or an enthusiastic amateur – this book is for you. The book itself gives a most useful brief account of the historic record of each group in captivity before moving on to cover subjects including husbandry, diet, captive breeding, conservation status, milk supplements and replacements and recommendations for display and behavioural enrichment. As I perused the various chapters, I was struck by the speed with which our knowledge of these animals is increasing and the need to centralise it in one publication. I was also struck by the fact that we have come a long way since Captain Nicolas Baudin, on his way back to Europe in 1803, fed his kangaroos wine and sugar, while the emus were force fed with pellets of rice mash and his officers gave up their cabins to accommodate the animals. The fact that so many survived this long voyage says more about the hardiness of the animals than the dietary knowledge of their carers. Since the first specimens were taken back to Europe at the end of the 18th century, Australian animals, owing to their uniqueness, have held a fascination for people throughout the world. That the fascination has not abated, but indeed increased, is evidenced by the number of institutions throughout the world which are displaying a number of species and those which are asking to be allowed to display some of our unique fauna. The original reasons for taking animals to the northern hemisphere was certainly to demonstrate our dominion over nature and to show these ‘curiosities’ to the public. Today, while curiosity and fascination still play a part in the desire to display Australian animals, more and more often the animals are being used for conservation education reasons and, on occasions, captive breeding. It is unfortunate that Australia has had an unenviable record in species extinction during our first 150 years of settlement. It behoves us to maintain what we have left and to increase the numbers existing, both in the field and by captive management, of a number of species. Success is best achieved by increasing our knowledge of our fauna and undertaking public education programs. I am, of course, committed to the roles which zoos and like institutions can play in ensuring that conservation breeding, research and conservation education programs are undertaken. This book contains the work and knowledge of a large number of experts and professionals, many of whom I have come to know personally over the years. I believe that it will become a ‘must have’ volume on the library shelves of people seriously interested in the future of Australian mammals. I commend Stephen Jackson, CSIRO Publishing and all those involved in this excellent undertaking and I commend the book to you, the reader. Ed McAlister AO President World Association of Zoos and Aquariums Adelaide November 2003


INTRODUCTION

Australian mammals have been held in captivity in Australia and throughout the world for over 200 years. Although originally kept as sources of curiosity, entertainment and novelty, today they are increasingly held to educate the public about their biology and threatened status, as part of captive breeding programs, for hand-rearing following the death of their mothers, for rehabilitation after injury or illness, for research and as pets. Captive facilities need to optimize conditions for the animals by allowing them to feel secure, providing high quality food, allowing them to undertake a large range of natural solitary and social behaviours, allowing them to be easily observed for husbandry and education purposes and allowing the animals to be caught with minimum stress. The husbandry of Australia’s mammals in captivity is an expanding field, with earlier literature based largely on first-hand experiences of enclosure sizes, captive diet, behaviour and breeding. While this information is highly valuable, there has been a need to bring together aspects of the biology (including wild diet, social behaviour, reproduction and nesting requirements) to maximize appropriate conditions for these species in captivity. Publications such as the landmark Monotremes and Marsupials (Collins 1973), The Management of Australian Mammals in Captivity (Evans 1982) and more recently the Care and Handling of Australian Native Animals (Hand 1990) have made great advances in our knowledge of the husbandry of Australian mammals, though they do not include all mammalian taxonomic groups nor attempt to match the general principles of husbandry with their wild biology and, with the exception of Collins (1973), nor do they have a standardized outline for information coverage.

The aim of this book is to provide detailed information on the biology and husbandry of all Australia’s native terrestrial mammals. It is hoped that zookeepers, students, researchers, veterinarians, wildlife carers and the ever-expanding group of private individuals that keep Australian mammals as pets will find the information on general biology, captive management, behaviour, breeding, the extensive reference list and bibliography, useful. Although primarily focused on the management of Australian mammals in captivity, various aspects are of use to field biologists including capture and restraint techniques, aging techniques and behaviour and breeding information. It is also hoped that this volume will stimulate further improvement in the standard of husbandry of Australian mammals. Despite attempts to incorporate as much published and unpublished information as possible in this book, there are clearly numerous gaps in our knowledge that need to be filled. Areas of future development include fine-tuning diets, enclosure designs, area requirements, capture and restraint techniques, behavioral enrichment methods and population management techniques. The availability of animals within captive facilities also allows the opportunity to undertake significant research including studies on taxonomy, aging techniques, digestive physiology, social and reproductive behaviour, reproductive physiology such as oestrous cycles and gestation periods, artificial reproductive techniques, milk composition and growth and development. With this in mind, this book is seen as the consolidation of information for the start of a journey rather than an end, and so readers are encouraged to further explore and record their knowledge of the captive management of Australian mammals.


ACKNOWLEDGMENTS

Clearly a work of this scope cannot be created in isolation, and the help and assistance of numerous people in various institutions throughout Australia and overseas has been extensively utilized. In undertaking this project I have endeavoured to include the extraordinary knowledge that exists within the zoo industry and by numerous field biologists, by asking many people to read and make comments on various draft chapters or sections of chapters in order to improve them further. This information has proved invaluable in making this work of greater quality and giving a broader perspective than a particular institution and therefore is more widely useful. Although I have been responsible for putting the book together, the end product is a testament to the abundant skills and experience, generously shared, by people within the zoo industry and numerous biologists. In particular I would like to thank those who coauthored or authored several of the chapters including Dr Melody Serena, Dr David Middleton, Vicki Power, Dr Cree Monaghan, Dr Katie Reid, Des Spittal and Liz Romer. Sincere thanks to Lindell Andrews, Wendy Gleen, Annette Gifford and Geoff Underwood for reviewing many of the chapters. I am very grateful to Annette Gifford, Jo Cowey and Louise Baume who reviewed the sections on artificial rearing and made numerous valuable suggestions. Professor Peter Temple-Smith and Dr David Taggart reviewed the sections on reproduction and several other chapters, which was greatly appreciated. Dr Michael Messer made

numerous valuable comments on the content of milk of the various taxonomic groups and the use of various milk formulas. An enormous thankyou goes to the various veterinarians who read over the health requirements section of each chapter and made various suggestions to ensure the health information was accurate, including Dr Terri Bellamy, Dr David Blyde, Dr Rosie Booth, Dr Cree Monaghan, Dr Lee Skerratt and Dr Rupert Woods. Dr Ian Lugdon also read over all the health sections and made numerous valuable comments. Many thanks to the staff at Taronga Zoo who read over various drafts of most chapters and allowed me to take photos from which most of the handling drawings were completed. The staff of the Zoological Parks and Gardens Board of Victoria, including Michael de Oleveira, Professor Peter Temple-Smith and Gary Slater provided valuable support for this project. I am also grateful for the assistance of Megan Temple who photocopied a number of the references. Acknowledgments for individuals who helped in the different chapters can be found at the end of each chapter. Thanks also to those who helped review the whole document including William Meikle and Matthew Crane. Many thanks also to Nick Alexander and Briana Elwood from CSIRO Publishing for all their hard work and patience in putting this work together. Finally many thanks also to my parents and Kerstin McPherson for her patience and encouragement in writing this and for her assistance in finding many references.

OUTLINE

Each chapter covers a separate taxonomic group of Australian mammals and an effort has been made to make the scope of information covered as uniform as possible by using the husbandry manual outline described in Jackson (2003). The common names and

taxonomy used in this book follows Strahan (1995) except where stated. The references for each chapter are found in the reference section at the end of the book with additional references that may be useful being found in the bibliography.

1 PLATYPUS

Stephen Jackson, Melody Serena and David Middleton

1. Introduction The platypus and the echidnas, that make up the Australian monotremes, are unique mammals due to their egg laying, appearance and lifestyles and are of enormous community and scientific interest. In particular, the unique features and secretive lifestyle of the platypus have made it a longstanding focus of attention. Platypus appear to have been first held in captivity by Maule (1832) in 1831 who captured a female and two young that lived for two weeks on worms, bread and milk. In 1832 and 1833 Bennett (1834a, 1834b) held several animals including two young that survived five weeks on bread soaked in water, chopped egg and finely minced meat. Subsequently, platypus were held by Verreaux (1848) who fed them a diet of rice and egg yolk, while Burrell (1927) was the first person to display them to the Australian public – in 1910 for three months at the Sydney Zoological Gardens when it was at Moore Park (prior to its move where it became Taronga Zoo). Budapest Zoo was the first overseas zoo to receive a live animal in 1913 when two animals were sent there (Collins 1973). In 1922 an animal was transferred to New York Zoological Park where it lived for 49 days and was on display for one hour per day (Joseph 1922; Burrell 1927). The only other platypus sent overseas was in 1947 and 1958 when a male and two females were sent (on each occasion) to the New York Zoological Society (Fleay 1980). Early attempts to keep platypus in captivity resulted in them dying after only a few weeks or months, and it was not until 1932 that the first long-term maintenance and display of platypus occurred at Healesville Sanctuary, Victoria, Australia when an animal was kept for several years (Eadie 1935). Little effort was spent attempting to breed platypus until the success of Fleay (1944) in the summer of 1943/44 at Healesville Sanctuary. Although platypus have been maintained for extended periods in a number of institutions in recent years, in a truly captive environment, successful breeding resulting in live young is very rare. Since platypus first came into captivity until the end of 2002/2003 breeding season, captive platypus have only been bred successfully on three other occasions (Holland and Jackson 2002; A. Battaglia and M. Hawkins pers. comm.; pers. obs.). Today only seven Australian zoos maintain platypus (Lees and Johnson 2002; pers. obs.). Platypus exhibits and management of the species follow similar lines in institutions across Australia, however, new approaches are continually being developed and used as more information on platypus husbandry and biology becomes available. Captive management of platypus has an essential role to play in biological research as well as conservation-based educational displays. At the same time, the perceived poor survival of captive platypus has generated concern amongst managers, researchers, conservationists and the general community. Accordingly, there is a need to ensure that impeccable standards for captive management of platypus are developed. Whilst many standards may be universally applicable it would be false to say that we have the definitive ‘recipe’ for exhibiting, maintaining and breeding platypus in captivity.

2

Australian Mammals: Biology and Captive Management

2. Taxonomy

being found in Queensland and the largest ones in New South Wales west of the Divide and in Tasmania (Carrick 1995; Connolly and Obendorf 1998). Length is measured from tip of bill to tip of tail (Carrick 1995) (Table 1). There is a distinct sexual dimorphism with males being larger and heavier than females. The platypus is easily distinguished from all other mammals by its soft flexible bill, webbed feet and aquatic lifestyle.

2.1 Nomenclature The platypus was originally described as Platypus anatinus by Shaw (1799). However as that name was already used for a genus of beetles, the term Ornithorhynchus was used. This is the name used by Blumenbach (1800) to describe the platypus when he called it Ornithorhynchus paradoxus. Class: Mammalia Subclass: Prototheria Order: Monotremata Family: Ornithorhynchidae Genus species: Ornithorhynchus anatinus Etymology Ornithorhynchus – bird snout anatinus – duck like Platypus – flat foot

3.2 Distribution and habitat The platypus occurs in freshwater streams along the east coast of Australia from north Queensland to South Australia (including Kangaroo Island, where they were introduced) and Tasmania (including King Island) and in streams running westward from the Great Dividing Range (Fig. 1). It is also found in occasionally brackish streams, creeks, lakes and ponds. These vary from shallow creeks with pools and riffles to large deep rivers. When out of the water, platypus live in burrows that are dug into the bank of the water body. Burrows are usually short and simple in construction with the entrance either above or below the water level, and often under a tangle of tree roots (Carrick 1995).

2.2 Subspecies None

2.3 Recent synonyms Synonyms of the platypus can be found in Mahoney (1988).

3.3 Conservation status

2.4 Other common names

Throughout its distribution the platypus is relatively common and considered to be at low risk of extinction.

In the past it has been called a water mole.

3.4 Diet in the wild

3. Natural history

In the wild, platypus feed on a wide variety of freshwater adult and larval invertebrates including dragonflies and caddisflies (Table 2). The platypus has a complex bill apparatus that it uses to sift smaller prey items. Platypus appear to find their food by detecting the weak electrical impulses of invertebrates when they move their exoskeletons. Once food is picked up and sifted, it is stored in cheek pouches, and is then thoroughly masticated while the animal floats on the surface of the water.

3.1 Morphometrics The platypus is one of Australia’s most easily recognisable animals. It is approximately 40–50 cm long, has a dense waterproof fur over all of its body except the bill and feet, and a bill that is soft and pliable. It has webbed feet and the males possess a venomous spur on the inside of their hind legs. Size varies with location, with a general north to south cline variation in body size, the smallest animals

Table 1. Body length and weight for different locations in Australia. Location North Queensland South-east Queensland New South Wales – East of Divide New South Wales – On Divide New South Wales – West of Divide Tasmania From Carrick (1995)

Total Length (cm) Males 44.1 ± 3.1 49.3 ± 2.7 50.5 ± 2.4 47.4 ± 3.5 54.9 ± 29 53.2

Females 41.0 ± 1.8 43.8 ± 1.6 41.5 ± 2.0 40.3 ± 2.0 47.0 53.5

Weight (g) Males 1018 ± 208 1556 ± 194 1434 ± 218 1379 ±132 2215 ± 364 1900 ±

Females 704 ± 49 1222 ± 94 857 ± 107 888 ± 92 2000 1500

Platypus

3.5.3 Techniques to determine the age of adults Platypus are difficult to age once they have achieved the adult body weight. In males the spurs show wear which can be used to estimate age (Fig. 2). Females 8–10 months of age have a very small spur, about 1–2 mm long that is whitish or brownish. Older than that, they usually do not have a spur (Grant 1995).

Figure 1. Distribution of the platypus. After Grant (1995) with permission of UNSW Press.

3.5 Longevity 3.5.1 Wild Capture information from the Shoalhaven River has shown that a female who was captured as an adult was at least 15 years old and one captured as a juvenile is at least 16 years old. Four males in the population that were captured as adults were over six years of age and another animal was captured as a juvenile seven years ago (T. Grant pers. comm.). 3.5.2 Captivity In captivity platypus have been known to live for very long periods. Lone Pine Koala Sanctuary has held an animal to 21 years of age, while the Australian Reptile Park had an animal which lived to 18 years of age and Healesville Sanctuary had one live to 17 years of age; David Fleay’s Fauna Park and Taronga Zoo have both had animals live over 15 years. Table 2. Food of the platypus in the wild, from a study at the upper Shoalhaven River, NSW. Food

% in Winter

Horsehair worms

17

Freshwater shrimps

12

% in Summer

spur

outer horny shell

inner fibrous layer

surrounding epidermal mass a

b

c

d

e

f

epidermal collar

Figure 2. Male spur morphology changes and aging in male platypus. Derived from Temple-Smith (1973, pers. comm.) and Grant (1995) with permission of UNSW Press.

Caddisfly larvae

41

64

Two winged larvae

12

18

Mayfly larvae

18

Stonefly larvae

9

Dragonfly larvae

9

From Grant (1995)

Sex/Age Class Using Spur Development (Fig. 2) a Juvenile 1

Restricted

Seasonal

11

26

Pseudantechinus woolleyae

Mono

>1

Restricted

Seasonal

11

27

Sarcophilus harrisii

Mono

>1

Restricted

Seasonal

48

28,29,30,31,32

Sminthopsis griseoventer

Mono

>1

Restricted

Seasonal

11

33

Dasycercus cristicauda

Fac. Poly

>1

Restricted

Seasonal

11

35,34,36,37,38

Dasyurus geoffroii

Fac. Poly

>1

Restricted

Seasonal

11

39,40,41

Dasyurus maculatus

Fac. Poly

>1

Restricted

Seasonal

11

42,43

Dasyurus viverrinus

Fac. Poly

>1

Restricted

Seasonal

11

29,44,45,46,47

Sminthopsis leucopus

Fac. Poly

>1

Restricted

Seasonal

11

48,49,50

?

?

Extended

?

?

6

Sminthopsis crassicaudata

Poly

>1

Extended

Seasonal

6

14,51,52

Sminthopsis dolichura

Poly

>1

Extended

Seasonal

6

53

Sminthopsis douglasi

Poly

>1

Extended

Seasonal

6

6,27

Sminthopsis gilberti

Poly

>1

Extended

Seasonal

?

6,27

Sminthopsis macroura

Poly

>1

Extended

Seasonal

6

54

Sminthopsis murina

Poly

>1

Extended

Seasonal

6

55

Sminthopsis v. nitela

Poly

>1

Extended

Seasonal

6

6,56

Dasycercus byrnei

Poly

>1

Extended

Seasonal

8–11

14,57,58,59

Planigale gilesi

Poly

>1

Extended

Seasonal

8–11

60,61,62

Planigale ingrami

Poly

>1

Extended

Seasonal

8–11

27,63,64,65,66

Planigale m. maculata

Poly

>1

Extended

Seasonal

8–11

66,67,68,69

Planigale tenuirostris

Poly

>1

Extended

Seasonal

8–11

60,62,70

Ningaui ridei

Poly

>1

Extended

Seasonal

8–11

38,71,72

Ningaui timealeyi

Poly

>1

Extended

Seasonal

8–11

6,72

Ningaui yvonneae

Poly

>1

Extended

Seasonal

8–11

6,27,72

Antechinomys laniger

Poly

>1

Extended

Seasonal

8–11

5,14,73

Sminthopsis ooldea

Poly

>1

Extended

Seasonal

8–11

74

Sminthopsis bindi

References


Table 9. Life history traits of dasyurid marsupials; species in which some populations can exhibit more than one life history trait. (Continued) Strategy

6

Species

Oestrous

Seasons per male

Duration of Breeding

Seasonality

Maturity (months)

References

Sminthopsis longicaudata

Poly

>1

Extended

Seasonal

8–11

Sminthopsis psammophila

?

?

Extended

?

?

6

Sminthopsis youngsoni

?

?

Extended

Seasonal

?

6,38

Planigale m. sinualis

Poly

>1

Extended

Aseasonal

?

66,76,77

Sminthopsis v. virginiae

Poly

?

Extended

Aseasonal

6

6,78

75

From Lee et al. (1982) and Krajewski et al. (2000) *Some populations exhibit different strategies References: 1 Woolley 1982; 2 Woolley 1991a; 3 Dickman and Braithwaite 1992; 4 Woolley 1966; 5 Lee et al. 1982; 6 Strahan 1995; 7 Calaby and Taylor 1981; 8 Woolley 1981; 9 Fleay 1949; 10 Van Dyck 1982; 11 Van Dyck 1980; 12 Leung 1999; 13 Wainer 1976; 14 Woolley 1973; 15 Wood 1970; 16 C. Dickman pers. comm.; 17 Bradley 1997; 18 Fleay 1934; 19 Cuttle 1982b; 20 Soderquist 1993; 21 Fleay 1962; 22 Begg 1981a; 23 Woolley 1971b; 24 Begg 1981b; 25 Woolley 1991b; 26 Woolley 1988; 27 Krajewski et al. 2000; 28 Fleay 1935a; 29 Green 1967; 30 Guiler 1970; 31 Buchmann and Guiler 1977; 32 Hughes 1982; 33 Crowther et al. 1999; 34 Jones 1923; 35 Fleay 1961; 36 Michener 1969; 37 Woolley 1971a; 38 Dickman et al. 2001; 39 Arnold and Shield 1970; 40 Archer 1974; 41 Arnold 1976; 42 Fleay 1940; 43 Settle 1978; 44 Hill and Donaghue 1913; 45 Hill and Hill 1955; 46 Fletcher 1977; 47 Godsell 1982b; 48 Read et al. 1983; 49 Woolley and Ahern 1983; 50 Woolley and Gilfillan 1990; 51 Godfrey and Crowcroft 1971; 52 Morton 1978b; 53 Friend et al. 1997; 54 Godfrey 1969a; 55 Fox and Whitford 1982; 56 Morton et al. 1987; 57 Mack 1961; 58 Aslin 1974; 59 Hutson 1976; 60 Denny 1982; 61 Whitford et al. 1982; 62 Read 1984a; 63 Fleay 1965; 64 Heinsohn 1970; 65 Woolley 1974; 66 Archer 1976; 67 Morrison 1975; 68 Van Dyck 1979; 69 Denny 1982; 70 Denny et al. 1979; 71 Fanning 1982; 72 Kitchener et al. 1986; 73 Woolley 1984; 74 Aslin 1983; 75 Woolley and Valente 1986; 76 Davies 1960; 77 Taylor et al. 1982; 78 Taplin 1980.

category of life history for species exhibiting facultative male die-off (Mills and Bencini 2000). Strategy 3 is similar to Strategy 2 except that females are facultative polyoestrous and can undergo a second oestrous if unmated or if they have prematurely lost the first litter. These include eastern quolls, spotted-tailed quolls, mulgara, and the white-footed dunnart. Strategy 4, 5 and 6: These species are polyoestrous and usually produce at least two litters in a breeding season. In Strategy 4 species, the females are polyoestrous, the males are perennial, the breeding seasons are extended and maturity is attained in six months or less. Strategy 5 is similar to Strategy 4 except that maturity occurs at 8–11 months. Examples of Strategy 4 species include the fat-tailed dunnart, striped-faced dunnart and common dunnart, with Strategy 5 including ningauis, common dunnarts, planigales, kultarr, and the kowari. Strategy 6 is similar to Strategy 5 except that breeding is aseasonal with year-round reproduction. Species who use this strategy include the black-tailed antechinus, long-nosed antechinus and the common planigale. 10.1.2 Multiple paternity Multiple paternity appears to be common in dasyurids with studies on the agile antechinus, brown antechinus, brush-tailed phascogale and Tasmanian devil finding sperm competition and multiple paternity within litters (Millis 1995; Shimmin et al. 2000; M. Jones pers. comm.). The potential of species to exhibit sperm competition and therefore multiple paternity can be

estimated by examining the relative size of the testis to the body weight as those with large testis compared to their body size are likely to have higher sperm competition (Taggart et al. 1998). These results have implications for captive breeding programs as they can increase the genetic diversity of the population, though it also means that the paternity is not exactly known unless paternity tests are undertaken. One method used with good success with brush-tailed phascogales is rotation of males through the female’s enclosures twice per week during the breeding season (Halley 1992).

10.2 Ease of breeding A detailed knowledge of the lifecycle of some species is essential if successful breeding groups are to be maintained (Williams 1990). Most species are kept as pairs, until young are born, and pairing of animals is often required until a compatible pair is found (Williams 1990). Good breeding success has been achieved when the male is introduced when the female is in oestrous, which is determined by the presence of cornified epithelial cells (See Section 10.4). Mate choice trials with Tasmanian devils suggest that females show a distinct preference for one male over another. These results suggest that in every species of dasyurid a female may not like an individual male that has been put in her enclosure. Therefore, providing her with a choice may be desirable, perhaps allowing her to contact males through a fence or partition first. Although she will probably mate with the male provided, this

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technique maximizes the likelihood of successful breeding (M. Jones pers. comm.). Many of the smaller species of dasyurids have been found to be relatively easy to breed as long as they are housed with access to natural light cycles. To date, a number of species have bred and reared young successfully in captivity, including the stripe-faced dunnart, Julia Creek dunnart, yellow-footed antechinus, fat-tailed pseudantechinus, fat-tailed-dunnart, little red kaluta, brown antechinus, mulgara, kowari, southern dibbler, brush-tailed phascogale, western quoll and Tasmanian devil (Woolley 1982, pers. comm.; Bennett et al. 1990; Gaikhorst 1999; Lambert 2000). Attempts to breed the white-footed dunnart, northern dibbler, ningbing antechinus and kultarr have proved difficult (Aslin 1982; Woolley 1982). The species that have bred with the greatest success and are considered the most suitable for establishing a perpetual colony are the kowari, little red kaluta, agile antechinus, yellow-footed antechinus, fat-tailed dunnart, stripe-faced dunnart, brush-tailed phascogale, eastern quoll and western quoll (Woolley 1982; Halley 1992; Gaikhorst 1999; D. Taggart pers. comm.). The Tasmanian devil has been bred on many occasions, however it has proved difficult to breed routinely. As early as 1915 they have been considered difficult to breed in captivity (Roberts 1915; Fleay 1935a, 1952). Although many species breed successfully in captivity, the long-term viability of some populations has been problematic due to irregular breeding. Common planigales can breed rapidly in captivity initially, however success appears to decline over successive generations. Animals more than two generations from the wild generally do not breed (Aslin 1982). Similar observations have been made on the stripe-faced dunnart, where a captive population produced 109 young in the first two generations, and in the third breeding season the females had irregular oestrous cycles and in the few instances where copulation was recorded there was nearly 100% prenatal mortality. This population subsequently became extinct without the cause being definitely established (Godfrey 1969a). Even those species that have been bred successfully do not have a 100% success rate (ie every adult female in the population successfully breeds each year). Although based on small sample sizes, the success rate has been observed by Aslin (1980, 1982) to range from 14–30% for dunnarts, 12.5–33% for antechinus, 50–83% for kowaris and 50–78% for planigales. Therefore, it is important to hold a number of animals and rotate them in order to

maximize the opportunities for breeding, otherwise the entire population will die out. Some species, such as southern dibblers, breed well for one to two years, then the rate of reproduction decreases in the third year (C. Lambert pers. comm.). The incidence of cannibalism in captive bred southern dibblers can be high – they have been known to eat their entire litter (Lambert 2000). Therefore, it is important that captive-raised dibblers are exposed to minimum stress by not handling, creating visual barriers between adjacent enclosures and feeding ad lib pinkie rats and more invertebrates (Lambert 2000). Although many specimens of thylacines were held in captivity, few were held in pairs. Most were either single individuals or mothers with young. There appears to be only one record of an actual birth, which was at Melbourne Zoo in 1899 (Paddle 2000). It was suggested as early as 1907 (Le Soeuef) that thylacines do not breed in captivity.

10.3 Reproductive status 10.3.1 Females Carnivorous marsupials are generally placed in several categories depending on their reproductive status. The examination of reproductive status in small to medium sized species can be facilitated by putting them inside a transparent plastic tube and examining the pouch with an otoscope (Roberts and Kohn 1991). Small species can also be pouch checked while in a bag and exposing the pouch, or in the hand (Fig. 4.). For females these include: ■

■

■

■ ■

■

Non-parous (females that have never bred) – pouch small with no skin folds, clean and dry; teats very small. Parous (females that have bred previously but not presently) – pouch is small but distinct, dry and dirty; the teats are slightly elongated. Pregnant – pouch pink in colour and glandular in appearance; skin folds may be observed on the lateral margins of the pouch. Pouch young present – attached to the teat. Lactating (young absent from the pouch but still suckling) – pouch area large, skin folds flaccid, hair sparse and stained, skin smooth and dark pink; teats elongated. Post lactation with teats expressing only clear liquid and/or regressing.

If pouch young are present, a number of developmental stages and measurements can be recorded and compared to existing growth curves (see Section


Figure 4. Method for holding a small dasyurid to examine the pouch area. Photo by Pat Woolley.

10.16), or new curves can be established for future reference. These include:

■

Developmental stages ■ Sex distinguishable ■ Tips of ears free ■ Papillae of facial vibrissae evident ■ Eyelashes visible ■ Eyes open ■ Fur visible – slight tinge, medium or well developed ■ Tips of first incisors through the gums ■ On back or in nest ■ Eating solids ■ Self feeding ■ Independent

■

Measurements (See Appendix 5) ■ Weight (g) – if not on teat ■ Head length (mm) – from the occiput to snout tip ■ Head width (mm) – maximum width across the zygomatic arches

■

■ ■

■

Crown rump length (mm) – primarily for very small neonates Body length (mm) – from snout tip to cloaca Tail length (mm) – from the cloaca to the end of the last vertebra of the tail tip Total length (mm) – from snout tip to tail tip Tibia length (mm) – from the hip to the bottom of the pes Pes length (mm) – from the heel to the base of the longest toe, not including the claw

10.3.2 Males The males of some species, including antechinus and phascogales, have a sternal gland that develops with age and reaches maximal development during the breeding season. The activity of the gland can be measured from the following scale (Woolley 1966; Millis 1995; Millis and Bradley 2001): 1. Little or no activity – little or no staining of the surrounding hair; little or no hair loss over the gland area; no obvious gland product.

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2. Medium level activity – some staining of the surrounding hair; some loss of hair over the gland area; waxy glandular products visible. 3. High activity – much staining of the surrounding hair; total loss over gland area; waxy glandular product prominent. In the males of most species, the size of testes can be measured as they increase during the breeding season due to the onset of spermatogenesis (P. Woolley pers. comm.). In antechinus, male testes are maximal up to six weeks before mating, at which point spermatogenesis stops (C. Dickman pers. comm.). Measure the length, width and depth of the testes in millimetres. Testis volume can be calculated by using the equation V=π/6 × (length) × (width)2 (Spencer 1996). The width of the scrotum has been used as a simple way of measuring increases in testis size successfully in captive studies (P. Woolley pers. comm.).

10.4 Techniques used to control breeding The timing of breeding can be determined by examining the urine for cornified epithelial cells, sperm and, in some species, a marked increase in body weight is observed (Godfrey 1969a; Woolley 1971a, 1971b; Close 1983; Gaikhorst 1999). The urine can easily be collected with a disposable plastic pipette or by pressing a clean slide against the cloaca immediately after capture (as subsequent urine will be much more dilute in sperm and epithelial cells) (Aslin 1980; Close 1983). Cells in the sample can then be examined immediately under 100× magnification (even without a cover slip)(Godfrey 1969a). Although some authors have used air-drying and staining with methylene blue (which stains the nuclei of the parabasal epithelial cells so they can be distinguished from anucleated epithelial cells) to determine oestrous (Close 1983), it is usually not required (P. Woolley pers. comm.). Once cells are detected, urine samples should be taken every one to two days and the number of cells per field of view can be scored as one of three scores: + cells present (Fig. 5a), ++ many cells present (Fig. 5b), and +++ cells are abundant (Fig. 5c) (Selwood 1982a). The males can also be examined to see if they are reproductively active by looking for sperm in their urine (Selwood 1982a). When the number of epithelial cells reaches ++ or +++ (which usually corresponds with a decline in body weight) the female should be mated with a male. Successful mating can be determined by direct observation or sperm present in the urine of the female (Fig. 5d)(Selwood 1982a; Taggart and Temple-Smith 1991). Close (1983) found oestrous in kowaris to be correlated with 20–50 anucleate epithelial cells and

leucocytes per 100× field, one to four days prior to the appearance of sperm in the urine or observed urine. Ovulation and mating have been induced in fat-tailed dunnarts by injecting gonadotrophins, but no fertilisation occurred (Smith and Godfrey 1970). This failure was attributed to an unexpected period between ovulation and mating when ova were retained in the oviduct. Despite the polygynous mating system of the dasyurids (Taggart et al. 2003), and most likely the thylacine and marsupial mole in the wild, they should only be put together as pairs during breeding and sometimes feeding, as they are generally solitary at other times. If held together throughout the year, they often will not mate as they appear to become too accustomed to their mate. In order to increase the potential of successful matings and encourage mating behaviour, males should ideally be rotated through the females every few days for species such as phascogales and antechinus that have very short breeding seasons of only several weeks. In species with longer breeding seasons, such as quolls and the Tasmanian devil, they should, if possible, be rotated every few weeks or, ideally, the technique described in Sections 9.3 and 9.8 should be used. Once the females have been observed to have successfully mated with one or more males or when pouch young are observed, the male should generally be removed (Aslin 1982). However, contrary to other research, kowaris have been held in family groups throughout the year, with young of several litters being raised together and in the presence of the male without trouble (Miessner and Ganslosser 1985). Deaths that were observed (21% mortality) were caused by negligence or mistreatment by the mother and not overt aggression by the male (Meissner and Ganslosser 1985). This compares with 39% mortality observed in a colony in which the mothers were isolated from other adults and kept in a relatively small cage (Aslin 1980). The fat-tailed dunnart is a strictly seasonal breeder with two peaks of birth, one in August and another in December, which coincide with a seasonal abundance of terrestrial invertebrates (Tyndale-Biscoe and Renfree 1987). The earliest births occur in the third week of July and the last in February (Godfrey and Crowcroft 1971; Morton 1978b). Therefore, the onset of breeding, both in the wild and in captivity, begins shortly after the winter solstice and ends some time after the summer solstice (Tyndale-Biscoe and Renfree 1987). Female fat-tailed dunnarts have been found to respond to increasing photoperiod from 12L:12D to 15L:9D by returning to breeding condition (Godfrey 1969b). The signal to begin breeding appears to be a response to a change from short


Figure 5. Changes in the number of cornified epithelial cells during oestrous from brush-tailed phascogales; a) At the onset of oestrous the number of cornified epithelial cells (CEC) is low and they are generally separate; b) As oestrus progresses, the number of CEC increases and cells begin to occur in groups; c) Large numbers of CEC that occur in clumps or sheets; d) Spermatozoa may often appear after mating within the clumps of epithelial cells. Taken from Millis (1995) with permission from Monash University.

87

88


to long day, as animals maintained in 16L:8D for most of the time and then exposed to 8L: 16D for three weeks ceased oestrous cycles during this period and resumed 20–30 days after the return to 16L: 8D (Smith et al. 1978). Bennett et al. (1982) used artificial lighting with success by maintaining fat-tailed dunnarts in 16L: 8D for 6 months, then a period of three weeks of 8L: 16D followed by a return to 16L: 8D. In these situations, the females are able to produce as many as five successive litters whereas in the wild females are not known to produce more than two litters nor produce in a second season (Morton 1978b; Smith et al. 1978). Brecken and Hulse (1972) bred fat-tailed dunnarts in 12D:12L conditions though this was only over one year and weaning success was very low. Long-tailed dunnarts have been bred successfully with artificial light in which the day length was adjusted every 10 days (Woolley and Valente 1986). The fat-tailed dunnart has been bred with great success by holding males with two to four females in artificial lighting, checking the females’ pouches one to two times per week and moving the female to a separate cage if she has pouch young (Bennett et al. 1990). As soon as the litter is weaned (about 65 days) the female is re-paired so that she can mate during the post weaning oestrous (Bennett et al. 1990). If pairs have not produced young within five weeks they are re-paired with another animal. The male is not reused if he has not sired more than one litter in three months of his initial pairing or within six weeks if he has previously mated successfully (Bennett et al. 1990). Importantly, these animals were held in artificial lighting in which it was found they had significantly more litters if ‘day length’ was varied by having long days (16L: 8 D) and short days (8L:16D) for approximately three weeks every six months (Bennett et al. 1990). Observations on agile antechinus under various day/ night lengths have also failed to result in animals breeding. Scott (1986) placed animals in short day length enclosures (10L:14D) to mimic breeding season but it had no effect on reproductive condition. If they were placed in short day enclosures, the reproductive condition appeared to be completely suppressed in both sexes (Scott 1986). In antechinus and phascogales the females are monoestrous with ovulation occurring synchronously each year. The timing in antechinus appears to be defined by an endogenous circannual clock with ovulation being determined by the absolute photoperiod and a precise threshold rate of change in photoperiod which acts as the major Zeitgeber (Dickman 1985; Selwood 1985; McAllan and Dickman 1986; Bradley 1987; McAllan et al. 1991; Halley 1992; McAllan

et al. 1999). Therefore, exposure to natural light cycles (ie sunlight) or the artificial light cycles that mimic it, which is unlikely to be achieved, is highly recommended to facilitate breeding of dasyurids in captivity. Brush-tailed phascogales are generally housed separately outside the breeding season, at which time several techniques can be used to mate animals. Firstly, a single male can be introduced into the female’s enclosure and kept there until pouch young are noticed in the female (Halley 1992; Slater 1993). Secondly, a round robin system can be used in which males are rotated through the females every few days while the females are in oestrous (with oestrous being determined by urine samples and generally occuring in the first two weeks of May in Victoria) (Halley 1992; Millis et al. 1999). An analysis of a colony of fat-tailed dunnart breeding records showed that a female that does not produce a litter after being paired with a male for two or more oestrous cycles is more likely to reproduce if paired with a different male than if she stays with the first male (Smith et al. 1978). It appears that many of the species of dasyurids, particularly the quolls and Tasmanian devil, do not mate well with individuals that they have regularly housed with, even during the receptive period (Settle 1978; Gaikhorst 1999; pers. obs.). Female quolls also do not appear to tolerate being re-mated by the same male, and can become extremely aggressive, unless they have since been mated by a second male (Settle 1978). This may reflect that in the wild they would meet and socialize with a number of different males prior to the breeding season but den alone (M. Jones pers. comm.). A number of feeding regimes have been used to increase the likelihood of breeding. These include a reduction diet where approximately one week after reducing the diet the female is expected to go off her food. When off her feeding (usually in oestrous) the male is introduced and the female should submit to mating. They are usually kept together three to five days but can go to 10 days before the female dominates the male (A. Gifford pers. comm.). The alternative is to feed the female half her body weight in food every second day and repeat until she refuses to eat, at which time the male is introduced (A. Gifford pers. comm.).

10.5 Occurrence of hybrids None known at this stage.

10.6 Timing of breeding Oestrous is highly synchronized in most species of dasyurids and can occur at any time of the year,


depending on the species (Table 10). Behavioural oestrous in agile antechinus lasts up to 11 days, seven days in yellow-footed and dusky antechinus, two to three days in the dunnarts, one to three days in the kowari, three days in quolls, five days in phascogales and one to three days in ningauis and planigales, so several bouts of copulations can occur (Marlow 1961; Woolley 1966; Tyndale-Biscoe and Renfree 1987; Taggart et al. 2003). Almost all dasyurids are seasonal breeders, with the period of late spring and early summer generally coinciding with late lactation and pouch emergence in temperate Australia and with the post monsoonal period in northern Australia (Tyndale-Biscoe and Renfree 1987). The timing of breeding seasons for various carnivorous marsupials is shown in Table 10.

10.7 Age at first and last breeding Although male antechinus and phascogales die or are reproductively sterile after mating, the females can survive to reproduce to a second, or rarely a third, year (Lee et al. 1982; Lee and Cockburn 1985) (Table 11). Most dasyurids reach reproductive senescence before they die in captivity so careful management is required of the captive population. If space is limiting and breeding is not stopped, it will result in an aging population and ultimately the demise of the colony. Therefore, if space is limiting, it is recommended to euthanase reproductively finished stock rather than stop breeding. Breeding should be allowed to begin as soon as the individuals are sexually mature and not stopped, as this invariably results in no breeding when attempts are made to start it up again. The health and longevity of the colony should be placed ahead of the individual, particularly as these surplus individuals would be dead in the wild anyway and survive in captivity only because of the optimal conditions and food availability.

10.8 Ability to breed every year All species are able to breed every year, however the species with Strategy 1 reproduction, such as the antechinus and phascogales, only have one breeding season (Lee et al. 1977; Lee and Cockburn 1985). In captivity, the males of both species can live longer than a year, however they are normally sterile (Woolley 1966; Dickman 1993; Slater 1993). This can be seen in brush-tailed phascogales by the scrotum that appears blue as a result of hair loss from the scrotal skin and the black pigment in the tunica vaginalis, which is visible through the skin (pers. obs.; P. Woolley pers. comm.). Apart from these species, all the others should be

encouraged to breed every year, as they will generally not breed again if stopped for one or more years. Many dasyurids often do not breed at all if they do not breed in their first year (Carnio 1993), so all attempts should be made to breed them in their first year in order to maximize their reproductive output.

10.9 Ability to breed more than once per year Most species of dasyurid are polyoestrous, except antechinus and phascogales, in that they are able to undergo oestrous if the first young are lost (Tyndale-Biscoe and Renfree 1987). The only true monoestrous dasyurids are the antechinus and phascogales where the males die after mating (Kitchener 1981; Cuttle 1982b; Lee et al. 1982; Slater 1993). Fat-tailed dunnarts can breed twice per year as the female can go into oestrous one or two days after the young finish weaning and the second litter can be born 82–90 days after the first litter was born (Bennett et al. 1982). Similarly, kowaris and planigales can produce two litters per year (Woolley 1971b; Woolley 1973; Fletcher 1983; Strahan 1995). The lesser hairy-footed dunnart breeds irregularly in the wild, but could potentially breed more often in captivity due to the greater availability of food and water (Dickman et al. 2001). Stripe-faced dunnarts, for example, are known to produce three litters per year in captivity (P. Woolley pers. comm.). In contrast, wild observations on mulgara and wongai ningaui showed them not to breed more than once per year (Dickman et al. 2001).

10.10 Nesting requirements Nest boxes and/or hollow logs should be provided for all species of dasyurids, the thylacine required a sheltered area and the marsupial moles do not need anything. Thylacines used lairs in caves and probably large hollow logs or stumps so they probably did need quite a lot of privacy when held in captivity (although they were not provided with it) (M. Jones pers. comm.). Although Troughton (1973) suggests that female marsupial moles make a deep burrow in which they produce their young, he also suggests that nothing definite is known about their breeding biology.

10.11 Breeding diet Additional food should be provided to the males prior to breeding (especially for quolls) as they have been known to kill and partially eat their proposed mates, and for lactating females, as a shortage will often result in cannibalism of the young (see Section 9.8).

89

90

Table 10. Reproduction and development of the carnivorous marsupials. d = days, m = months Mating Period

10–11

10–11

Aug–Sep

Sep–Oct

1, 2, 3, 4, 5, 6

8–9

8–9 or

May–Oct

Jun–Dec

4, 7, 8, 9, 10, 11

Sexual Maturity F (m)

88

100–120

70–78

100–120

Birth Season

First detach (d)

D. cristicauda

2–6 (5)

55–60

D. byrnei

4–6 (5)

55

D. rosamondae

6–8

–

–

100–120

10

10

Sep

Nov

D. geoffroyi

1–6

–

61

110–54

12

12

Apr–Jul

May–Sep

Reference

Dasyuridae

12 13, 14, 15

D. hallucatus

6–8 (7)

60–70

56–70

125–50

10–11

May–Aug

Jul–Sep

–

D. maculatus

4–6 (5)

35–49

96

125–150

12

12

Apr–Jul

Jun–Aug

21, 22, 23, 24

D. viverrinus

1–6 (6)

49–65

91

135–140

12

12

May–Jun

May–Aug

17, 25, 26, 27, 28, 29

8

–

–

90–120

10–11

10–11

Mar–Apr

Apr–May

18, 30, 31

4–6

–

c. 30–45

c. 90

12

12

May–Jul

Aug–Sep

14, 32

–

–

–

112

10–11

10–11

Jun

Jul–Aug

33

P. macdonnellensis

5–6

–

–

98

12

12

Jun–Jul

Jul–Oct

34, 35

P. woolleyae

4–6

–

–

–

10

10

–

–

1–4 (3)

90–105

105

150–280

24

–

Mar–Apr

Apr–May

P. apicalis P. bilarni P. ningbing

S. harrisii

16, 17, 18, 19, 20

14 27, 36, 37

A. agilis

6–10

35

35

c. 90

10–11

10–11

Aug

Sep

14

A. bellus

1–10

28–35

–

c. 100

10–11

10–11

Aug

Sep–Oct

38

A. flavipes

1–12 (7)

42

36

90–120

10–11

10–11

Jun–Sep

Jul–Oct

18, 39, 40

A. godmani

1–6

–

–

–

10–11

10–11

Jun–Aug

Jul–Sep

41

8–10 (9)

–

–

–

10–11

10–11

Sep–Oct

Oct-Nov

42

–

–

–

–

10–11

10–11

May–Jul

Jun–Aug

43, 44

6–8

35–45

35

90–110

9–10

–

Jul–Aug

Aug–Sep

45*, 46*, 47, 48, 49

A. leo A. minimus A. stuartii A. swainsonii

4–8

33–43

56

90–95

10–11

10–11

–

Aug

6–8 (7)

–

–

90+

12

11.5

Jul

Jul–Aug

P. tapoatafa

3–8 (6)

49–54

49–54

120–140

7.5

11

May–Jul

Jun–Aug

56, 57, 58

P. gilesi

6–12 (7)

37

37

65–70

–

–

Jul–Dec

Aug–Jan

59, 60

P. ingrami

4–10 (7)

35–40

35–40

90

–

–

Nov–Feb

Dec–Mar

61, 62, 63, 64, 65

P. maculata

4–12 (8)

28

45

70

10

–

Jan–Dec

Jan–Dec

66, 67

P. tenuirostris

4–12 (6)

40

40

c. 95

–

–

Jul–Jan

Aug–Feb

59

5–7

42–44

48–49

70–81

10

6–11

Sep–Dec

Oct–Jan

6, 68, 69

4–6 (5)

–

–

–

–

0.7 kangaroo milk replacer then increased by 50% strength after one week. Make up a half batch and freeze into small portions that can be defrosted each day. ■

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118


Table 3. Concentrations of major constituents of numbat milk. Total Solids (%)

Carbohydrates (%)

Lipids (%)

Protein (%)

Calcium (mg/L)

Iron (mg/L)

28.0

2.0

12.0

14.0

–

–

Data from Griffiths et al. (1988)

■

■

■

■

■

■

Feed every three hours (1–2 ml initially) per feed. At this stage animals will require to be fed at night at least once. The quantities per feed will increase daily to meet their needs. Stimulate bowel movements by gently wiping the cloacal area with a dampened cotton wool ball. Fully furred young don’t require stimulation, however, it is essential to check that this function is working properly. A small shot glass on a folded paper towel inside a small stainless steel bowl is a good feeding utensil, as it allows only the long tongue and snout access to milk. Introduce the artificial diet into milk formula (5 g) once a day when lapping is established. Within 21 days, young will consume close to 10 ml each. Start to increase the artificial diet by 5 g every three days. Artificial diet can be placed into a regular feeding bowl when young are eating freely.

When supplementary feeding has been warranted, only one or two days are required until young accept the artificial diet.

11.5 Data recording When an animal is first brought in for hand-rearing, its sex and approximate age, or developmental stage, should be recorded. During the hand-rearing process, a number of important pieces of information should be recorded. This information serves several purposes, including providing important background information such as appropriate food consumption which will assist a veterinarian reach a diagnosis if the animal gains weight, becomes sick or fails to grow. The following information should be recorded on a daily basis: ■ ■ ■ ■

11.4 Specific requirements No unfurred pouch young have ever been successfully hand-reared. Only pouch young at least six months of age, which are fully furred and eyes open have been successfully reared to independence. When first brought in for hand-rearing the animal may be dehydrated. Vytrate, a well-known electrolyte replacer for oral rehydration, can also be used at a ratio of 20 ml Vytrate to 250 ml water. It is important to warm the joey prior to feeding to minimize the risk of inhalation pneumonia. If this takes too long, give fluids subcutaneously and bottle-feed later. If the joey is very cold, place it in a warm water bath and dry it off rather than putting it in a hot box (J. Cowie pers. comm.). Stress is a major problem in the rearing of native mammals. Therefore it is important that noise is kept to a minimum, the numbat joeys are not overhandled and high standards of hygiene are maintained. Some supplementary feeding of normally lactating young has been undertaken to fast track the weaning process if the mother is showing signs of stress. This may be indicated by weight loss of the mother or the young.

■

■ ■ ■

Date Time when the information is recorded Body weight to the nearest 1 g if possible General activity and demeanour Characteristics and frequency of defecation and urination Amount (g) of different food types offered Food consumption at each feed Veterinary examinations and results

The developmental stages and measurements outlined in Section 10.3.1 should also be recorded on a weekly basis if possible.

11.6 Identification methods The band markings across the back of each animal are a unique fingerprint for that individual. From six months of age they can be clearly identifiable. Vegetable dye can be painted on individual feet as another method of distinguishing individuals.

11.7 Hygiene As with any mammal, maintaining a high standard of hygiene is critical to the survival of the individual. Feeding utensils should be cleaned and sterilised after each use. Formula should be freshly prepared each day and stored appropriately.

Numbats

11.8 Behavioural considerations The young will need to learn various behaviours from its mother, which include nest building, socialisation and flight/fright responses. It may be advisable to place the young numbat(s) with a non-lactating female or a surrogate female that has recently weaned her young. Young should have access to natural sunlight or access to a basking lamp.

11.9 Use of foster mothers Numbats have been fostered successfully onto other lactating numbats whose own litters have been recently weaned.

11.10 Weaning Once lapping, they can be weaned by providing termites in their custard and free live termites in a bowl, as well as termite mound in their enclosure. At weaning, fresh water should be supplied.

11.11 Rehabilitation and release procedures There is a recovery plan for the numbat in Western Australia, managed by the WA Department of Conservation and Land Management. Translocation of numbats to areas of its former range where introduced predators are controlled is one of the actions of the plan. The young animals thus require preparation prior to their release. Preparations include the following: ■

■

The young numbats have their diet changed to 100% termite diet a few weeks prior to release. Diet and body weight are monitored closely; body weight should not exceed 350 g, as there may be difficulty in fitting the radio collars. If animals are too fat when collared the collars may slip off as a result of post-release weight loss. Termite infested logs are provided.

■

■

Termite mound is provided daily for enrichment and to stimulate activity. All young undergo a pre-release physical (see Section 8).

Unfortunately, many captive numbats have suffered from predation following their release into the wild (N. Thomas, pers. comm.). Numbats have many predators, including foxes, cats, carpet pythons and birds of prey. It appears that birds of prey are one of the main causes of fatalities in young juvenile numbats, particularly when they are at weaning age and beginning to venture from the safety of their underground burrows (N. Thomas, pers. comm.). In 1998 a small trial was conducted to determine if young captive-born numbats had an instinctive fear response and if there was a learned response from the presence of the mother (V. Power pers. obs.). A predator awareness training program has been initiated and is still ongoing. Results from radio tracking during the last two years indicate that there is a survival bias towards individuals that have undergone behavioural/predator awareness training.

12. Acknowledgments Thanks to Dr Terry Fletcher for assisting in editing and providing valuable input into the manuscript. Thanks go to Dr Peter Spencer for assistance in editing this manuscript. Many thanks to Dr Tony Friend for all his help with valuable advice over the years of the numbat program. A sincere thank you to all the staff on NSBP who have contributed to the numbat breeding program over the years. Thanks to Dr Stephen Jackson for providing many of the references, significantly editing the manuscript and putting together the growth curve. From 1995–2003 the numbat breeding program was supported by the Australian Government’s Cooperative Research Centres Program and McDonald’s Family Restaurants.

119

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Addendum 1. Sustainable termite harvesting techniques Introduction Invertebrate propagation plays an important role in the maintenance of many species held in captivity. This is particularly important for the numbat, which is an obligate termite feeder. A reliable termite supply is therefore essential. A method of collecting termites was developed by Dr Geoff Kirkman and Dr Tony Friend to supply termites for the numbat program. The basic principle is to lure termites into an open-topped drum packed with Karri wood (one of their preferred foods). Once the wood has been infested with termites, the drum is brought back from the bush to a place where the termites can be separated from the wood. Nests are not destroyed, and when yields start to diminish, the termite drums (traps) are removed, allowing the nests to recover. Perth Zoo has established collection sites that are mainly within water catchment areas with limited public access or on private land. It is essential to have many sites established in the event of a natural disaster (bush fire) or destruction of the drums by vandals.

Termite harvesting Nasutitermes exitiosus is Australia’s best-known species of termite. It occurs across southern mainland Australia, from the southern half of Western Australia east to the Pacific coast, but is absent from Tasmania (Watson and Abbey 1985). Coptotermes acinaciformis is a common and widely distributed termite species in Western Australia and is certainly the most abundant and destructive species in the southern part of the state (Calaby and Gay 1956). Both these species are found in the Perth metropolitan area, but neither is trapped in this area due to the probable use of pesticides and the risk of transfer of residual chemicals to the numbats. In summer we concentrate trapping efforts on Coptotermes as larger quantities are consistently trapped. During the winter months trapping Nasutitermes can often be more productive than trapping Coptotermes if you locate a large enough nest.

How to find termites 1) Nasutitermes exitiosus The mounds of N. exitiosus (Fig. 9) found near the coast in sandy low rainfall areas are low, 200–400 mm and thin-skinned, but smooth and domed shaped with most

Figure 9. Nasutitermes spp. mound in woodland east of Perth. Photo by V. Power.

of the nest underground (Eutick 1983). On the Swan coastal plain, mounds have been noted as high as 1 m making them very easy to find and each could house over a million insects. The head of a soldier of Nasutitermes spp. is shown in Fig. 10. 2) Coptotermes acinaciformis Coptotermes have underground nests, often at the base of trees. These are usually detected by locating their feeding galleries, which radiate out from the nest (Hadlington 1987). The galleries can be found by turning fallen dead-wood over and looking for termite activity, or by placing pieces of Karri wood (baits) on the ground and returning a few weeks later to check for activity. It does not matter what size this bait-wood is (80 mm × 40 mm × 300 mm lengths are good), but it is important to wriggle them into the ground well so they make good contact with the dirt. Fallen bark at the base of trees, and under small clay mounds or bumps at the sides of trees are also good places to look for termites. The head of a soldier of Coptotermes spp. is shown in Figure 11.

Numbats

Figure 10. Dorsal view of the head of a soldier of Nasutitermes spp.

Figure 11. Dorsal view of the head of a soldier of Coptotermes acinaciformis.

Preparing the termite traps

bag combine to create a humid environment, which is attractive to termites. In some cases, when water is splashed into a drum it washes the soil away from around the base, so it may be best to water the drum before you set it in place.

Open-topped drums (15–20 litres) are used by drilling 8 × 12 mm holes in the bases. Obtain some Karri wood, free of debris and fungus and (importantly) pesticide and fungal-treatment free, preferably about 10 mm thick, but no more than 20 mm. These slats can be about 50–120 mm wide, and should be cut to lengths of about 450 mm. Pack the drums with the Karri slats. A neat well-packed drum will create a more attractive environment for termites. The wood must be tight enough so that it does not slop around in the drum.

Setting the termite traps Ants are a threat to termite nests, and great care must be taken when setting drums, to avoid leaving the nests or galleries exposed to infiltration. The soldier termites can repel a few ants, but whole nests can be destroyed if ant numbers are great. It is therefore important that you have everything you need to set up a drum on hand before you expose any termites. Trapping methods for Nasutitermes species Use a spade to cut the top off the mound. Make a flat surface for the drum to sit on, which is slightly larger than the drum. This will allow room to push dirt around the base of the drum, avoiding gaps for ants to get into the mound or under the drum and into the wood. Once all gaps around the base of the drum have been sealed, splash about 500 ml to 1 litre of water over the wood. Put a heavy-duty garbage bag over the drum and pull it down to about halfway. Exclude air from the bag, twist the excess plastic around the drum and tuck it under, giving the bag a nice tight fit (Fig. 12). The moisture and plastic

Trapping methods for Coptotermes species Once galleries have been located (you can see the honeycomb looking holes), drums are simply placed on top of them (Fig. 13). Dirt or mud is built up around the drum to seal it, and water and a plastic bag are applied as for the Nasutitermes sp. mounds. During the summer months large numbers of Coptotermes are found in the Metal drum is packed with moistened karri wood slats and covered with a black plastic bag Holes perforated into base of drum to allow termites access to bait wood

Thin fragile outer casing

Nest chamber is of a thin papery texture

Figure 12. Trapping techniques for Nasutitermes sp.

121

122


Coptotermes sp. nesting within hard wood tree. Nest area is of a hard, woody honeycomb-like carton material. Calaby and (Calaby and Gay Gay 1956)

Termite galleries leading in and out of nest chamber.

Termite trap packed with moistened bait karri slats and sealed with black plastic bag.

Figure 13. Trapping techniques for Coptotermes sp. Depending on how large the nest is, up to six termite traps can be set around a termite-infested tree.

traps, so we predominantly trap this species. Many termite traps can be set around a termite-infested tree.

Replacing the drums when full Termites are very active in summer, and a good site may yield a full drum within two to three weeks. In winter, a drum on the same nest may take a couple of months to fill. When replacing drums, remove the plastic bag covering the full drum and open it out on the ground. Beneath the garbage bag, a very full drum may be completely encased in mud by Coptotermes. Carefully lift the drum and sit it in the bag, pulling the sides up and tying the bag tightly so that the drum is enclosed. Use a new bag if the old one has small holes or tears in it. A good drum can be stuck quite solidly to the ground and may need a bit of force to remove it. Put a replacement drum immediately back onto the nest or gallery, and ensure that the base is quickly sealed with dirt or mud to exclude ants. Apply water and a plastic bag as described earlier.

Storing full drums If necessary, drums of termites may be stored for up to a week before separating the termites from the wood. However, they must be kept out of the sun and wind, and stored on ant-proof tables. To prevent drums from drying out, the drums should be stood on top of damp Karri slats inside a plastic tray. Tables must be freestanding, and can be made ant-proof by spreading a thick grease barrier (about 60 mm long) around each leg. It is important that nothing is leant against the tables either, as the ant-barrier will be broken. Even a broom or leaves caught in a cobweb may create a bridge that will allow ants onto the table. A bridge like this can permit enough ants onto the table to infiltrate and ruin the

termite drums within a few hours. Obviously, pesticides should never be used for ant control as the termites may die too!

Separating the termites Termites are very delicate, and will crush easily if roughly handled. They also dehydrate quickly, so the plastic bag surrounding the drum should always remain intact. Dust masks should be worn during termite separation, and gloves (rubber or thin cloth) can be worn to protect against bites from the soldier termites, but are usually not necessary. Using a ‘bashing tool’, take one Karri slat at a time from a drum and hit the end of it in a downward motion, so the termites fall into a large plastic tray. Keep doing this until you have ‘bashed’ all the slats. There will now be termites plus a lot of dirt in the plastic tray. Separate the termites from the mound material by tipping the whole lot onto a ‘platform’ (Fig. 14), which is sitting in a large plastic tray (Gay et al. 1955). The termites don’t particularly like the light and will quickly fall off the edge of the ‘platform’ into the plastic tray beneath. The pure termites can then be tipped into an icecream container (or similar). Icecream containers are good because the sides are slippery, and the termites cannot climb out. If the termites are very slow and don’t look like they are going to move, then you can take a very thin, light slat, spray it lightly with water and place it gently on top of the termites and dirt. The termites should congregate on the underside of the slat, and can be tapped off directly into a tray and then into an icecream container. Do not put more than about 25 mm of termites into a container, or the bottom ones may crush. Once you have bashed out all the termites from a drum, there will still usually be a large number remaining in the dirt in the

Numbats

620 mm

table inside tray (top view) Table inside tray (top view)

380 mm

for a day before freezing in icecream containers in the fridge. Plastic zip-lock bags are good, and all air should be expelled from the bag before sealing. Label the bags with the date and weight (100 g portions are ideal). It is important to have pure termites only – careful separating will ensure that all debris is removed.

Equipment for trapping termites ■

Leg supports

■ ■

Bevelled edge

Figure 14. Design of perspex termite separation platforms. Taken from Friend and Whitford (1988) and Gay et al. (1955).

bottom of the drum. To collect these, take three or four wide slats, spray them with water, and place them – so there are no gaps between them – back in the drum and close the plastic bag around it. The termites will move out of the dirt and up onto the slats, and can be smacked off a short time later. This ‘milking’ of the remaining termites in the drum may continue a number of times over a couple of days until most termites have been collected. At the end of a harvesting session, tip any dirt/ termite mix back into the drum it came from, and they can then be separated out along with the other termites that were left in the bottom of the drum. Never leave termites on dividers or in trays overnight or even for a few hours in hot weather, as they will dehydrate and die very quickly. In hot weather it is advisable to place damp paper towels over the top of the (delicate) termites on the trays while you work on other drums. Do not mix termites from different drums (even if they are the same species), as the soldiers from different nests may fight. All equipment, particularly the trays, dividers and icecream containers, must be kept clean. Accumulated excreta gives the termites something to climb up, allowing them to escape.

Freezing the termites Termites can be frozen for future use without losing their nutritional value or palatability to numbats (our unpublished analysis). The sooner they are frozen after separating the better, but if necessary, they can be stored

■ ■

Open-topped drums. We use 15–20 L drums, which are between 300 and 400 mm high Karri slats Heavy-duty garbage bags Water container Spade

Equipment for separating termites (see Fig. 14) ■ ■

■

■

■ ■ ■

■ ■

Ant-proof table for storing termite filled drums Large plastic trays (700 mm × 450 mm × 90 mm high) Metal ‘dividers’ – thin piece of sheet metal (600 mm × 350 mm), with bolts put through on each corner and one in the middle, to act as legs. The divider should stand about 35 mm high. Rubber or thin cotton gloves – you can also use padded gloves, to provide some shock absorption for when you’re bashing Dust masks Water spray bottle ‘Bashing’ tool – use whatever size and weight fits best into the person’s hand, but it does require a little weight behind it. We use a solid metal rod, 13 mm diameter, 350 mm long. One end can be flattened (like a screwdriver) and slightly bent, to aid in levering slats out of the drums. The other end should be covered in a shock-absorbent rubber or foam. Icecream containers Zip-lock plastic bags.

Occupational Health and Safety Concerns This work could result in repetitive strain injuries to a person who performs it all the time. It is advisable to rotate staff regularly to minimize this risk. Wearing a support glove on the hand that takes the impact from the metal bashing tool is also recommended.

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Addendum 2: Artificial diet preparation of egg custard No. Animals

Water (ml)

Eggs (gm)

Digestelact (gm)

CaCO3 (gm)

SF40 (gm)

Termite mound (gm)

1

57

30

12.3

0.38

0.08

5

3

171

90

36.9

1.13

0.23

15

4

228

120

49.2

1.5

0.3

20

8

450

240

104

3.75

0.75

50

10

570

300

123

3.75

0.75

50

11-12

680

360

151

3.75

0.75

50

13-14

800

420

180

3.75

0.75

75

15-16

910

480

198

5.63

1.5

100

17-18

1020

540

227

5.63

1.5

100

20

1140

600

246

7.5

1.5

125

Teaspoon Ca Co = 7.5 g Teaspoon SF40 = 3.0 g

Numbats

Addendum 3. Example of 100% termite diet prior to breeding season (November–March) in numbats Sex

Time Fed

Female

a.m. (8.30 am)

40 termites

p.m. (1.30 pm)

30 termites

Male

Amount (g)

a.m. (8.30 am)

30 g AD + 5 g termites

p.m. (1.30 pm)

30 g AD + 5 g termites

Termite crumb feed during the day to all. Note: AD denotes an artificial diet.

If termite supplies are good, endeavour to provide a 100% termite diet whenever possible; considerable success has also been achieved with a 60% termite diet.

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5 BANDICOOTS

Stephen Jackson

1. Introduction The bandicoots, whose name means pig rats (Collins 1973), are an interesting group of mammals that are rodent-like in appearance. Although their common name is derived from a genus of rodents (Bandicota) that occurs in Asia, they are in fact marsupials with a well-developed pouch. There are a total of 21 recognized species that occur throughout Australia, New Guinea and surrounding islands. Despite the appeal of some species, especially the very popular greater bilby, the bandicoots have been poorly represented in zoos, and most animals in captivity have generally been held in research institutions. Western-barred bandicoots were held and bred as early as 1924 (Jones 1924), long-nosed bandicoots have been held in the McMaster Laboratory in Sydney since 1954 (Collins 1973), southern brown bandicoots and eastern-barred bandicoots have been held by the University of California (Heinsohn 1966). The University of Tasmania has kept both southern brown bandicoots and eastern-barred bandicoots at various times, and researchers have also kept long-nosed bandicoots and northern brown bandicoots (Seebeck pers. comm.). Rufous spiny bandicoots have rarely been held in captivity although there are records of them being kept at the National Zoo in Washington in 1972 (Collins 1973). Bilbies have been displayed since as early as 1848 when they were displayed at London Zoo and subsequently at unrecorded times in the late 1800s to early 1900s at Frankfurt Zoo and Philadelphia Zoo in 1904 (Collins 1973). More recently, bilbies have been held at Monarto Zoo, Taronga Zoo, Western Plains Zoo in Dubbo, Adelaide Zoo, Currumbin Sanctuary and the Alice Springs Desert Park in the Northern Territory. Other species, such as golden bandicoots, have been held at Perth Zoo and Territory Wildlife Park and eastern-barred bandicoots are found in Adelaide Zoo, Western Plains Zoo in Dubbo, Healesville Sanctuary, Melbourne Zoo and Taronga Zoo as part of a recovery plan for introduction of this endangered species (Lees and Johnson 2002).

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2. Taxonomy 2.1. Nomenclature The bandicoots contain two separate families within the Order Peramelemorphia and consist of 21 species. Of these, nine are found only in Australia, 10 are found only in New Guinea and surrounding islands and two species are found in both regions (Seebeck et al. 1990; Flannery 1995a, 1995b; Strahan 1995; Table 1). Australian Bandicoots Class: Mammalia Supercohort: Marsupialia Cohort: Australidelphia Order: Peramelemorphia Family: Peramelidae Subfamily: Peramelinae Genus Species: three genera, eight species Subfamily: Thylacomyinae Genus Species: one genus, two species Family: Peroryctidae Genus Species: one genus, one species Etymology See Strahan (1981).

2.2 Subspecies See Strahan (1995).

2.3 Recent synonyms Synonyms for Australian bandicoots can be found in Mahoney and Ride (1988a, 1988b) and Strahan (1995).

End and Kimberley tropics of Australia, desert bandicoots were strictly desert inhabitants, bilbies are also desert dwellers, although they once occurred in both arid and semi arid regions of central Australia, while the eastern-barred bandicoot prefers grasslands and brown bandicoots live in more closed forest (Strahan 1995; K. Johnson pers. comm.). Members of the family Peroryctidae all occupy more tropical environments. More specific details of the distribution and habitats occupied by the Australian bandicoots can be found in Seebeck et al. (1990) and Strahan (1995).

3.3 Conservation status Overall the bandicoots have not done well since European settlement in Australia, with three species having gone extinct, one species becoming endangered and one species is considered vulnerable or rare out of only 11 species, which has primarily been as a result of the introduction of foxes onto the mainland of Australia (Table 1).

3.4 Diet in the wild Bandicoots are typically omnivorous though specific diets are known for few species. They typically eat a wide range of invertebrates, bulbs and grasses, with fungi also contributing to the diet of at least some species (Claridge and May 1994; Strahan 1995). Further details of the diet of different genera can be found in Table 2 and Strahan (1995).

3.5 Longevity 3.5.1 Wild

Australian bandicoots range in size from approximately 150g to 2500g (Table 1) (Flannery 1995a, 1995b; Strahan 1995). The morphometrics of Australian species can be found in Strahan (1995).

Bandicoots are typical of species that breed rapidly in that they die at a relatively young age. The mean longevity for Perameles is only one to two years, with eastern-barred bandicoots living for an estimated 7.9 months for males and 10.5 months for females in the wild (Mallick et al. 2000). Isoodon species may live up to four years of age. Although little is known of the longevity of the bilby in the wild, they live for at least one year and most probably live for at least as long as Isoodon (Table 3). Nothing is known of the longevity of the Peroryctidae.

3.2 Distribution and habitat

3.5.2 Captivity

Bandicoots occur throughout mainland Australia and New Guinea and surrounding islands in a wide range of habitat types. Pig-footed bandicoots once occurred in the southern grasslands, golden bandicoots occur in the Top

Like other species, bandicoots live longer in captivity with most species typically living at least two to four years. Though there are records of bilbies living up to 10 years in captivity they typically live five years (Table 3).

2.4 Other common names See Strahan (1995).

3. Natural history 3.1 Morphometrics

Bandicoots

Table 1. Species of bandicoots within Australia and their conservation status. Common Name Family Peramelidae Subfamily Peramelinae Pig-footed bandicoot Golden bandicoot Northern brown bandicoot* Southern brown bandicoot Western-barred bandicoot Desert bandicoot Eastern-barred bandicoot Long-nosed bandicoot

Scientific Name

Weight (g)

IUCN Status

Chaeropus ecaudatus Isoodon auratus Isoodon macrourus Isoodon obesulus Perameles bougainville Perameles eremiana Perameles gunnii Perameles nasuta

200 250–670 500–3100 400–1600 170–290 ? 450–1450 500–1900

EX VU LR (lc) LR (nt) EN EX VU LR (lc)

Subfamily Thylacomyinae Bilby Lesser bilby

Macrotis lagotis Macrotis leucura

800–2500 310–435

VU EX

Family Peroryctidae Rufous spiny bandicoot*

Echymipera rufescens

500–2000

LR (lc)

*also occurs in New Guinea and/or surrounding islands; VU – vulnerable, EN – endangered, EX – extinct, LR – lower risk, nt – near threatened, lc – least concern From Seebeck et al. (1990), Flannery (1995a, 1995b), Strahan (1995), Maxwell et al. (1996)

3.5.3 Techniques to determine the age of adults There appears to be no useful technique for determining the age of adult bandicoots. An examination of various parameters in long-nosed bandicoots included various skull measurements, time of eruption of teeth, wear of the teeth, rate of deposition of dentine and cementum in the teeth, size of the lenses and time of epiphyseal fusion (Kingsmill 1962). None of these measures were found to provide satisfactory results (Kingsmill 1962). The only age classes that could be distinguished were zero to four months and greater than four months, using the degree of fusion of the epiphyses of the limb bones (Kingsmill 1962).

4. Housing requirements

branches should also be added. Some species, such as members of the genus Isoodon and Perameles, generally prefer habitat with good vegetation cover; efforts should be made to provide cover, but it should not be so thick that they cannot be seen.

4.2 Holding area design Holding enclosures should have sheet metal lining to a minimum of 1.5 m because some bandicoots, such as the eastern-barred bandicoot, can jump 1.2 m and climb mesh. The substrate should be approximately 10–20 cm deep (Kingston 1998). At least one end of the enclosure should be covered to allow them to shelter from rain (Kingston 1998). The mesh should be bird netting or fabric mesh with a hole of 1.2 cm (Williams 1990).

4.1 Exhibit design

4.3 Spatial requirements

Due to their nocturnal behaviour, bandicoots are often displayed in nocturnal houses. Most species are readily held in enclosures with a deep layer of soil, leaf litter and/ or mulch, which is at least 10 cm deep so that they can dig a nest depression in it. Various tussocks, hollow logs and

Bandicoots can be held in relatively small enclosures, which may be useful for the intensive breeding required for breeding programs, such as that of the eastern-barred bandicoot (Table 4). If possible, enclosures should be made larger to further reduce the chance of aggression

Table 2. Diet of different genera of bandicoots. Genus Chaeropus Isoodon Perameles Macrotis Echymipera

Food Types Grasses Various invertebrates – worms, snails, ants, larvae, insects, frogs, fungi, grasses, seeds, mosses Various invertebrates – worms, snails, insects, slugs, frogs, fungi Insect larvae, other insects, termites, ants, bulbs, seeds, plant fibre, rodents? Invertebrates, fruits, plant matter

Refs 1, 2 3, 4, 5, 6 3, 5, 7 2, 8, 9 10, 11

References: 1 Wright et al. 1982; 2 Dixon 1988; 3 Heinsohn 1966; 4 Quin 1985; 5 Claridge and May 1994; 6 Reimer and Hindell 1996; 7 Claridge 1993; 8 Southgate 1990; 9 Gibson 2001; 10 Flannery 1995a; 11 Strahan 1995.

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Table 3. Longevity (months) of different genera of bandicoots in the wild and in captivity. Number in brackets is the average longevity. Captivity

Table 4. Minimum areas of enclosures recommended for pairs of different genera of Australian bandicoots. Genus

Area (L × B × H) (m)

Additional Floor Area for Each Extra Animal (m)

1, 2

Isoodon

4×4×2

2.5 × 2.5

3, 4, 5

Perameles

4×4×2

2.5 × 2.5

Macrotis

5×5×2

3.0 × 3.0

Echymipera

4×4×2

2.5 × 2.5

Genus

Wild

References

Isoodon

42–48

23+

Perameles

7.5–24+

36+

Macrotis

12+

48–120 (60)

6, 7

References: 1 Gemmell 1990; 2 Lobert and Lee 1990; 3 Heinsohn 1966; 4 Dufty 1991; 5 Mallick et al. 2000; 6 Flower 1931; 7 Southgate et al. 2000.

and stress in females with young. Single and paired animals have been kept in very small enclosures, 76 × 60 × 40 cm, with stainless steel sides and floor. In these enclosures, northern brown bandicoots bred (though not as well as in larger, outdoor enclosures) but long-nosed bandicoots rarely bred in these cages compared with frequent breeding in outside enclosures (Lyne 1982). Bilbies should not be held on metal flooring as they have been found to develop foot abscesses (K. Johnson pers. comm.).

4.4 Position of enclosures The enclosure should be away from significant traffic and other noises and positioned so that it is protected from wind and rain. Exposure of enclosures to heat is a factor in northern and desert regions of Australia (K. Johnson pers. comm.).

4.5 Weather protection Protection from extremes in weather, especially exposure to very hot weather or heavy rain and strong wind, is necessary. It is recommended that at least one-third of the enclosure (particularly the end facing the direction of inclement weather) should be covered. Shade cloth can also be used to increase the level of shade in very exposed enclosures (Kingston 1998).

4.6 Temperature requirements Heating is generally not needed for species that live in cooler more temperate climates, provided adequate dry bedding and cover is available (Kingston 1998). Species from more arid regions, such as bilbies, should be provided with a heat lamp if held in temperate regions and allowed to retreat from the heat in hot weather.

4.7 Substrate Bandicoots and bilbies should ideally be maintained on sand or soil, though other substrates, including leaf litter, have been used. In all cases the substrate should be well drained and non-compactable (Kingston 1998). The presence of soil or sand allows bandicoots to dig nesting

From Mackerras and Smith (1960), McCracken (1986), Williams (1990), Kingston (1998) and personal observations

areas and forage for invertebrates. Bilbies in particular should be provided with sand, and/or soil, in which to dig.

4.8 Nest boxes Nest boxes should be provided. Boxes with dimensions 35 × 24 × 24 cm have been used successfully for Isoodon and Perameles (Lyne 1982). Nest boxes of 40 × 40 × 40 cm have been used successfully with bilbies (Hulbert 1982). They should be filled with a nesting material such as hay or straw.

4.9 Enclosure furnishings Various enclosure furnishings should be supplied, including grass tussocks and sedges, eg Lomandra longifolia, hollow logs, branches of eucalypts laid on the ground (especially in corners), large pieces of bark and nest boxes. Fresh grass or hay should also be supplied to assist in nest building (Krake and Halley 1993).

5. General husbandry 5.1 Hygiene and cleaning Each enclosure should be cleaned every one to two days to remove faecal matter and uneaten food. Small enclosures can be spot cleaned daily and given a full substrate clean weekly or more often if required. Drinking water dishes should be cleaned daily and water bottles should be checked daily to make sure the nozzle is working properly and that the bottle is at least two-thirds full. When an enclosure is emptied it should be scrubbed out prior to new animals being installed.

5.2 Record keeping A good record keeping system is important so that the health, condition and reproductive status of the captive bandicoot population can be monitored. Records should be kept of:

Bandicoots

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■ ■ ■ ■ ■ ■ ■

■ ■

Identification numbers; all individuals should be identifiable Any veterinary examination conducted Treatments provided Behavioural changes or problems Reproductive behaviour or condition Weights and measurements Changes in diet Movements of individuals between enclosures or institutions Births, with dam and sire if known Deaths with post mortem results.

The collection of information on physical and behavioural patterns of each individual can contribute greatly to the husbandry of these species. It also allows the history of each individual to be transferred to other institutions if required and greatly facilitates a cooperative approach to data collection amongst institutions. In most of the larger institutions ARKS (for general information on births, transfers and deaths), SPARKS (breeding studbook for species) and MedARKS (veterinary information) are used. These systems have been developed by the International Species Information System (ISIS), which is part of the Conservation Breeding Specialist Group (CBSG) software. As these are standardized, there is a high degree of efficiency in transferring information between institutions.

5.3 Methods of identification 5.3.1 Passive Integrated Transponder (PIT) tags These are implanted between the scapulae of individuals and can be used on all bandicoots. This is an excellent method of identification, however it can be expensive if many animals are implanted. PIT tags are a permanent method of identification but take care when they are implanted as they may track out along the injection site. This may be avoided by sealing the entry wound with tissue glue (Vetbond®) or similar fast setting adhesive. In some species, such as the northern brown bandicoot, the skin tears easily so the PIT tags can be implanted using a scalpel and needle while the bandicoot is under anaesthetic. A small hole is cut in the shoulder region to allow the insertion of the tag needle, after which the hole is sutured with 2–3 stitches (eg blue monofilament polypropylene – Ethicon Metric 2 with cutting KS 60 mm needle) (Gemmell pers. comm.). A disadvantage of the use of PIT tags is that they generally require the animal to be caught to confirm identification with a PIT tag reader.

5.3.2 Ear tattoos Tattooing is a frequently used technique for the identification of bandicoots, due to the large, thinly furred ears in many species (Isoodon has small dark ears). During this process care needs to be taken to avoid hitting any blood vessels inside the ear. The letters or numbers should be placed centrally and aligned with the bottom edge of the ear. Tattooing can be done using pliers but is best done with a tattoo pen while the animal is being restrained or anaesthetized (J. Seebeck pers. comm.). 5.3.3 Ear tags Metal ear tags have been used, however these have usually been unsatisfactory as they are often lost within several months (Lyne 1982). Fingerling ear tags have successfully been used on bilbies in captivity (K. Johnson pers. comm.). If using them, take care to avoid veins when making the hole through the ear. These are no longer recommended as they pull out causing ear damage and the sites can easily become infected (J. Seebeck pers. comm.). 5.3.4 Ear notching Although not generally used on adults, ear notching of pouch young has been used for identification (Lyne 1982). It is not recommended because it damages the ears (J. Seebeck pers. comm.).

6. Feeding requirements 6.1 Captive diet 6.1.1 Isoodon Ad Lib Water Daily Diet (per animal) 1 -- cup Mixed seed 4 5 g Apple, banana or paw paw 1 Mushroom 5 g Mung bean sprouts 5 g Alfalfa sprouts 1 -- cup Sweet potato 4 2 tbs Dog kibbles Supplements Weekly – 5–6 crickets, fly pupae, mealworms, moths, earthworms, grasshoppers or cockroaches. Sprinkle food with calcium powder such as DCP (dicalcium phosphate).

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Fruits including apple, banana, kiwi fruit, carrot, sweet potato and corn.

found their teeth were worn almost to the gum line (Gamble and Blyde 1992).

* Diet used by Taronga Zoo.

6.1.2 Perameles Ad Lib Water Daily Diet (per animal) 50 g Eukanuba® Pet Food Kibble 5 g Apple 5 g Banana 1 -- Egg 4 3–4 Dog kibbles 1 -- tsp Fly pupae 4 1 tsp Mealworms 1 tsp Earthworms Supplements Weekly 5–6 crickets or moths Fruits including apple, banana, kiwi fruit, carrot, sweet potato and corn.

6.3 Presentation of food Most of the food is supplied in a dish; however, live food is best provided by being scattered around the enclosure to promote foraging behaviour.

7. Handling and transport 7.1 Timing of capture and handling Capture and handling is best undertaken during the day, or just before the lights go on in a nocturnal house, when the bandicoots are in their nest or nest box.

7.2 Catching bags Large calico bags and strong good quality pillowcases (otherwise they will be easily ripped by the animals’ feet) are useful in holding bandicoots and depending on the species should be 40–60 cm deep or 30–40 cm deep.

* Diet used by Healesville Sanctuary.

6.1.3 Macrotis Ad Lib Water Daily Diet (per animal) 1 -- cup Mixed seed 4 5 g Apple 5 g Banana 5 g Mung bean sprouts 5 g Alfalfa sprouts 5 g Paw paw 3–4 Dog kibble 1 tsp Mealworms 1 tsp Earthworms Supplements Weekly – 5–6 crickets, fly pupae, moths, grasshoppers or cockroaches. Fruits including apple, banana, kiwi fruit, carrot, sweet potato and corn. * Diet used by Taronga Zoo.

A simple alternate diet that has been used to successfully maintain bilbies uses dog kibble and budgie seed mix (K. Johnson pers. comm.).

6.2 Supplements Di-Vetelact (125 g powder and 900 ml water) has also been used to increase the weight of aged bilbies. They were given 50 ml in a bowl to gain weight after it was

7.3 Capture and restraint techniques Larger species such as bilbies are generally readily caught from their nest box, often simply by placing a bag over them and scooping them up. If the animal to be caught is out in the enclosure, a strong cotton net approximately 60 cm deep and 45–50 cm wide can be used to scoop them up easily. If the bandicoot is in a depression (which is usually thin and long) its location can generally be identified by a slight bulge at the base of a tussock or other area where you know from experience they nest. Different techniques can be used, usually involving two people, but with practice one person can capture them. If two people are present, one holds a net over one end of the nest, with the bottom of the net touching the ground in case the bandicoot shoots out. The second person squats to the side or other end of the nest and places firm pressure along the top of the nest with one hand, while keeping the end of the nest away from the net holder closed with the other hand (by using firm downward pressure), while also feeling inside the nest to find the rump. If it is the wrong end you may have to both re-position (while still maintaining firm hand pressure on the nest). When the rump end is found, firm pressure is sustained on the shoulders and forehead region with one hand and the other hand moves along the back (from the rump) until the animal is gripped over the shoulders. The hand that was maintaining pressure over the shoulder and head region is then placed over the rump region and the

Bandicoots

holding the animal, making sure to cover the eyes, while someone else checks the areas of interest. Normally only the area to be examined is pulled out of the bag while the rest of the animal stays securely inside the bag. Pouch checking and other examinations should be undertaken in an enclosed space and with the animal in a catching bag to keep the eyes covered (they tend to try and escape if they can see). One or more people can carry out the examination in an enclosed space while sitting down and with several nets nearby. If doing the examination alone, sit in a chair or squat against a wall and place the bag in your lap with the animal on its back with its head facing away from you and covered and gently squeeze its body to help restrain it (Kingston 1998). Once it is in this position, you can examine the front – the head, ears and front feet. Turn the animal with its head facing away from you to examine the pouch and hind-quarters (Kingston 1998). The pouch can be examined by pulling the legs apart with the outer part of your hand and opening it gently. Figure 1. Handling technique used for bandicoots. Photo by Stephen Jackson.

animal can be picked up (Fig. 1). With practice, one person can carry out this technique, but two people should be present wherever possible. If the bandicoot escapes into the enclosure then it should be netted as soon as possible. They tend to run very rapidly and jump up the walls, which can result in injury. Care also needs to be taken to ensure that pouch young have not been thrown when catching females that might have a pouch young. Ideally, females with large pouch young should not be caught up. Once caught, bandicoots are best transferred to calico bags for examination. When their eyes are covered they stop kicking, resulting in less fur loss, more control and less stress. However, if required, they can be held firmly between the index and middle fingers of one hand, in a similar method to that used for possums and rodents. The other hand holds the rump, with the tail held between the index and middle finger or middle and fourth finger (Fig. 1). Never hold the tail as it may fall off (J. Seebeck pers. comm.). However, unlike Perameles and Isoodon, you can readily hold bilbies by the tail (K. Johnson pers. comm.).

7.5 Release As most species of bandicoots are very flighty and will often run around the enclosure and jump up the walls and/or climb the walls after release, it is often easier to place the bandicoot in a transport box or catching bag. Once it has settled down in the box or bag, it is then placed on the ground in the enclosure so the animal can emerge in its own time. Bilbies generally handle being released much better and can be released into a nest box or open enclosure. In either case, the enclosure should be as free as possible of obstacles to minimize the opportunity for the animal to run into any of them.

7.6 Transport requirements 7.6.1 Box design Strongly built boxes with sliding doors are recommended. It is important to have adequate ventilation holes and to ensure they do not get blocked during transport. Other considerations for box design include carrying handles and spacer bars on the outside to allow ventilation. Boxes are best made from 7 mm plywood and 15 × 15 mm pine framework (Kingston 1998). Further specific details of the box design can be found in IATA (1999).

7.4 Weighing and examination Weighing is easily undertaken with spring or balance scales. General examination can be done under anaesthetic or over a short period with one person

7.6.2 Furnishings Nesting material such as shredded paper or barley hay should be provided.

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7.6.3 Water and food Water and food are normally not required during travel, as the animals usually do not eat it. On longer journeys, food items high in water such as apples, grapes or pears could be offered (Kingston 1998). 7.6.4 Animals per box One per box; females with pouch young should not be transferred unless young have only recently been born and are still attached to the teat. 7.6.5 Timing of transportation Ideally, animals should be transported overnight or in the cooler part of the day, although not too cold (eg between 10 and 20°C). If hot, they should be transported in an air-conditioned vehicle. 7.6.6 Release from the box Most species of bandicoots are very flighty so take care when releasing them. Generally, the best way to release them is to gently place the box on the ground, remove or fully open the box door and leave the enclosure to allow the bandicoot to emerge from the box in its own time. Bilbies generally cope with being handled quite well and often respond to being released, even by hand, by digging and ambling around the enclosure.

8. Health requirements Edited by Dr Rupert Woods

8.1 Daily health checks Each bandicoot should be observed daily for any signs of injury or illness, especially after they have been introduced, as they often show aggression towards each other. The most appropriate time to do this is generally when the enclosure is being cleaned or when they are being fed as many of the larger species, especially in nocturnal houses, will approach to be fed. At this time, each animal in the enclosure should be checked and the following assessed:

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8.2 Detailed physical examination 8.2.1 Chemical restraint Pre-anaesthetic fasting is not necessary for adult animals as they are not prone to regurgitation (Vogelnest 1999). Hand-reared animals however should not be fed for at least one hour before anaesthesia as they may regurgitate the milk formula (Vogelnest 1999). Animals can be sedated using intramuscular diazepam (Valium®) (0.5–1.0 mg/kg) (Vogelnest 1999). Anaesthesia is best undertaken by inhalation as bandicoots are readily handled and induction with a conical face mask is easy. Some bandicoots may breath hold if induced by mask so it may be preferable to use an induction chamber after sedation, intramuscular diazepam (Valium®) works well (R. Woods pers. comm.). Isoflurane in oxygen is preferred, although 5% flurothane in oxygen using a Fluotec nebuliser has also been used successfully (Vogelnest 1999). Intubation is easy using a bladed laryngoscope and a 2 mm uncuffed endotracheal tube. Induction and recovery are rapid and muscle relaxation excellent (Vogelnest 1999). Injectable agents are rarely used (Booth 1994). 8.2.2 Physical examination If bandicoots are being caught up and examined, look for wounds. The presence of open wounds or lumps throughout the body, especially around the face and rump, suggests aggression problems. Also check the eyes closely for cloudiness and general clarity. Body weight is also a useful indicator of condition. The physical examination may include the following: ■

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■

■ ■ ■ ■

Coat condition – in particular, fur missing around the rump Discharges – from the eyes, ears, nose, mouth or cloaca Appetite Faeces – number and consistency Eyes – for cloudiness Changes in demeanour

Presence and development of pouch young by observation of the bulge in the pouch Injuries

■

Body condition – best assessed by muscle palpation in the area over the scapula spine and temporal fossa. Temperature – normally 33–34°C (average 33.5°C) (Meritt 1970); can be taken through the anus via cloaca. Weight – record and compare to previous weights. Trends in body weight of bandicoots give a good general indication of the animal’s state of health, provided age, sex and geographical location are taken into account. Animals in captivity should be weighed monthly to indicate trends. Pulse rate – varies greatly with the species, with rate decreasing with increasing body size; taken over the femoral artery.

Bandicoots

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■

Respiratory rate – normally 31–37 (average 34) breaths per minute at rest (Meritt 1970) but varies greatly across species, the rate decreasing with increasing body size. Fur – check for alopecia, ectoparasites, fungal infections or trauma. Eyes ➝ Should be clear, bright and alert ➝ Normal bilateral pupillary light response ➝ Normal corneal reflex ➝ Should not have any discharges Also check for the presence of lumps over body and auscultation of lungs Cloaca ➝ Should be clean ➝ Check for faeces around the cloaca Pouch ➝ Condition of the pouch ➝ Check whether lactation is occurring by milking teats ➝ If pouch young are present, record sex, stage of development, weight if detached from the teat and measure to determine age from growth curves if available Males ➝ Check testes – size (length, width, depth) and consistency (firm – not squishy) ➝ Extrude penis and assess ➝ Check the size and activity of the sternal gland.

8.3 Known health problems Bandicoots generally suffer from few health problems associated with disease, with most animals generally dying from old age or aggression (Williams 1990). The majority of the parasites and diseases that have been recorded are presented in the following section. 8.3.1 Ectoparasites Cause – Bandicoots are host to various ectoparasites including fleas (Pygiopsylla spp.), ticks (Ixodes spp. and Haemaphysalis spp.), mites (Odontacarus spp. and Haemolaelaps spp.) that can occur in seasonal infestations, especially during the warmer months of spring and summer (Lenghaus et al. 1990; Thomas 1990; Booth 1994). Signs – Large numbers of parasites throughout the fur and face. Juvenile bandicoots may suffer from a reduced growth rate and increased white blood cell count compared with bandicoots that are tick free (Gemmell et al. 1991).

Diagnosis – Generally by visual signs and skin scrapings for mites with microscope examination to identify the parasites. Treatment – Ticks and fleas can be treated with an insecticidal wash (Malawash®, ICI Australia), diluted as recommended and given every 14 days (Presidente 1982). Ticks can also be removed manually. Mites can be treated with a topical acaricide in mild cases using three or four treatments of 1.25% solution of amitraz (Demadex®, Delta Laboratories) at weekly intervals. Prevention – Continual monitoring, especially if the animals are in a natural habitat enclosure. Change the bedding regularly. 8.3.2 Endoparasitic worms Cause – Bandicoots are infested with various endoparasites. Roundworms such as Labiobulura spp., Physaloptera spp., Strongyloides spp., and Moniliformis spp. have been found in bandicoots. If burdens of 20–50 are present, they can cause severe ulcerative granulomatous gastritis sufficient to cause debility (Lenghaus et al. 1990). Various cestodes, nematodes including Nicollina spp., Asymmetracantha spp. Austrostrongylus spp., Mackerrastongylus spp., Parastrongyloides spp., Peramelistrongylus spp. and Trichurus spp. and trematodes have been found in bandicoots though the significance was not stated (eg Mawson 1960; Obendorf and Munday 1990). Signs – Not obvious unless diagnosed. Diagnosis – Faecal flotation and the presence of eggs or proglottids (segments that make up the worms). Treatment – Usually treated with ivermectin (Ivormec®) at 400 ug/kg by mouth as a single dose or Panacur® 2.5 (25 mg/ml fenbendazole) at 50 mg/kg by mouth daily for three consecutive days (Kingston 1998). Prevention – Generally not required but could be by routine treatment with anthelminthics. It is also important to remove faeces from the enclosure and to maintain good hygiene. 8.3.3 Protozoans Cause – The protozoan Toxoplasma gondii has caused deaths in both wild and captive bandicoots (Pope et al. 1957; Obendorf and Munday 1990; Kingston 1998). Bandicoots become infected as a result of ingesting sporulated oocytes contaminating food, soil and invertebrate paratenic hosts. They can come into contact directly as a result of soil or plant matter put in their enclosure or secondarily via earthworms that have ingested some of the oocysts in the soil (Obendorf and Munday 1990; Bettiol et al. 2000a). Eastern-barred

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bandicoots have died within 11–14 days from toxoplasmosis after eating infected worms (Bettiol et al. 2000b). Signs – Can cause cataracts and retinal disease, incoordination, apparent blindness, erratic staggering movements, unnatural daytime activity and death (Obendorf and Munday 1990). Diagnosis – Ante mortem diagnosis of toxoplasmosis is confirmed by serological testing to detect rising IgG Toxoplasma gondii titres. Direct Agglutination Test or Modified Agglutination Test using the commercial kit Antigene Toxo-AD and microtiter plate reagents (bioMerieux SA, Marcy l’Etoile, France) are useful (Bettiol et al. 2000a; Miller et al. 2000). The agglutination tests as outlined by Desmonts and Remington (1980) have been used to monitor the development of specific T. gondii antibodies. Treatment – Once infected, individuals usually die (Obendorf and Munday 1990). Could potentially medicate with anti-protozoal drugs such as sulphonamides including amprolium; toltrazuril can be used to treat coccidiosis (Booth 1999). Prevention – Keep all bedding material and food away from cats. 8.3.4 Trauma Cause – Trauma is the most common reason for treatment in captive eastern-barred bandicoots (Kingston 1998). It can result from aggression by other individuals, from climbing up the walls or running into obstacles, especially during capture or transport. Signs – Fur loss especially around the rump or damage to the eyes and face is often caused by other animals. Climbing the walls of the enclosure may cause injuries to toes and other trauma. Diagnosis – Through clinical signs and radiography. Treatment – Depends on the injury sustained. Prevention – Great care needs to be taken when introducing bandicoots into enclosures. Mixing animals of similar size may result in less aggression as will introducing animals into larger enclosures. Enclosure walls should have a tin skirting about 1.5 m high to decrease the opportunity of climbing up them.

9. Behaviour 9.1 Activity All species of bandicoots are primarily nocturnal (Heinsohn 1966). Observations in captivity have shown bilbies to have a number of activity phases, usually of

several hours duration (Aslin 1982). Species such as eastern-barred bandicoots are frequently seen in paddocks after emergence at dusk until several hours before sunrise, whereas southern brown bandicoots prefer more covered habitat (Heinsohn 1966). In captivity, observations of southern brown bandicoots in nocturnal conditions showed them to spend 36% of the time in the nest, 28% stationary, 16% moving, 9% digging, 4% grooming, 3% standing upright, 3% feeding, and 1% wall running (Garling 1982).

9.2 Social behaviour 9.2.1 Isoodon Southern brown bandicoots are solitary and appear to be strongly territorial (Heinsohn 1966). In captivity this species is usually very aggressive towards each other. One animal will often dominate and attack another one which usually does not defend itself but crouches and exposes its rump to the attacker (Heinsohn 1966). In captivity male southern brown bandicoots have been observed to attack and kill females (Heinsohn 1966). Females will sometimes attack males, which may be due to their relatively larger size or because they are introduced into a foreign territory (Heinsohn 1966). Therefore animals should be introduced that are of similar size. Northern brown bandicoots have been kept successfully with one male and several females (R. Gemmell pers. comm.). Although these species are generally not considered to dig burrows (Heinsohn 1966), a captive brown bandicoot has been observed to dig a burrow (Kirsch 1968). 9.2.2 Perameles Wild eastern-barred bandicoots are promiscuous (Dufty 1994a). They demonstrate very little social behaviour, use mutual avoidance and feed separately, though they will occasionally chase each other and make snorting sounds and there appears to be a dominance hierarchy (Heinsohn 1966; Dufty 1994a). Wild eastern-barred bandicoots use rabbit warrens. Animals displace other bandicoots from their nests (Heinsohn 1966). Eastern-barred bandicoots do not have fixed home nests but use whatever they can find and observations on captive animals showed pairs to generally nest apart, although they will nest together, and will abandon the nest if disturbed and build another one in a different location (Heinsohn 1966). The nests can be either a shallow depression in the soil about 10 cm deep under thick shrubbery or in grass that covers a lined shallow depression (Heinsohn 1966). Other captive observations suggest that there is a hierarchy in both male and female

Bandicoots

eastern-barred bandicoots. They can show significant aggression towards each other, especially in a confined space and, as a result, are generally held separately. Observations of captive male eastern-barred bandicoots show them to be highly aggressive with a male chasing a second male continuously after it was introduced over four nights until it was removed (Heinsohn 1966; Seebeck (1979). Similar observations were made when long-nosed bandicoots were introduced to each other, which resulted in one of them eventually dying from injuries inflicted by the other male (Stodart 1966). Sex ratios that have been used successfully with eastern-barred bandicoots (and which should be adequate for other species) include 1:1, 0:2 and 1:2 (Krake and Halley 1993). 9.2.3 Macrotis Groups of bilbies can be maintained in captivity without serious fighting, with aggressive behaviour seldom being observed (Aslin 1982; Johnson and Johnson 1983; pers. obs.). Bilbies have proved to be relatively passive in captivity in comparison with other bandicoots, and a rigid dominance hierarchy amongst males is usually maintained without serious fighting (Johnson and Johnson 1983). When aggression occurs it usually consists of one animal directing loud threat hisses at another, which usually retreats immediately (Aslin 1982; Johnson and Johnson 1983). If the second animal does not retreat it generally results in the two circling one another briefly nose to tail and hissing loudly and on rare occasions this is followed by one animal leaping on the other attempting to bite its rump or flank, which results in fur loss (Aslin 1982). Unlike other bandicoots that generally excavate only shallow depressions in which to nest, the bilby digs deep spiral burrows (Aslin 1982; Johnson and Johnson 1983). Dominant males chased subordinate males out of and away from burrows and the alpha male maintained priority of access to all the well-used burrows in the enclosure, which was assisted by scent marking them (Johnson and Johnson 1983). Males shared burrows freely with females (at which time their ears normally fall down due to decreased blood flow; pers. obs.) and copulation appears to take place in the burrow (Aslin 1982; Johnson and Johnson 1983; pers. obs.). Females also appear to have a less intense hierarchy and will share their burrows with each other (Johnson and Johnson 1983).

9.3 Reproductive behaviour Reproductive behaviour appears to be fairly consistent between the different species of bandicoots. It involves

the male following the female for up to several hours, sniffing her rump and making numerous attempts to mount her (Stodart 1977; Coulson 1990). Mating attempts can be as short as three to seven seconds but can be up to 30 seconds or longer (Heinsohn 1996). During mating attempts, the male rests his head on the female’s back and grips her with his forelegs. Copulations are rapid and may be repeated intermittently for up to 45 minutes (Dufty 1994a).

9.4 Bathing Bandicoots are not known to bathe although they have been observed splashing through shallow puddles (J. Seebeck pers. comm.).

9.5 Behavioural problems The major behavioural problems of bandicoots are aggression and cannibalism by females of their young. Both these behaviours appear to be greatly lessened by increasing the size of the enclosure. Stereotypic behaviour of southern brown bandicoots has been observed; however it did not occur frequently and may have been due to the keepers walking past (Garling 1982). Major aggression problems are rare in bilbies (K. Johnson pers. comm.).

9.6 Signs of stress Signs of acute stress include escape attempts. Bilbies tend to hiss while other species tend not to vocalise (Spielman 1994). Acute stress generally results in reduced food intake, reduced weight, poor coat condition and alopecia (Spielman 1994). Bilbies, especially females after raising young, can experience hair loss. This does not appear to debilitate them although it does not look good for exhibit (K. Johnson pers. comm.).

9.7 Behavioural enrichment Various behavioural enrichment activities can be provided for bandicoots in captivity. These include: ■

■

■

Providing appropriately deep substrate to allow animals to dig nests and forage Providing live food throughout the enclosure, to promote foraging behaviour Providing fresh tussocks and branches to nest under

9.8 Introductions and removals When pairs of eastern-barred bandicoots are first introduced they will generally take a little time to settle down. Males will initially chase females, but after several days they will often nest together (Heinsohn 1966).

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Table 5. Social behaviour of bandicoots and the suggested sex ratio of different genera when held in captivity. Genus

Social Behaviour

Suggested Sex Ratio

Isoodon

Solitary

Solitary or 1:1

Perameles

Solitary

Solitary, 1:1, 1:2 or female pairs

Macrotis

Solitary/Can nest together?

1:1 – 1:2

introduced, that the enclosure is as large as possible and that they are monitored, at least initially, for signs of aggression.

9.10 Interspecific compatibility

Peramelidae

Significant aggression has been observed with a male scaling a partition and biting and scratching a female on the other side, partly mutilating her ear, scratching her back and rump and tearing out large patches of fur. After being separated they were later re-introduced and were compatible (Heinsohn 1966). Similar aggression has been observed in southern brown bandicoots, where both males and females are aggressive to members of the same or opposite sex, which can result in death from injuries sustained (Heinsohn 1966). Given the dominance hierarchy that exists, it is best to place the larger animal into the small animal’s established enclosure rather than the other way around. With this in mind, successful introductions appear to be those where the body size of the individuals is similar (Stoddart and Braithwaite 1979). To assist in the introduction there should be at least two to three nest areas per individual and once introduced, daily checks should be made if possible to check for signs of aggression such as fur, blood or an animal out in the open. Other considerations include making sure there is adequate cover, feed stations (one each and widely separated), and make sure the enclosure is not overcrowded (Kingston 1998). Southern brown bandicoots require a large area, and it is important to choose animals of a similar size otherwise the smaller one may be maimed or killed (Mackerras and Smith 1960). A method used to successfully introduce a captive bandicoot to a group, and reduce fighting, is to remove all bandicoots and place them in a new enclosure with the newcomer (R. Gemmell pers. comm.).

9.9 Intraspecific compatibility Most species of bandicoots are generally unsocial and frequently highly aggressive if placed with their own sex. Species within the genera Perameles and Isoodon are usually high aggressive to one another and so should be kept either by themselves or in pairs. In contrast, the bilby is comparatively tolerant of other individuals and can readily be kept in pairs or small groups (Table 5). It is very important that animals of similar size are

Bandicoots have been held with various species of other animals, especially arboreal species such as yellow-bellied gliders Petaurus australis, sugar gliders Petaurus breviceps, squirrel gliders Petaurus norfolcensis, Leadbeater’s possums Gymnobelideus leadbeateri, common ringtail possums Pseudocheirus peregrinus, common brushtail possums Trichosurus vulpecula and brush-tailed phascogales Phascogale tapoatafa (Garling 1982; Krake and Halley 1993; pers. obs.). Bilbies have been held with other terrestrial mammals including mulgara Dasycercus cristicauda (Lee 1990).

10. Breeding 10.1 Mating system All species of bandicoots appear to exhibit a polygynous mating system.

10.2 Ease of breeding Bandicoots generally breed well in captivity and a number of species, if not all, will re-enter oestrus if the young are lost. Long-nosed bandicoots, for example, re-entered oestrus as early as five to 10 days (Close 1977).

10.3 Reproductive status 10.3.1 Females Bandicoots are generally placed in several categories depending on their reproductive status. Females can be categorized into several reproductive stages including: ■

■

■

■

■ ■

Non-parous (females that have never bred) – pouch small with no skin folds, clean and dry, teats very small Parous (females that have bred previously but not presently) – pouch is small but distinct, dry and dirty, the teats are slightly elongated Oestrus – the female’s urogenital opening changes with swelling of the lips, which corresponds with the presence of cornified epithelial cells (Lyne 1976) Pregnant – Pouch pink in colour and glandular in appearance, skin folds may be observed on the lateral margins of the pouch Pouch young present – attached to the teat Lactating (young absent from the pouch but still suckling) – pouch area large, skin folds flaccid, hair

Bandicoots

■

sparse and stained, skin smooth and dark pink, teats elongated Post lactation with teats expressing only clear liquid and/or regressing.

If pouch young are present, a number of developmental stages and measurements can be recorded and compared to existing growth curves (See Section 10.16), or new curves established for future reference. These include: Developmental stages ■ Sex distinguishable ■ Tips of ears free ■ Papillae of facial vibrissae evident ■ Eyelashes visible ■ Eyes open ■ Fur visible – slight tinge, medium or well developed ■ Tips of first incisors through the gums ■ At foot ■ Eating solids ■ Self feeding ■ Independent Measurements (see Appendix 5) ■ Weight (g) – if not on teat ■ Head length (mm) – from the occiput to snout tip ■ Head width (mm) – maximum width across the zygomatic arches ■ Crown rump length (mm) – primarily for neonates ■ Body length (mm) – from snout tip to cloaca ■ Tail length (mm) – from the cloaca to the end of the last vertebra of the tail tip ■ Total length (mm) – from snout tip to tail tip ■ Tibia length (mm) – from the hip to the bottom of the pes ■ Pes length (mm) – from the heel to the base of the longest toe, not including the claw. 10.3.2 Males Sexual maturity of male northern brown bandicoots (where sperm first appears in the reproductive tract) corresponds with pigmentation of the scrotum, though these signs precede sexual maturation by at least 150 days and are not good indicators of reproductive ability in male bandicoot (Gemmell 1987).

10.4 Techniques used to control breeding Although the detection of cornified epithelial cells has been used as a technique to determine oestrus in bandicoots (Lyne 1976), it is not generally necessary due to the ease with which most species breed. Further information on this technique is given in Chapter 3. The

male can generally be left in with the female after mating without adverse affects on the female or young. Although many species of bandicoots appear to breed almost continuously throughout the year, some species of bandicoots show evidence of annual cycles in their reproductive activity with peaks in spring and early summer. Environmental variables of day length, rainfall and temperature were assessed and it was discovered that reproduction was most related to the rate of change in minimum temperature, although there were additional associations with rainfall and day length (Barnes and Gemmell 1984). Other observations of captive animals have suggested that day length may influence breeding activity because captive, well-fed, northern brown bandicoots were not continuous breeders (Gemmell 1982). Therefore, the manipulation of these factors could potentially increase reproductive output in captivity. To maximize breeding success in eastern-barred bandicoots, breeding pairs are usually kept together continuously and juveniles are removed after 10–12 weeks (Krake and Halley 1993).

10.5 Occurrence of hybrids None known to occur.

10.6 Timing of breeding Most species of bandicoots can breed throughout the year, although there may be a peak during spring and summer, when food availability is greatest. The northern brown bandicoot, for example, can produce young at all times of the year but is more likely not to produce young between February and July (R. Gemmell pers. comm.). The western-barred bandicoot is known to have a distinct breeding season between March and April (Table 6). Eastern-barred bandicoots demonstrate a reproductive shutdown in winter in Tasmania, but breed throughout the year in Victoria. They are affected by climatic conditions and will shut down over summer, particularly if rainfall is below average (J. Seebeck pers. comm.).

10.7 Age at first breeding and last breeding Bandicoots reach sexual maturity quickly with species such as south brown bandicoots being able to breed in only 3.5 to four months after birth and all other species (for which it is known) being able to breed within 250 days (Table 6). Climatic conditions appear to be important in allowing breeding as female eastern-barred bandicoots have been found to delay sexual maturity by

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Table 6. Reproduction and development for different species of bandicoots. Species

Isoodon macrourus Isoodon obesulus Perameles bougainville Perameles gunnii Perameles nasuta Macrotis lagotis

Litter Size (mean) 1–7 (2.7) 1–6 (2.5) 1–3 (2.5) 1–5 (2.5) 1–5 (2) 1–2 (1.5)

First Detach (d) 42

Permanent Pouch Exit (d) 55

55 50–54 67–82

Weaning (d) 60 60–70

Sexual Maturity M (m) 350 120

70–75 62–63 90

120–150 150 270–420

Sexual Maturity F (m) 250 90–120 90–150 75–105 120 175–220

Mating Period

Ref.

All year All year Mar–Nov All year All year All year

1, 2, 3, 4, 5, 6, 7, 8 9, 10, 11, 12, 13 14 10, 15, 16, 17 9, 18 19, 20, 21

References: 1 Mackerras and Smith 1960; 2 Gemmell 1982; 3 Gemmell et al. 1984a; 4 Gemmell 1986; 5 Gemmell 1987; 6 Gemmell 1988a; 7 Gemmell 1989a; 8 Friend 1990; 9 Lyne 1964; 10 Heinsohn 1966; 11 Stoddart and Braithwaite 1979; 12 Lobert and Lee 1990; 13 Mallick et al. 1998; 14 Short et al. 1998; 15 Dufty 1991; 16 Dufty 1994b; 17 Kingston 1998; 18 Stodart 1966; 19 McCracken 1986; 20 McCracken 1990; 21 Southgate et al. 2000.

up to six months under bad drought conditions (J. Seebeck pers. comm.). In captivity bandicoots can generally breed until shortly before they die and bilbies have been known to breed until more than four years of age (Southgate et al. 2000).

10.11 Breeding diet The amount of food supplied can be slightly increased towards late lactation and increased further if all the food is being eaten.

10.12 Oestrous cycle and gestation period

10.8 Ability to breed every year Bandicoots can breed every year. Northern brown bandicoots can produce up to four litters per year, with an average interval between litters of 90 days (range 51–108) (Friend 1990; Kemper et al. 1990). Similar observations have been made on eastern-barred bandicoots, which show they produce an average of 3.8 litters per season (Heinsohn 1966). Southern brown bandicoots can have up to four litters per year (Copley et al. 1990; Lobert and Lee 1990), as can bilbies (Southgate et al. 2000). One of the techniques that bandicoots appear to use to achieve this is by using an alternative nipple strategy, where young attach to up to half the teats for one litter and the other teats for the second litter (Heinsohn 1966).

10.9 Ability to breed more than once per year All species of bandicoots appear to be able to breed more than once per year.

10.10 Nest/hollow requirements Nest boxes and grass tussocks should be provided, as outlined in Section 4.8.

Bandicoots have relatively short oestrous cycles that typically last 12–37 days. Their gestation periods are close to the shortest known of any mammal group, and typically range from 12.5 to 14 days (Table 7). When born, the neonates are very unusual among marsupials in that they have a placenta that can be seen stretched between the cloaca and the pouch. Bandicoots (and the koala) have a chorioallantoic placenta very similar to eutherian or placental mammals, whereas other marsupials have a less invasive placenta called a choriovitelline placenta (Tyndale-Biscoe and Renfree 1987).

10.13 Litter size The litter size of bandicoots decreases with the age of the young, eg northern brown bandicoot litters can be as high as seven at birth and decrease to the time of weaning (Gemmell et al. 1984b; Gemmell 1989b). The loss of pouch young occurred throughout pouch life and there was no obvious period of highest risk (Gemmell 1989b). In eastern-barred bandicoots, litter size appears to vary with season and age; females may begin with a small litter and have larger ones as they mature (J. Seebeck pers. comm.).

Table 7. Duration of oestrous cycle and gestation (days) for bandicoots. Species

Oestrous Cycle

Gestation

Diapause

Ref

Isoodon macrourus

14–30 (22)

12.5

N

1, 2, 3

Perameles nasuta

17–34 (26)

12.5

N

3, 4, 5, 6, 7, 8

Macrotis lagotis

12–37 (21)

13–16 (14)

N

8, 9

References: 1 Lyne 1974; 2 Lyne 1976; 3 Gemmell 1988b; 4 Hughes 1962; 5 Lyne 1964; 6 Stodart 1966; 7 Close 1977; 8 McCracken 1986; 9 McCracken 1990. Numbers in brackets are mean values.

Bandicoots

Table 8. Growth curve measurements that have been developed for different species of bandicoots. WT – weight, CR – crown to rump length, EA – ear length, HB – head-body length, HE – head length, LE – leg length, MA – manus length, PE – pes length, TA – tail length. Common Name

Measurements

Reference

I. macrourus

WT, CR, HB, HE, PE, TA

1, 2, 3, 4, 5, 6

I. obesulus

WT, EA, HE, PE, TA

7, 8, 9

P. gunnii

WT, CR, EA, HE, PE, TA

2, 7, 8, 10

P. nasuta

WT, EA, HE, MA, PE, TA

11

M. lagotis

WT, HE

12, 13, 14

References: 1 Mackerras and Smith 1960; 2 Collins 1973; 3 Gemmell et al. 1984a; 4 Hall 1990; 5 Gemmell and Hendrikz 1993; 6 Attard and McKillup 1998; 7 Heinsohn 1966; 8 Austin 1997; 9 Hale 2000; 10 Dufty 1995; 11 Lyne 1964; 12 Hulbert 1972; 13 McCracken 1990; 14 Southgate et al. 2000.

the growth and development of bandicoots are given in Table 8.

11. Artificial rearing 11.1 Housing As with all native mammals that have been taken into care, minimizing stress is a major consideration. Choosing suitable housing can help to create a stress free environment. To achieve this, several factors should be considered including: ■ ■ ■

It is important that once the young are born the female is not put in stressful situations, eg with excess noise or overcrowding, as most bandicoots (rarely, if at all, in bilbies) are known to be cannibalistic in captivity. Northern brown bandicoots, long-nosed bandicoots and eastern-barred bandicoots, for example, are known to kill and eat their young when stressed, which appears to be more common in small enclosures or if handled too frequently (Mackerras and Smith 1960; Lyne 1971; Lyne 1982; Gemmell 1989b; pers. obs).

10.14 Age at weaning Weaning in bandicoots is very quick as the young grow rapidly and the females breed almost continuously with often only several months between litters (Stodart 1966). In both captive and wild animals, the greatest losses are immediately after weaning (Gordon 1974; Hall 1983; Gemmell 1989b).

10.15 Age of removal from parents Young should be removed immediately after weaning as there is a high chance of inbreeding or aggression if they are left in the enclosure. Northern brown bandicoots can be removed after 60 days as they do not suckle and have no need of their mother (R. Gemmell pers. comm.). Eastern-barred bandicoots, for example, are removed at 10–12 weeks. This is particularly important in the case of young females, which reach sexual maturity in three to four months (Krake and Halley 1993; Table 6).

10.16 Growth and development The growth and development is known for several of the Australian species of bandicoots (Fig. 2). Graphs of most of these can be seen in Bach (1998). Further references on

■ ■

Securing the area from children and animals Maintaining the area in a hygienic manner Escape-proofing the area. Clearing the area of obstacles and hazards Ensuring the area offers shelter from weather and noise.

If possible, use a humidicrib or otherwise, a secure box. First, line the box with a towel, then supply a sock, beanie, ugg boot, jumper or windcheater for the juvenile to nest into (Austin 1997; Kingston 1998).

11.2 Temperature requirements The temperature is generally kept at 28–30°C (Austin 1997; Kingston 1998). Use a minimum/maximum temperature gauge with a plastic coated probe that can be placed next to the joey, as this will ensure that the temperature can be monitored (J. Cowey pers. comm.). Unfurred joeys will require external heating, which can be provided by a hot water bottle that is well wrapped up in towels, a heat lamp or heat pad, making sure the animal does not become overheated or too cold. Once fully furred, external heating is not necessary as long as the animals are kept clean and dry.

11.3 Diet and feeding routine 11.3.1 Natural milk The milk of northern brown bandicoots during lactation has been found to be similar to other marsupials with milk solids increasing from 8% to more than 40% over 55 days. Carbohydrate concentration increased from about 2% initially to 7% in mid lactation, declining to 1% in late lactation. Concentration of lipids reached 25% by 55 days, and protein increased from 2% to 14% in mid lactation and then to 2% in late lactation (Merchant and Libke 1988; Merchant 1990). Milk intake by pouch young increases from 2 ml per day after 20 days to 18 ml by day 55 (Merchant 1990). The concentrations of the major constituents are shown in Table 9.

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Table 9. Concentrations of major constituents of northern brown bandicoot milk. Species

Total Solids (%)

Carbohydrates (%)

Lipids (%)

Protein (%)

Calcium (mg/l)

Iron (mg/l)

80–400

10–70

20–250

20–140

–

–

I. macrourus

From Merchant and Libke (1988)

11.3.2 Milk formulas

■

The three main low lactose formulas for hand-rearing bandicoots are: ■

■

Wombaroo Kangaroo Milk – different formulas are used for the different stages of development to mimic the changes that occur in the female’s milk during lactation. Charts are provided to assist in determining the volume to be fed. Wombaroo 0.7 Kangaroo Milk Replacer has been used with good success (Kingston 1998). The formula is made up according to the instructions; with the cream content increased every two days until it is double the original strength, as bandicoot milk is higher in fats than kangaroo milk (Kingston 1998). There has been some suggestion that adding saturated fats in the form of cream can lead to the malabsorption of calcium (Smith no date). Therefore some groups advise the addition of mono and polyunsaturated fats such as canola oil rather than cream (Smith no date). Di Vetelact – is a low lactose milk formula that is widely used. Due to its low energy concentration when prepared as directed, some groups advise the addition of cream as with Wombaroo diets. This should be fed at approximately 20% bodyweight, except for very small joeys.

Biolac – the three formulas are M100 for furless joeys, M150, which is a transitional milk to feed when dense fur has developed, and M200, which contains elevated lipid in the form of canola oil and is used when the animal produces solid dark pellet droppings. When the joey is nearing weaning, 2–5 ml of canola oil is added per 100 ml of formula. Mixing the formulas is the way to make the transition from one formula to another. Animals should be fed 10–15% of their body weight per day.

11.3.3 Feeding apparatus Very small joeys can be fed using a syringe fitted with a bicycle tyre rubber valve, plastic intravenous catheter or 25 mm length of infant gastric feeding tube (Bellamy 1992). Larger joeys can be fed with a plastic feeder bottle, which comes in 50 and 100 ml sizes, and a special Type (b) teat (Austin 1997) or T4 Biolac teat. The teat should be punctured with a hot needle (A. Gifford pers. comm.). 11.3.4 Feeding routine If other milk formulas are not available, a formula can be made up using half strength cream powdered milk and fed with a plastic eyedropper, which the animals may lap at (Austin 1997). Milk should be fed at approximately 36°C. Older animals (if furred) will generally lap readily from a saucer.

450

I. obesulus 400

I. macrourua P. gunnii

350

P. nasuta

Weight (g)

300 250 200 150 100 50 0 0

10

20

30

40

50

60

70

80

90

100

Age (days)

Figure 2. Growth in body weight of several species of bandicoots. From Mackerras and Smith (1960), Lyne (1964), Gemmell et al. (1984a); Austin (1997).

Bandicoots

The bandicoot is given 10% of its body weight in ml per day. The number of daily feeds changes as the joey develops (Bellamy 1992). Very young, unfurred joeys should be fed every two to three hours around the clock (ie, eight to 12 feeds per day). When furred, the number of feeds is reduced to five and the volume increased per feed. At full emergence, the number of feeds is reduced to two or three a day. Once fine fur begins to emerge, Farex or Heinz Rice Cereal can be added to the formula and invertebrates such as earthworms, mealworms, grubs, moths snails and grasshoppers can be offered, mixed in with Wombaroo Small Carnivore or Insectivore Mix (Austin 1997). Milk can be offered from a small dish from 50 days of age as bandicoots quickly learn to feed themselves. If the young develops diarrhoea, the milk formula should be replaced with Vytrate, an electrolyte solution, until the faeces are firm (Kingston 1998). Vytrate can be used at a ratio of 20 ml Vytrate to 250 ml water (J. Cowey pers. comm.). Once firm faeces have been established, the milk formula can be reintroduced by providing 75% water and 25% milk for 24 hours, increasing to 100% milk over the following three days. When feeding, it is important not to feed the milk formula too quickly. The rate at which the milk is squeezed into the mouth should not be faster than the rate at which it is swallowed. Ensuring the hole in the teat is no larger than a pinhole will help. Too much milk results in an accumulation in the pharynx, which is suddenly sneezed or coughed out the nostrils. To avoid this, be very careful of the rate at which milk is released to the joey and use a smaller hole on the teat if required.

11.4 Specific requirements When first brought in for hand-rearing, the animal may be dehydrated. If so, give it plain boiled water, with 5 g (one teaspoon) of glucose to 100 ml of water or 1 g of electrolyte replacer if available (Austin 1997). It is important to warm the joey prior to feeding to avoid the risk of inhalation pneumonia. If this is taking too long, give fluids subcutaneously and bottle-feed later. If the joey is really cold, place it in a warm water bath and dry it off rather than putting it in a hot box (J. Cowey pers. comm.).The skin of unfurred and slightly furred young should be kept moist with the use of Sorbelene cream (not with added glycerine) so that the skin does not become dry and cracked (George et al. 1995). Baby oil does not appear to be properly absorbed, it tends to stay on the skin surface where it rubs off and is absorbed by the liner bag fabric (George et al. 1995).

Stress is a major problem in rearing native mammals successfully and can be fatal. It is important to minimize noise, not to overhandle animals and to maintain high standards of hygiene (A. Gifford pers. comm.).

11.5 Data recording When an animal is first brought in for hand-rearing, its sex and approximate age, using growth charts, should be recorded. During the hand-rearing process a number of important pieces of information should be recorded. This information serves several purposes, including providing important background information such as food consumption data which will assist a veterinarian reach a diagnosis if the animal becomes sick or fails to grow or gain weight. It also allows a comparison with growth curves to assess progress (see Section 10.16) and enables growth curves to be established for measurements where they do not already exist. The following information should be recorded on a daily basis: ■ ■ ■ ■ ■

■ ■ ■



11.6 Identification methods If large enough the ears can be tattooed. Once furred, PIT tags can be used (see Section 5.3.1).

11.7 Hygiene and special precautions Maintaining a high standard of hygiene is critical to the survival of the bandicoot joey. Emphasis needs to be placed on the following: ■

■

Maintain a clean pouch lining at all times, older joeys can be trained to urinate on newspaper by keeping a piece of newspaper with the smell of urine on it. Maintain personal hygiene by washing and disinfecting hands before and after handling the joey. Use antibacterial solution for washing hands with furless joeys, as their immune system is not well developed.

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144


■ ■

■

■

■

■ ■

■

■

■

Wash hands between feeding different joeys. Use boiled water when making up formulas for very young joeys. Spilt milk formula, faeces and urine should be cleaned from the joey’s skin and fur as soon as possible, and then the animal should be dried. All feeding equipment should be washed in warm soapy water and sterilized in a suitable antibacterial solution such as Halasept or Milton, or boiled for 10 minutes. Once sterilized the equipment should be rinsed in cold water. Many carers store teats and bottles in the fridge after they have been disinfected (J. Cowey pers. comm.). Only heat up milk once and discard leftovers. Contact with other animals should be avoided unless you are sure they pose no health risk. Stimulate to toilet before or after feeding. As with other marsupials, toileting can be done by the application of warm water to the cloaca using cotton wool to stimulate urination and defecation, which allows the animal to keep drier and warmer in its pouch. If furless, cover the joey’s body with Sorbelene cream after each feed until fur appears. Use a new pouch liner after each feed.

11.8 Behavioural considerations There are no specific considerations as they do not appear to show any bonding, although if they are to be released they should not be exposed to other species of animals, with which they may become accustomed. It appears that they may do better if paired with another bandicoot of approximately the same age (J. Cowey pers. comm.).

11.9 Use of foster species Although the use of cross fostering does not appear to have been actively pursued, bandicoots appear to be suitable for this technique. Three young northern brown bandicoots were found to move through a wire fence from their mother’s enclosure into an adjacent enclosure and into the pouch and onto the teat of a female that had

two young (Gemmell 1988a). The young appeared to move between day 44 and 50 after birth and were successfully weaned (Gemmell 1988a). Despite these observations cross fostering should not be relied upon as bandicoots lose or eat their young when disturbed (R. Gemmell pers. comm.).

11.10 Weaning Solid food can first be offered in eastern-barred bandicoots at approximately 60 days of age. Initially, pureed boiled eggs and cat food are readily accepted (Kingston 1998). Once the bandicoot is lapping water readily, the amount of solid food is slowly increased over the next two to three weeks. It can include diced apple, sweet potato, corn, kiwi fruit, tomato and crushed Eukanuba® Kibble (Kingston 1998). Finely diced lean meat mixed with Wombaroo insectivore powder can also be used (L. Baume pers. comm.). Live food such as earthworms, fly pupae, mealworms, moths and other invertebrates should also be provided. Most species of bandicoots should be weaned by four to five months of age (Austin 1997). At weaning, fresh water should be supplied.

11.11 Rehabilitation and release procedures Prior to release, they should be placed in an outside enclosure, which is as large as possible and given as much live food as possible, including earthworms, fly pupae, beetles and moths, to encourage foraging behaviour. Single animals, reared properly, do not imprint on their rearer (L. Baume pers. comm.). Males can be particularly aggressive when defending their ‘captive’ territory. This is important for them in the wild to claim wild territories (L. Baume pers. comm.).

12. Acknowledgments Sincere thanks to John Seebeck and Dr Robert Gemmell for the many valuable comments they made throughout this manuscript that greatly assisted in its development.

Stephen Jackson, Katie Reid,

6 KOALAS

Des Spittal and Liz Romer Photo by Stephen Jackson

1. Introduction The koala Phascolarctos cinereus and the large kangaroos are probably Australia’s most popular mammals. The empathy created by the koala appears to be because it is one of the few mammals that have a face rather than a muzzle, a trait it shares with humans (Lee and Martin 1988). The koala is nocturnal to crepuscular and is one of the largest arboreal mammals (4.1–14.9 kg), resting in trees without building nests (Martin and Handasyde 1995). The koala’s feet and hands are well developed with long, sharp claws, which help it climb branches and tree trunks. The fur is thick, short, fine and dense, with some of the best insulating properties found in marsupials, verging on those of some arctic mammals (Cronin 1987). Its colour varies between locations, ranging from light to dark grey on the back and sometimes showing touches of brown and white or yellowish fur on the underbelly. Initially, koalas did quite poorly in captivity, most of them dying after only a very short period. In 1803 (at which time it was known the Aborigines called it a Koolah) a soldier kept a female with ‘two’ young, that lived for over a month on gum leaves and bread soaked in milk or water (Stanbury and Phipps 1980). London Zoo maintained its first koala, which it received in 1880, by feeding it dried eucalypt leaves brought from Australia and later fresh leaves (Flower 1880). Subsequent koalas often lived for less than a year after being offered food items that included bread, milk and honey, and eucalyptus throat pastilles (Crandall 1964). Koalas were first held by the New York Zoo in 1920 but died only five days later after refusing both dried and refrigerated leaves (Crandall 1964). San Diego received two koalas in 1925 of which one died after five months, while the other survived nearly two years using the local introduced populations of eucalypts (Crandall 1964). San Diego received another four specimens in 1952 that lived five to six years and were fed from the abundant eucalypts present in the area (Crandall 1964). Further koalas received by San Diego Zoo and San Francisco Zoo produced young in 1960 (Pournelle 1961). Koalas were sent from Taronga Zoo to Tama Zoo and Nagoya Higashimyama Zoo and from Lone Pine Koala Sanctuary to Kagashima Zoo in Japan in 1984 (Jackson 2001). In Australia the first records of koalas in captivity are from Taronga Zoo in Sydney, which began keeping koalas in 1914, two years before it officially opened. Lone Pine Koala Sanctuary in Brisbane received koalas from Taronga Zoo in 1932 (Jackson 2001). The first breeding in captivity was at Melbourne Zoo and the Koala Farm at Adelaide in 1937 and in 1938 at Taronga Zoo in Sydney (Fleay 1937; Minchin 1937; Crandall 1964). Today koalas are held in numerous zoos throughout Australia, the United States of America, Japan, Germany, Portugal, Belgium, Taiwan, South Africa (Jackson 2001; Lees and Johnson 2002). Taronga Zoo loaned several individuals to the Singapore Zoological Gardens for six months in 1991, and food had to be packed and flown to Singapore daily to ensure that the specialized dietary

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needs of the animals would be met (Jackson 2001). More recently, various European, African, and Southeast Asian zoos have also expressed interest in acquiring koalas for their collections (Jackson 2001). Due to their popularity, koalas are a good educational tool for increasing public awareness of conservation for both children and adults (Finnie 1990). Koalas in zoos can be ambassadors for conservation, particularly as the major factors affecting the long-term survival of wild koalas, and many other species, is the availability of suitable habitat.

Koalas

2. Taxonomy 2.1 Nomenclature The koala was first described by Goldfuss in 1817 as Lipurus cinereus. The present genus name Phascolarctos was described by Blainville in 1816. The koala is the only member of the family Phascolarctidae. Class: Mammalia Supercohort: Marsupialia Cohort: Australidelphia Order: Diprotodontia Suborder: Vombatiformes Family: Phascolarctidae Genus Species: Phascolarctos cinereus Etymology Phascolarctos – pouched bear cinereus – ash-coloured

2.2 Subspecies Koalas have been regarded as having three subspecies. The nominate subspecies P. c. cinereus has a range extending along the east of New South Wales (type specimen from unknown location in New South Wales). The northern subspecies P. c. adustus (Thomas 1923) is found in Queensland, with the type specimen coming from O’Bil Bil near Mundubbera. The third subspecies P. c. victor (Troughton 1935) is found in Victoria with the type locality being Booral (Martin and Handasyde 1995). Confusion exists over the relationship between the three subspecies. Their ranges are presently defined by state borders, but variation may be due to a cline or continuum. The described subspecies were named by scientists with access to only a few specimens and with no idea of the extent of individual variation in any one area (Cronin 1987). It has also been suggested that koalas do not cling to state boundaries, and it is clear that having these subspecies creates artificial boundaries in a north–south trend or cline (Lee and Martin 1988). More recent genetic research by Houlden et al. (1999) found limited genetic distinction between geographically distant populations, suggesting a tentative support for koalas to be considered a single evolutionary significant unit. As a result, all populations should be referred to under the scientific name of Phascolarctos cinereus with no recognized subspecies (Lee and Martin 1988), however two captive management units have been developed, a northern and southern, which reflect the clinal variation in koalas.

Table 1. Average body weight and size for koalas in Queensland and Victoria. Location

Weight (range)(kg)

Head Body Length (range)(mm)

Males

6.5 (4.2–9.1)

705 (674–736)

Females

5.1 (4.1–7.3)

687 (648–723)

Males

12.0 (9.5–14.9)

782 (750–820)

Females

8.5 (7.0–11.0)

716 (680–730)

Queensland

Victoria

From Martin and Handasyde (1995)

The closest extant relatives of the koala are the wombats, which share the same Suborder Vombatiformes.

2.3 Recent synonyms Synonyms of koalas can be found in McKay (1988).

2.4 Other common names Koala bear or native bear – despite these names they are not at all related to bears.

3. Natural history 3.1 Morphometrics Adult koalas can weigh between 4.1 and 14.9 kilos and reach 648–820 mm in body length depending on sex and latitude (Table 1) (Martin and Handasyde 1995). Sexual size difference is evident, with males being about 50% larger than females (Lee and Martin 1988). It is suggested that this sexual dimorphism is associated with the polygynous mating system and a male dominance hierarchy (Tyndale-Biscoe and Renfree 1987). The koala has small eyes in comparison to the size of the head, with the slits of the pupils being vertical rather than horizontal as in other marsupials. Its fur is thick and woolly and thicker and longer on the back than on the belly. Both the inside and outside of the ears are heavily furred (Lee and Martin 1988). Koalas have a shorter coat the further north within their distribution they progress, due to the increase in average temperatures. The colour and pattern of the coat varies considerably between individuals and with age (Lee and Martin 1988). The male Victorian koala is 70% and the female 90% larger than their Queensland counterparts (Cronin 1987). The Victorian race also has a heavier, shaggier coat with more fur in the ears and around the face while the Queensland koala is somewhat smaller in size and sleeker in coat.

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a

b Figure 1. Profiles of the head of male and female koalas (a) a male koala, (b) a female koala, illustrating the distinctive ‘Roman’ nose of the male and the straighter nose of the female.

The koala has a number of features, some of which it shares with the wombats, which distinguish it from the other diprotodont marsupials. In contrast to the wombats, the koala has three incisors on either side of the upper jaw and the teeth have roots. The manus (hand) is forcipate with digits I and II opposed to the remaining three digits, each one terminating in a strongly curved claw (Lee and Carrick 1989). The females have a pouch which contains two teats and opens centrally and downwards when not occupied, and backwards when there is a large pouch young present. Males have a prominent sternal gland, which normally stains the fur around this area orange to dark brown. Male koalas can be distinguished from females by the shape of the head (Fig. 1). The head of adult males is larger than that of females, and appears broader and squared off in profile. Males also have a broad rather than pointed chin, relatively small ears and a large pendulous scrotum.

3.2 Distribution and habitat The koala is found on the east coast of Australia from Queensland to Victoria (Fig. 2). Scattered populations can be found from the extreme east coast of Victoria to the extreme west. In the 1870s and 1880s, koalas were released on Phillip Island in Westernport Bay and on

Figure 2. Present day distribution of the koala. Taken from Martin and Handasyde (1999) with permission of UNSW Press.

French Island, and later on other islands (Cronin 1987). The vast majority of the NSW koalas occur east of the Great Dividing Range from Sydney to the Queensland border, with further populations scattered in an arc from Sydney to Dubbo. The south-east corner of Queensland is the stronghold of the Queensland race. Scattered populations occur all along the coast up to Townsville and sections of the Atherton Tableland with a small population at Ravenshoe being the most northerly location recorded to date (Cronin 1987). Throughout its distribution, koalas are found in various habitats that range from open forests to woodlands and from the tropics to cool-temperate regions. Within its range it is limited to areas where there are acceptable food trees.

3.3 Conservation status Despite its large decrease in distribution, the koala is considered to be at low risk of extinction, though near threatened. The NSW population is not doing as well as those of Queensland and Victoria and is classified as vulnerable. In recent years, continued clearing of large tracts of eucalypt forest has restricted the population to small patches of discontinuous and possibly sub optimal habitat. It appears that the survival of many populations will depend on appropriate forestry management. In residential areas protection from roads is required in order to minimize the numbers injured or killed by vehicles.

Koalas

3.4 Diet in the wild Koalas feed predominantly on the foliage of eucalypts (including the genus Corymbia), with some non-eucalypts also contributing to the diet (Table 3). Although there are many species that koalas typically eat, they frequently feed on some trees and not others of the same species, and although it has been suggested, there is presently no evidence that soil type has any influence on palatability (W. Foley pers. comm.). Intraspecific variation in palatability of eucalypts for koalas is controlled by the variable concentrations of formylated phloroglucinol compounds (FPCs). However, FPCs do not occur in the Monocalyptus sub genus (that includes stringy barks and peppermints) and so if there is intraspecific variability in these species it is controlled by something unknown. There are no data that demonstrate a reliable variation in palatability within any Monocalyptus (W. Foley pers. comm.). Koalas are occasionally found sitting in, and even feeding on, trees of genera other than Eucalyptus (and Corymbia) including Melaleuca, Lophostemon, Banksia, Acacia, Hakea, Pinus, Leptospermum, Allocasuarina and Callitris (Hindell and Lee 1987; Moore and Foley 2000; Phillips and Callaghan 2000; Gifford pers. comm.). There is also a record of a koala eating bracken Pteridium esculentum (G. Underwood pers. comm.). Throughout its distribution, the koala exhibits marked local and seasonal preferences in its diet (Lee and Martin 1988; Martin and Handasyde 1999). See Moore and Foley (2000) for an excellent review of feeding and diet selection in koalas. As eucalypt leaves have a high water content (approximately 60–80%), koalas normally don’t need to drink, but obtain sufficient water from their food. Eucalypt leaves have a high fibre and low protein content. They contain strong-smelling oils, phenolic compounds and sometimes cyanide precursors that make them unpalatable or even poisonous to most mammals. To cope with this diet, the koala has numerous adaptations including their teeth that finely cut down the leaves, an enlarged caecum, a capacity to detoxify the toxic compounds in their food and a low metabolism. Oils and phenolic compounds are detoxified in the liver and leaves containing cyanide precursors are probably avoided. There is no evidence for the widespread belief that eucalyptus oils intoxicate koalas, rendering them lethargic. The koala is delicately balanced between the minimum size enabling its liver to cope with a nutritionally poor diet of leaves and the maximum size it can attain and still have enough mobility in trees to

actually gather the leaves, hence their slow movements (Lee and Martin 1988). Although koalas obtain 90% of their digestible energy requirements from cell contents rather than fermentation (W. Foley pers. comm.), the hindgut is very well developed in the caecum and in the proximal colon. The caecum is used as a fermentation chamber and with the aid of bacteria breaks down the cellulose. Apart from the enormous size of the hindgut, the koala’s stomach also contains a cardio-gastric gland, similar to the wombat, although in the koala it is branched and more complex (Hume 1982). At the start of weaning, the joey eats semi-liquid faeces (ie caecotrophs) from the rectum of the mother (Minchin 1937). This substance is called pap and contains viable bacteria, probably from the mother’s caecum (Osawa et al. 1993). Apart from its nutritional value, this is believed to facilitate inoculation of the alimentary tract of the young animal with symbiotic bacteria enabling it to digest eucalyptus leaves (Lee and Martin 1988; Osawa et al. 1993).

3.5 Longevity 3.5.1 Wild There are few records of longevity in the wild, although an average age appears to be approximately 12 years. A female tagged on French Island was still breeding at ten years of age and a male at Walkerville, Victoria was estimated to have died at 16 years of age (Lee and Martin 1988). There are also records of females living 17–18 years (Martin and Handasyde 1995). In the past, the major causes of mortality appear to have been predation by Aborigines and dingoes and hunting by Europeans for their pelts. Other known natural predators include goannas and the powerful owl (Ninox strenua), which takes young weighing less than one kilogram. Bushfires and droughts may also kill koalas. They have no means of escaping fires that sweep through the crowns of eucalypts, and the few that survive these fires have little hope of avoiding starvation before the trees produce epicormic growth. In the early 1980s, a severe drought in central Queensland, which caused browning and loss of leaves from eucalypts, resulted in substantial mortality among koalas (Gordon et al. 1988). Other factors that influence longevity include disease, particularly that caused by the bacterium Chlamydia, and the rate of wear of the teeth, which ultimately results in an inability to masticate sufficient food to meet the animal’s nutritional needs.

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Figure 3. Classes of tooth wear on the right upper right premolar (P4) of Koalas. Taken from Martin and Handasyde (1999) with permission of UNSW Press.

3.5.2 Captivity The average longevity in captivity is around 12–14 years for females and 10–12 years for males, although a female in San Diego Zoo lived to 18 years and a female at Lone Pine is still alive at 21 years of age. The oldest male at Lone Pine was 13 years of age. In captivity the major causes of death are generally diseases (such as Chlamydia) and tooth wear (Lee and Martin 1988). 3.5.3. Techniques to determine the age of adults Martin (1981) determined the relative age of koalas using the fourth upper premolar, which was later correlated with age (Fig. 3; Martin and Handasyde 1999). Gordon (1991) developed another method for determining the approximate age of koalas. This technique provides a useful indication of the relative age of koalas, although there is high variation in the rate of tooth wear between individuals, which increases as age increases. As tooth wear is heaviest on the anterior cheek teeth and because of its accessibility, the upper premolar (P4) and molars (especially M1) are selected to determine the tooth wear class and approximate age. The tooth wear classes are shown in Figure 4 and described in Table 2.

4. Housing requirements 4.1 Exhibit design Koala enclosures should follow a number of general principles in order to satisfy minimum conditions for the keeping of animals in captivity. Further details of the Table 2. Tooth wear stages and criteria used in age assessment of koalas (Gordon 1991). The letters in parentheses correspond to the same letters in Figure 4. Tooth Wear Class

Mean Age (Years)

Age Range (Years)

Tooth Wear Stage

1

1.2

1–2

No dentine exposed on P4 (a)

2

2.0

1–4

P4 spots of wear (b)

3

2.7

2–4

P4 one line of wear (c)

4

4.3

3–6

P4 two lines of wear (d)

5

5.5

3–8

P4 circle of wear (e)

6

7.3

5–10

P4 flat, M1 not flat (f-h)

7

9.0

9

M1 flat, M2 not flat (g-i)

Koalas

■

■

Figure 4. Classes of tooth wear on the upper premolar (P4) and molars (M1-2) from the upper jaw of koalas. Taken from Gordon (1991) with permission of the publisher.

standards for exhibiting koalas in New South Wales can be found in Anon (1997) and for Queensland in Anon (1994). Conditions include: ■

■

■

Enclosures shall be constructed of such materials and maintained to ensure all animals are at all times held securely and safely. Enclosures can be open, semi-enclosed or totally enclosed design. Sufficient shelter must be provided to allow protection from wind, rain, and extremes in temperature and allow sufficient access to shade during the hot periods of the day.

The size and shape of enclosures shall provide freedom of movement both vertically and horizontally. The enclosures shall be well drained and have either a readily cleanable substrate or be of a material which can be replaced to avoid the accumulation of faeces and urine.

Institutions have used a variety of enclosure designs to display koalas. These start with a comparatively simple design with a circular or oval wall at least 1.2 m high, with a floor that is grassed or made of concrete. Rough-barked tree (eg E. obliqua) supports should be taller than 3 m with at least two natural forks (per animal) for the koalas to sit in and spaced about 3 m apart, which encourages the koalas to jump from tree to tree. The trees can be joined by lateral branches to allow them to move from tree to tree without coming to the ground. At Healesville Sanctuary (Fig. 5), the display area is approximately 50 × 50 m and is a large planted exhibit. The koalas are viewed from a large raised wooden walkway, 2 m off the ground to bring the viewer closer to the canopy. A small gallery at the centre point of the walkway contains an interpretive display and serves as a shelter area for the public during adverse weather. A 1.5 m sheet metal fence surrounds the display and branches of trees are trimmed from near the fence to prevent the animals escaping. The display is furnished with large, branching, stringybark perches, each at least six metres high. These are inserted into the ground by trimming the base to fit into terracotta pipes buried in the soil. These perches are replaced approximately every 12 months as they lose their bark and become slippery. The exhibit has 11 perches, each with soil moulded slightly around it to aid in drainage. The rest of the exhibit is grassed and planted with a variety of unpalatable trees and shrubs. The exhibit is watered with a permanent ground sprinkler system set on a timer. Water is also sprayed from a removable bayonet system elevated off the ground on 2 m poles to help keep the foliage fresh on hot windy days. The design of the koala exhibit used at Taronga Zoo is a complex helical structure with the public pathway following a loop around the koalas and spiralling up to the canopy of the trees (Fig. 6).

4.2 Holding area design Holding areas for koalas can be a simple design. They are totally roofed and can be constructed of chain or welded mesh of a size to ensure that koalas are not able to get any

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Figure 5. Design of koala display at Healesville Sanctuary. Taken from Drake et al. (1991). Although electric fencing has been used successfully it is known to have caused several deaths (G. Underwood pers. comm.) and is therefore not recommended.

part of their body stuck. An area of at least 2 × 2 × 2 m with two or three forks and cross branches is adequate for one or two koalas. A cement floor, well drained to a good sized sump with a grate is the easiest way to maintain off-exhibit koalas on a long-term basis, as there is not the need to replace dolerite substrates regularly. The floor is swept, hosed and scrubbed daily to remove any algal growth and ensure it is safe and hygienic.

4.5 Weather protection The trees in the exhibit can be placed in a compact arrangement to help insulate the animals against the cold (Drake 1982). Alternatively, enclosure walls can be placed on the side from which the prevailing weather comes from.

4.6 Temperature requirements

Areas of enclosures typically range from 30–100 m2 for two to four animals (see Sections 4.1 and 4.2 for more details). An additional area of 2.5 × 2.5 m should be provided for each extra animal.

No heating is generally required for koalas unless they are held at temperatures that are constantly low (0°C or less), where they may need to be held indoors with a source of heating, although they have been observed to tolerate very low temperatures (as low –10°C) for many weeks (G. Underwood pers. comm.; pers. obs.).

4.4 Position of enclosures

4.7 Substrate

The position of an exhibit is important, particularly in regard to aspect, because the koalas need shelter from wind, rain and extreme heat and also to have the opportunity of warming themselves during cold weather. Shelter can be provided in the form of partial or total overhead coverage by arranging the trees in a compact pattern.

The base of the enclosure can be made of any number of materials, from concrete to various types of soil, leaf litter or dolerite. Dolerite is especially good under perches, as it is easily raked and drains well, leaving a dry, compacted and attractive surface. In display exhibits it is better to use soil as it is more aesthetically pleasing while off-exhibit holding enclosures are easily maintained with smooth


Koalas

Figure 6. Design of the koala display at Taronga Zoo. The cross hatching in the plan view represents the exhibit area.

finished concrete. The base of the enclosure must drain readily to ensure that in the event of rain the koalas are able to move between trees without having to wade through water.

4.8 Enclosure furnishings In an exhibit, two trunks with two or three forks each should be supplied for each koala. The forks should be no less than 1.8 m from the ground and not closer than 0.9 m to the next fork. These should not be close enough to the edge of the enclosure to allow escape. All supports and branches should provide sufficient traction for koalas to climb easily and safely. At least one leaf pot should be provided for each individual as this will allow plenty of room to move and reduce the incidence of aggressive encounters, particularly during the breeding season. Each trunk should be very sturdy and ideally have a base diameter of 10–15 cm, and have rough bark (eg ironbark species) to assist in the koalas’ climbing mobility. Cross branches can also be supplied to link each of the tree trunks and to help the females escape from male aggressive behaviour. These may not be required if the trees are placed

reasonably close together, with limbs from adjacent trees that come within 1–2 m of each other as the koalas will be able to jump from one tree to another. If the koalas are unable to jump from tree to tree, they will readily come to the ground to move from one to another. Using only vertical branches with intact side branches is advisable for display animals, as it looks more naturalistic than branches tied horizontally between vertical trunks. Ideally, a garden and other trees should also surround the exhibit to provide additional shade from the sun, shelter from the wind and rain, and to help prevent the enclosure from looking like a round pit. Shade trees should be watered regularly and may need the protection of metal guards to prevent the koalas climbing them. Although the metal guards can be painted brown so they are more aesthetically pleasing, they can still look unsightly. As the tree grows, the metal will need to be checked so that the tree doesn’t grow over it and cause it to buckle. Depending on the size and position of the shade trees it may be appropriate to let the koalas climb in them, particularly as this may bring them voluntarily closer to the public. But take care that the trees surrounding the exhibit do not allow the animals to escape. They will make use of any overhanging limbs, and even fern fronds, if given the opportunity. As a general rule, a 1.8 m gap should stop any koalas from escaping. Generally, koala branches are long lasting, however they will need to be replaced when the surfaces of the trunk begin to wear smooth, which is usually every 12 months. Depending on the size and accessibility of the trunks and exhibit a crane may be required to lift out and then place new trunks, which may be 6+ metres high, and 40–60+ cm in diameter.

5. General husbandry 5.1 Hygiene and cleaning All enclosures should be cleaned daily to remove faecal matter and uneaten food. Soil substrates should be raked and concrete substrates hosed daily to remove all faecal matter. If the koalas are held in large enough grassed enclosures at low densities then raking may not be required (G. Underwood pers. comm.). All faecal material should be removed from the tree trunks as necessary. All feed pots should be emptied and refilled daily to keep the water fresh. Drinking water dishes should be cleaned and refilled daily. When a koala permanently leaves an enclosure with a concrete floor, the floor should be thoroughly disinfected and scrubbed in preparation for the next arrival.

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5.2 Record keeping It is important to establish a system whereby the health, condition and reproductive status of captive koalas are routinely monitored. Records should be kept of: ■

■ ■ ■ ■ ■ ■ ■

■ ■

Identification numbers, all individuals should be identifiable Any veterinary examination conducted Treatments provided Behavioural changes or problems Reproductive behaviour or condition Weights and measurements Changes in diet Movements of individuals between enclosures or institutions Births with dam and sire if known Deaths with post mortem results.

The collection of information on physical and behavioural patterns of each individual can contribute greatly to the husbandry of these species. It also allows the history of each individual to be transferred to other institutions if required and greatly facilitates a cooperative approach to data collection amongst institutions. In most of the larger institutions ARKS (for general information on births, transfers and deaths), SPARKS (breeding studbook for species) and MedARKS (veterinary information) are used. These systems have been developed by the International Species Information System (ISIS), which is part of the Conservation Breeding Specialist Group (CBSG) software. As these are standardized, there is a high degree of efficiency in transferring information between institutions. When new establishments seek to exhibit koalas they may be required to maintain additional records on diet to provide an index of appetite and feed preference. This precaution may be necessary because of local and seasonal differences in digestibility and palatability of leaves. Because of the changes to the palatability of leaves, new exhibitors may be required to demonstrate access to adequate fresh supplies of leaves from at least three species of koala food trees in their local region that are considered most favoured.

5.3 Methods of identification Each animal should be individually identified and have its own record card. There are several methods used to identify koalas for maintaining records. 5.3.1 Passive Integrated Transponder (PIT) tags These are implanted between the scapulae of individuals and can be used on all koalas. This is an excellent method

of identification, however it can be expensive if many animals are implanted. PIT tags are a permanent method of identification but take care when they are implanted as they may track out along the injection site. This may be avoided by sealing the entry wound with tissue glue (Vetbond®) or similar fast setting adhesive. They generally require the animal to be caught to confirm identification with a PIT tag reader. Further details can be found in Vogelnest (1998). 5.3.2 Tattoos Tattoos work well on koalas and are best placed below the centre of the ear as the edge of the ear becomes pigmented with age. 5.3.3 Visual identification Generally, koalas have quite distinctive faces, which can be readily distinguished from each other with practice. Potentially, a photo could be taken of their faces and kept for record. Nonetheless, a form of permanent marking is still recommended. 5.3.4 Ear tags These are probably the most used form of identification in koalas. Large coloured ear tags such as Sheep Tags (Leader Product) are generally effective in determining individuals without catching them, although these are often hidden by the fur on the ears particularly in the Victorian koalas (this can be overcome by trimming the ear fur). Care is needed to avoid veins when making the hole through the ear.

6. Feeding requirements 6.1 Captive diet Ad Lib Water Branches of eucalypt leaves (usually two large or three smaller branches of different species are provided daily), though branches still containing fresh leaves should always be available. 6.1.1 Species of eucalypts preferred To ensure that the koalas held by an institution are kept in good physical condition, the diet must be varied and of high quality. A koala typically eats between 400 and 1000 g (approximately 10% of its body weight) of eucalypt foliage per day (Hawkes 1978; Nagy and Martin 1985). Koalas show a definite preference toward some eucalypt species with some being highly preferred, others eaten occasionally, and others rarely, if ever, eaten. Of

Koalas

Table 3. Species of eucalypts eaten by koalas throughout their distribution. Scientific name

Common name

Qld

NSW

E. acaciiformis

Wattle-leaved Peppermint

–

*

Vic –

E. acmenoides

White Mahogany

–

*

–

E. agglomerata

Blue-leaved Stringybark

–

*

–

E. amplifolia

Cabbage Gum

–

*

– ***

E. botryoides

Southern Mahogany

–

*

E. bridgesiana

Apple Box

–

*

*

E. camaldulensis

River Red Gum

***

***

***

E. camphora

Mountain Swamp Gum

–

*

*

E. canaliculata

Large-fruited Grey Gum

–

*

–

E. cephalocarpa

Silver-leaved Stringybark

–

–

*

E. citriodora

Lemon-scented Gum

–

*

–

E. coolabah

Coolabah Tree

*

–

–

E. creba

Narrow-leaved Red Ironbark

*

*

–

E. cypellocarpa

Mountain Grey Gum

–

*

*

E. drepanophylla

Grey Ironbark

*

–

–

E. dunnii

Dunn’s White Gum

*

–

–

E. exserta

Queensland Peppermint

*

–

–

E. eximia (Corymbia)

Yellow Bloodwood

–

*

–

E. eugenoides

Thin-leaved Stringybark

–

*

–

E. fastigata

Brown Barrel

–

*

– ***

E. globulus

Tasmanian Blue Gum

–

***

E. globoidea

White Stringybark

–

*

–

E. goniocalyx

Long-leaved Box

–

***

***

E. grandis

Flooded Gum

*

*

*

E. gummifera (Corymbia)

Red Bloodwood

–

*

–

E. haemostoma

Scribbly Gum

–

*

–

E. henryi

Large-leaved Spotted Gum

*

–

– ***

E. leucoxylon

Pink Flowering Gum

–

–

E. macrorhyncha

Red Stringybark

–

–

*

E. maculata (Corymbia)

Spotted Gum

*

*

–

E. maidenii

Maiden’s Gum

–

*

–

E. major

Brittle or Red Spotted Gum

*

–

– –

E. mannifera

Mottled Gum

–

*

E. melliodora

Yellow Box

*

–

*

E. microcorys

Tallowwood

***

***

–

E. moluccana

Grey Box

*

*

–

E. nicholii

Narrow-leaved Peppermint

*

*

*

E. obliqua

Messmate

–

***

***

E. oblonga

Narrow-leaved Stringybark

–

*

–

E. ochrophloia

Yapunyah

*

–

–

E. orgadophila

Mountain Coolibah

*

–

–

E. ovata

Swamp Gum

–

***

***

E. paniculata

Grey Ironbark

–

*

–

E. parramattensis

Parramatta or Drooping Red Gum

–

*

–

E. pellita

Large-fruited Red Mahogany

*

–

–

E. pilularis

Blackbutt

*

***

–

E. piperita

Sydney Peppermint

–

*

–

E. polyanthemos

Silver Dollar Gum or Red Box

–

–

*

E. populnea

Poplar Box or Bimble Box

*

–

–

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Table 3. Species of eucalypts eaten by koalas throughout their distribution. (Continued) Scientific name

Common name

Qld

NSW

E. propinqua

Small-fruited Grey Gum

***

***

Vic –

E. punctata

Large-fruited Grey Gum

***

***

***

E. racemosa

Southern Scribbly Gum

–

*

–

E. radiata

Narrow-leaved Peppermint

–

***

***

E. regnans

Mountain Ash

–

–

*

E. resinifera

Red Mahogany

*

*

–

E. robusta

Swamp Mahogany

*

*

*

E. rossii

Scribbly Gum

–

*

– *

E. rubida

Candle Bark, Ribbon or White Gum

–

–

E. saligna

Sydney Blue Gum

*

*

*

E. scoparia

Wallangarra White Gum

–

*

–

E. seeana

Narrow-leaved Grey Gum

*

–

–

E. sideroxylon

Red Ironbark

*

*

–

E. signata

Scribbly Gum

*

–

–

E. tereticornis

Forest Red Gum

***

***

***

E. tessellaris (Corymbia)

Moreton Bay Ash

*

–

–

E. umbra

Broad-leaved White Mahogany

*

–

–

E. viminalis

Manna Gum

***

***

***

L. conferta

Brush Box

*

–

–

From Taronga Zoo, Lone Pine Sanctuary, Currumbin Sanctuary, Melbourne Zoo, Healesville Sanctuary, Tidbinbilla Nature Reserve, Martin and Handasyde (1999) and Phillips and Callaghan (2000) Most preferred species are marked with a triple asterix

more than 800 species of gum trees (which now include three genera Eucalyptus, Corymbia and Angophera), koalas have been recorded eating approximately 70 species at some time (Table 3). Each koala’s choice varies according to locality and season. In captivity only a few species of eucalypts are suitable as staple foods. The staple browse species include Eucalyptus tereticornis, E. camaldulensis, E. microcorys, (coastal New South Wales and Queensland), E. punctata (central coastal New South Wales) and E. viminalis and E. globulus (Victoria and South Australia) (Hawkes 1978). Taronga Zoo generally feeds three species which form the basis of the food supply; E. punctata, E. tereticornis, E. camaldulensis, and a variety of others to provide seasonal variations eg E. viminalis, E. microcorys, E. obliqua. At Melbourne Zoo the koalas are regularly fed foliage from the following six species of eucalypts, listed in order of preference: E. viminalis, E. ovata, E. goniocalyx, E. radiata, E. obliqua and E. botryoides. E. camaldulensis foliage is also provided when available and is readily accepted (Drake et al. 1991). 6.1.2 Choice of eucalypt branches to be cut Part of the skill of successfully maintaining koalas involves knowing which species of gum is the most appropriate to feed at different times of the year as the

preference within and between species varies considerably throughout the year. There are a number of components of eucalypts that potentially play a role in palatability (including fibre, oils and some types of phenols) but the only aspect that has ever been shown to be important is the content of FPCs in Symphyomyrtus. Winter is considered the time of greatest nutritional stress on koalas as at this time there is very little, if any, new growth available, with most of the leaves being quite fibrous. It is particularly important at this time to supply as wide a choice of species as possible. Depending on the species and time of year, branches with new tips should be chosen. Some species of eucalypts are almost wholly eaten, adult leaves included, while in others, only the new growth is eaten. Note that koalas do not always prefer young tips; Pratt (1937) found koalas to reject the young leaves of juvenile trees (especially E. viminalis) while another study found young foliage accounted for 5–35% of the diet while mature foliage comprised 50–90% of the diet of four rehabilitated koalas (U Nyo Tun 1993 in Moore and Foley 2000). Cut branches are normally at least one metre long and contain as much fresh new growth as possible. The diameter of the cut branches is generally around 2–5 cm

Koalas

and they are best cut at an angle of 45° to facilitate maximum coppice regrowth. The frequency of leaf collection varies from once or twice a week to every day. A minimum of three to four species of gum are collected each trip and the gum should be kept out of direct sun and wind (particularly during summer) to prevent dehydration of the tips. 6.1.3 Storage of leaves The leaves should be stored for a maximum of one week, though ideally no more than two to three days, or until the condition of the leaves has deteriorated. They should be stored in an enclosed, shaded area with an overhead sprinkler system, where the leaves are kept wet by a fine mist of water spray, and prevented from drying out, particularly in hot dry weather as the tips can also brown very quickly, making them unpalatable. Alternatively, the branch of leaves can be kept in a refrigerated unit at 4–5°C, however refrigeration can dry the tips out so it is not always recommended (it is likely that some refrigerators are better than others). The leaves should be stored in large bins filled with water, changed at least once per week, that are approximately 60–80 cm high with a diameter of about 60 cm. Plastic pots work well as they won’t rust and are easy to clean. It is important to clean the pots weekly to remove the build-up of any algae and other rubbish in the water. Other containers such as troughs with partitioning can also be used. 6.1.4 Eucalypt plantations The maintenance of captive koalas increasingly requires the establishment of plantation grown trees as the native eucalypt stands are often inadequate or, in the case of overseas zoos, not available, particularly as koalas require a number of species. In order to establish a plantation, the size of the population to be fed and their daily requirements will need to be established. For each koala, you need to plant about 500–1000 trees (comprising at least five or six preferred species) about four to six years ahead of acquiring the animals. A brief outline is given below for the establishment of a plantation. A more detailed description can be found in Hawkes (1978), and Congreve and Betts (1978) and a more recent outline is given in Addendum 1. A number of aspects need to be considered when planning the establishment of a plantation. These include: location, tenure, accessibility, construction of capital improvements, harvesting regime and other

factors regarding the future management of the plantation. Once planted, the area should be left untouched until the young trees are about eight to ten metres high and have a closed canopy. This occurs at about four to seven years of age, depending on the species and the site. At this stage, coppicing a proportion of the stems, approximately 20% of the stand, would allow continuing growth on the crowns of the more vigorous browse trees and allow the stocking of browse trees to be manipulated. When collecting branches, it is important for the long-term management of the plantation not to overcrop or coppice individual trees. If over-cutting is occurring, more trees should be planted. Eucalypt plantations are usually established for forestry purposes with one tree per 4 m2, giving an initial stocking of 625 trees per hectare. After treatment this stocking will be reduced to 500 plants per hectare. Ingrowth from the coppiced stumps will replace those stems removed, with the effect of introducing a second age class into the plantation (Hawkes 1978). If all the coppices are removed from a stump, foliage can generally be harvested from E. viminalis and E. goniocalyx at intervals of 12 to 14 months (Drake et al. 1991). Some species, such as E. ovata, can be harvested every six to eight months because the koalas do not reject juvenile leaves and regrowth is rapid (Drake et al. 1991). 6.1.5 Artificial diets The use of an artificial diet has been tested with koalas in the form of a thin flexible biscuit and a thick paste (Pahl and Hume 1991). The moisture, nitrogen and fibre contents of the biscuits are similar to those observed in leaves preferred by koalas. Using dry weights, the biscuit cell wall content is 24%, cellulose content 16%, lignin content 3%, ash content 6%, nitrogen content 1.9% and moisture content 62%. The biscuit form of the artificial diet is 2 × 15 × 60 mm in size (Pahl and Hume 1991). The thick paste consists of ‘Presbo’ powder, a constant amount of ground Eucalyptus foliage, and water. The biscuits are always dipped into the paste by hand before they are presented to the koalas, but the paste is also administered orally with a syringe (Pahl and Hume 1991). Although koalas’ weight can be sustained for a limited period of time by the use of artificial diets combined with fresh foliage, this practice is very time consuming and the koalas appear to become less willing to eat artificial diets after an extended period of time. Therefore it is not recommended for the long-term maintenance of koalas and is not used by any institution.

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6.1.6 Supplementary milk diets for aged and sick koalas As koalas age, their teeth become increasingly worn so the cutting edge decreases and becomes less efficient in grinding food. This results in larger particles to digest and less efficient digestion, so significant increases occur in the amount of time spent feeding and the number of leaves chewed, but ultimately ill-health occurs due to malnutrition (Lanyon and Sanson 1986; Gamble and Blyde 1992; Logan and Sanson 2002). Supplementary feeding can be of great use in maintaining sick or old koalas that have unweaned young and are losing weight, as it provides additional nutrition to compensate for the increased energetic demands during lactation and alleviate the need to hand-rear a koala (Osawa and Carrick 1990). Portagen (28 g powder/ 100 ml water) or a mixture of Portagen (14 g powder/ 100 ml water) and Infasoy (14 g powder/100 ml water) offered twice per day (Gamble and Blyde 1992) has been used successfully by initially force-feeding using a syringe, although after two to three days the animals readily accept the milk substitute. Other alternative supplements include a mixture of 50/50 Prosobee/ Portagen (14 g powder/100 ml), and BioActive (14 g powder per 100 ml water). Vytrate (as a hydration fluid) has also been offered in case the koala is thirsty, although they sometimes will not readily accept it (Phillips and Johnson 1994). Vytrate can be used at a ratio of 20 mls Vytrate to 250 ml water (J. Cowey pers. comm.).

6.2 Supplements None required.

6.3 Presentation of food Always feed a surplus of food. Generally, at least three branches (though sometimes two larger branches of favourite species can be used), of at least two species, should be provided to each koala per day, in long thin pots (about 10–15 cm in diameter and 60–70 cm long) that are filled with water. However, sometimes only one species can be fed, depending on availability and preference. The provision of different species of eucalypt leaves allows the koalas to always have at least two species that they will eat. All branches should be free of foreign material such as dirt, insects and bird droppings. All browse should be fed out as fresh as possible, with no obvious signs of wilting. The branches should be positioned so that all tips are within easy access of the koalas.

Figure 7. The koala leaf pot and its attachment to the tree trunk; not drawn to scale.

The pots are connected to the tree trunk just below the tree forks so the koala can sit in the fork and feel secure while feeding. The leaf pots should be rinsed and refilled daily with water before the new leaves are added. The leaf pots should be placed in the shade to minimize desiccation of the leaves. There should be at least one leaf pot (preferably two or three) per individual, spread out amongst various branch forks in the exhibit to reduce fighting over food. The leaf pots are usually made of plastic or stainless steel. Plastic pots are lighter but they are not as good for wear and tear, particularly as the bottoms often fall out if they are dropped. The metal containers are a lot stronger but they are heavier to handle. The pots can be attached to the trunk by drilling a hole at the top of the leaf pot and attaching it to a bolt that has been screwed into the tree trunk. A second method used to attach the pots to the trunk consists of an arm with an elbow, which is connected to the tree by the use of a sleeve (Fig. 7). The pot is usually positioned with the top about 1200 mm off the ground. It should be attached near a fork so the koalas can feed comfortably. The uneaten leaves in each enclosure should be changed daily. This is best done in the afternoon to stop them from drying out during the day. This is particularly important during hot weather and as the koalas generally

Koalas

won’t eat the leaves until it is dark. Some institutions change the leaves in the morning and afternoon, in which case the morning feed is minimal due to the koalas’ general inactivity during the day. Although most koalas rarely drink, fresh drinking water should be available at all times especially for sick animals.

7. Handling and transport 7.1 Timing of capture and handling Animals should be observed daily and physically checked monthly – or more regularly in the case of sick or injured animals. The best time to capture animals for examination is in the morning when the temperature is cooler. This is particularly important during warmer weather. In exhibits with tall trees it may be more convenient to capture the animals when they are fed in the afternoon as they will often come down from the higher branches to feed. This is not recommended in hot weather as the koalas are unlikely to come down to feed in the heat anyway.

7.2 Catching bags These should made of thick cotton or good quality hessian. The opening of the bag should be wide with a diameter of approximately 45–60 cm and have a depth of about 60–90 cm.

7.3 Capture and restraint techniques Koalas can generally be coaxed down a branch with the use of a long rod or broom. The rods are usually three to four metres long with a hessian sack or rag attached to the end. The rustling of large plastic bags also works very well. The sack or rag is waved just above the head of the koala, which should begin to descend the tree. The bag is kept slightly above its head as it descends. When the koala is within reach, unconditioned animals can generally be coaxed down further by placing a hand firmly on their head and pushing them gradually down the branch and into a catching bag. Koalas can also be removed from a tree by putting the catching bag over the animal’s head (which helps to calm it) and then pushing the edge of the bag over its back toward its rump, and finally unhooking its feet (Fig. 8). An alternative to catching a koala in a catching bag is to lift it off the tree by holding its forearms firmly from behind (Fig. 9a). In this way it may be safely carried facing away, at arm’s length, or effectively restrained by pressing it to the floor or table for closer examination. An

Figure 8. Restraint of a koala using a catching bag.

alternative way of carrying a koala is to grasp the fur of the neck with one hand and the fur of the rump with the other (Fig. 9b). Another method of removing a koala from a tree is to use a noose that is slung around the neck on one side and under the arm on the other. The noose is tightened and the animal pulled from the tree, or preferably flagged down the tree. This is not the preferred method as it is very stressful for the koala and when trying to position the noose the koala may climb up the tree and out of reach. Although koalas appear to be docile and cute, they can be both agile and aggressive if disturbed. Their teeth and claws are very strong and sharp and, when handled, they will tend to clutch at anything within their reach. Take care to avoid being scratched or bitten. Koalas are best restrained for examination by placing them in a hessian sack and firmly holding them on the ground. This usually requires one person to hold the forearms, another to hold the hind legs and the third to do the examination. Cover the head (unless examining the face) and bring out of the bag only the parts required for examination at any one time, eg ear for ear tag identification, leg, or arm for examination. When done this way the animal is more easily restrained and the

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Figure 9. Restraint techniques for a koala. Larger individuals can be held by (a) picking them up by the upper arms from behind, or (b) smaller individuals can be held by the scruff of the neck and rump.

claws are kept under control from scratching. Be careful that you know where the mouth is while the animal is in the sack, as if given the chance they will bite hard through the sack. Pouch young can be examined by holding the mother in a hessian sack on the ground or on a bench, exposing her lower half for examination (holding the head and upper arms firmly in the sack). While one person is keeping the forearms under control, a second is holding the legs down, allowing a third person to open the pouch to check for pouch young. If required, measurements can be taken of the pouch young to estimate its age and to chart its growth. Back young should be removed from the mother, measured and then returned. If an animal has been hand-raised and is accustomed to handling they can generally be carried on the body with the arms gripping your shirt and the rump supported so that the koala doesn’t need to hold as strongly to your clothing. It is often advisable to wear a jumper when carrying a koala in this way as their claws will easily go through a shirt, particularly if the koala becomes frightened. Young animals can easily be carried by giving them a large stuffed toy or teddy to hold onto.

Examine the pouch to check for any pouch young and check the body for any wounds. Although the nails of koalas are generally quite long, they do not require trimming as they must be sharp to climb trees efficiently.

7.5 Release The best way to release the koala from a hessian sack is by opening the sack facing the base of the tree trunk, one to three metres away. When the koala leaves the sack it should run straight to the tree, although it may choose another trunk. Animals being held are best released by standing next to the tree you wish them to go to, ideally at a fork, and moving the koala’s arm closest to the tree from your shirt or jumper to the tree. Then move the other arm across to the tree while at the same time lifting its bottom over to the tree. Often the koala will begin moving itself onto the branch by leaning over to the branch and reaching out either before or after the first arm has been moved across. If this occurs, keep supporting the bottom and carefully lift the koala over to the branch or fork.

7.4 Weighing and examination

7.6 Transport requirements

During an examination, the animal should be weighed by placing it in a hessian sack and weighing it with either hanging spring scales, usually 5 kg, 10 kg or 20 kg or, preferably, on electronic scales as they are more accurate. If using spring scales, use the same set every time to avoid any differences between scales. Check the stomach to make sure it isn’t too hard which may indicate a build-up of gas, and pinch the skin to test for dehydration.

The conditions for the transport of koalas have been formulated to maximize the welfare of koalas involved in overseas transactions. The conditions set by Environment Australia provide the framework for the transport of koalas. A full list of the conditions for the overseas transfer of koalas is available in ‘Conditions for the Overseas Transfer of Koalas’ published by Environment Australia.

Koalas

7.6.1 Box design Each koala should be transported in a solid framed cage with inside measurements of 1000 mm (length) by 820 mm (breadth) by 1040 mm (height). The cages should have removable, leakproof metal drop trays fitted at the base. Sides and top must be of stout wire mesh and fitted with light hessian or shade cloth covers. Further specific details of the box design can be found in IATA (1999). 7.6.2 Furnishings At least one or two fork branches are required so the koala can sit during its transportation. These need to be securely fixed to the box to prevent them becoming dislodged during handling and shipment. Local transport, within one to three hours, does not require such extensive boxes or the need for forks.

the Queensland Wildlife Parks Association has set strict guidelines. Whether the visitor is handling the koala or just standing next to it for photos, it is imperative the koalas are chosen based on their temperament and that they are conditioned from weaning for handling or close human positioning. It is also important that the koala is observed constantly, particularly if a visitor is holding it, to assess its level of stress. 7.7.1 Signs of stress (derived from Booth 1989) Although it is not recommended to use koalas for handling or photography, if they are being used like this they should be monitored for signs of stress at all times. These include: ■

■ ■

7.6.3 Water and food Although koalas generally don’t drink, a stable dish of water should be placed in the box. Three or four shortened branches of tips should also be placed in a modified shortened leaf pot filled with water. Depending on the length of the flight, the leaves may need to be changed at least once. Water dishes are not usually required for short journeys (one to three hours). 7.6.4 Animals per box One koala per box. Females with pouch young should generally not be transferred unless only recently born, ie attached to the teat. 7.6.5 Timing of transportation Overnight is preferable as it is generally cooler. 7.6.6 Release from box When releasing the koala from the box, place the box in the exhibit next to the base of a tree. Completely open or remove the door to the box and allow the animal to leave the box when it feels ready so it has the opportunity to explore its surroundings and climb a tree at its leisure. When the animal is up a tree the box can be removed from the enclosure. Alternatively, an experienced handler can lift the animal out of the box, place it onto or next to a tree and then allow it to climb the tree.

7.7 Koala handling and photographing by the public Koala handling by the public is not recommended and it is not permitted in New South Wales and Victoria. In Queensland, people are permitted to hold koalas, although

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Will not sit in branch, keeps coming to the ground and walking around Completely flaccid and tractable Often urinating and defecating Continuous ear flicking Signs of anxiety in the koala include hiccups, a low whining vocalisation, and a typical alarm posture (wide eyes, ears forward, spine very vertical).

7.7.2 Minimizing stress during handling (derived from Booth 1989) Stress can be minimized during handling or photographic sessions by observing the following: ■ ■

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Only using koalas with suitable temperaments Captive bred koalas are obviously the best, even better if hand raised There is no difference in males and females with respect to temperament Having responsible and experienced supervisors who will respond to the koala’s needs even when they are busy Minimal restraint gives best cooperation Close monitoring of the time individual animals spend in photo sessions Re-position tourist, not koala, for photo. Monitoring of body weight of koalas and giving individuals ‘holidays’ whenever a drop or insufficient gain is noted.

8. Health requirements Edited by Dr Rosie Booth

8.1 Daily health checks Each koala should be observed daily for any signs of injury or illness. The most appropriate time to do this is generally when the enclosure is being cleaned or when the branches

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are replaced, which is often when the koalas are more active. During these times, each animal within the enclosure should be checked and the following assessed: ■ ■

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Coat condition Discharges – from the eyes, ears, nose, mouth or cloaca Appetite Faeces – number of pellets and consistency Wrinkles – on the nose, suggesting dehydration Dirt around the mouth, suggesting dirt eating Changes in demeanour Climbing ability using all four limbs Wetness of the cloaca and rump Injuries Presence and development of pouch young by observation of the bulge in the pouch.

Koalas can be prone to infestations of large numbers of ticks, particularly around their ears. Ticks cause irritation and mild to severe anaemia and should be removed whenever animals are in reach (D. Speilman pers. comm.). During the summer months, koalas should be checked for signs of heat stress, which include lethargy, and the presence of loose, very dry skin on the nose (Drake 1982). Heat stress tends to occur at temperatures of approximately 35°C or higher, so they need to be checked regularly at these high temperatures. Heat stress can be reduced in hot weather by placing a sprinkler where it will spray the trees of approximately one-third of the enclosure (Drake 1982). The sprinklers can be left on day or night if required. The faeces can be checked for the numbers of pellets dropped (normally between 75–150), particularly in the case of sick animals and animals that are solitary. The consistency of the faeces should also be noted to see if there is any diarrhoea or soft faeces. Although the presence of runny faeces can indicate potential problems, very high quality leaves also cause it, particularly after a period when the leaf quality has not been optimal. It is important for consistency that the same keepers regularly inspect and weigh the koalas as they are more able to determine the subtle changes in the health of individuals. This includes behavioural changes, which may indicate the presence of a health-related problem.

8.2 Detailed physical examination 8.2.1 Chemical restraint Pre-anaesthetic fasting is not necessary as koalas are not prone to regurgitation, though if food can be removed up to six hours beforehand, this will allow the stomach to

empty (Vogelnest 1999). Sedation can be done using diazepam (Valium®) at 0.5–1.0 mg/kg intramuscularly in the thigh muscle or 0.5 mg/kg intravenously and will be adequate for minor procedures and transportation (Vogelnest 1999). A number of injectable agents have been used to induce and maintain anaesthesia. Tiletamine/zolazepam (Zoletil®) at 4–10 mg/kg intramuscularly or 2.5–3.0 mg/ kg intravenously provides heavy sedation to surgical anaesthesia and is the injectable agent of choice in koalas (Vogelnest 1999). Other agents include ketamine at 10–25 mg/kg intramuscularly, which provides heavy sedation to light anaesthesia but has poor muscle relaxation. Ketamine at 5–15 mg/kg and xylazine at 5 mg/kg intramuscularly provides heavy sedation to light anaesthesia and the xylazine can be reversed with yohimbine at 0.2 mg/kg intravenously (Vogelnest 1999). Inhalation anaesthesia is commonly used in koalas, with isoflurane or halothane in oxygen being used successfully. Intubation with a 3–5 mm tube can be used, although it is difficult. Muscle relaxation is good and recovery is smooth and rapid (Vogelnest 1999). The cephalic vein is usually used for intravenous injections and the thigh muscles are used for intramuscular injections (Voglenest 1999). It is also important that koalas are not given access to trees or other climbing apparatus until they are fully recovered from anaesthesia (Vogelnest 1999). 8.2.2 Physical examination Very placid animals that are used to handling and human intervention may be examined conscious. For short, non-invasive procedures where no analgesia is required (eg radiographic positioning), diazepam (Valium®) at 0.5–1 mg/kg IM or 0.5 mg/kg IV can be employed. In most cases, gaseous anaesthesia via mask induction and maintenance with Isoflourane and oxygen is used to facilitate full examination. The animal is induced on 4–5% and maintained on 1.5–2% Isoflourane. The physical examination may include the following: ■

Body condition – This can be estimated by palpating the muscle mass over the scapula (A. Reiss pers. comm.) (Table 4). Although changes in muscle mass will also be apparent on palpation of other areas (eg limb muscles and muscles of mastication) it is more difficult to accurately measure body condition and changes in body condition. Koalas very rarely become overweight and have virtually no subcutaneous fat. Only koalas fed a significant amount of energy-rich, non-eucalypt nutrient in their diet run the risk of becoming overweight. A

Koalas

Table 4. Condition index used for koalas. Condition Score

Definition

Attributes

Score 5

Excellent

Strong muscle tone. Obviously convex muscle masses on either side of the scapula. Scapula spine palpable on careful palpation.

Score 4

Good

Good muscle tone. Slightly convex muscles on either side of the scapula. Scapula spine easily palpable.

Score 3

Fair

Flat to slightly convex muscles on either side of the scapula. Scapula spine prominent on palpation.

Score 2

Poor

Slight dishing or concave muscles on either side of scapula. Scapula spine very obvious on palpation. Edges of scapula bone palpable.

Score 1

Emaciated

Noticeable dishing of muscles on either side of scapula. In very emaciated animals there may be almost no muscles palpable on either side of the scapula spine. In these cases the entire scapula will be palpable through the skin.

From A. Reiss pers. comm.

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‘normal’ koala in excellent body condition will still feel ‘bony’ if palpated over the ribs or hips. This method is undertaken by placing a hand across the koala’s shoulders. Locate the spine of the scapula, which runs from the top of the shoulder down towards the upper arm. The spine of the scapula is about 10 cm long in an adult koala and feels like the keel bone of a bird. The scapula itself extends like a plate on either side of the spine. The muscles of the scapula lie on either side of the scapula spine, and generally cover the whole of the scapula, so that the scapula underneath can only be felt in very thin animals. Palpate the muscles to the front and back of the scapula spine firmly with your fingers. Palpate both the length of the muscle (along the length of the scapula spine) and across the width of the muscle (from the scapula spine to the edge of the muscle). Judge the roundness of the muscles and also their tone. A koala in excellent body condition will have round, firm muscles which bulge in a convex fashion (outward) on either side of the spine of the scapula. As body condition deteriorates the muscles become smaller, flatter and eventually convex (dishing inwards) on either side of the spine of the scapula (very similar to pectoral muscles in birds). In a koala in poorer condition, the spine of the scapula becomes more prominent and easily palpable, and muscle tone decreases. The scapula itself will be palpable on either side of the scapula spine in very thin animals. Temperature – Normally 35.5–36.5°C (Connolly 1999); can be taken through the anus via the cloaca. Weight – Record and compare to previous weights. Trends in body weight of koalas give a good general indication of the animals’ state of health, provided age, sex and geographical location are taken into account. Animals in captivity should be weighed monthly to indicate trends. This may range from

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monthly for healthy animals to several times a week for sick or injured animals. Fluctuations of up to 400 g (in Victorian animals) may result from variable gut fill. If a consistent decline in weight occurs, a vet should be consulted, and supplementary feeding may be required (eg daily doses of Prosobee, Portagen or Triglyde)(Handasyde et al. 1988). Pulse rate – Normally 65–90 beats per minute at rest (Connolly 1999); taken over the femoral artery. Respiratory rate – Normally 10–15 breaths per minute at rest (Connolly 1999). Panting (rapid, shallow breathing with the mouth closed) is normal in stressed or excited animals. Fur – Check for alopecia, ectoparasites, fungal infections or trauma Eyes ➝ Should be clear, bright and alert ➝ Normal bilateral pupillary light response ➝ Normal corneal reflex ➝ Should not have any discharges Also check for the presence of lumps over body and auscultation of lungs Cloaca ➝ Should be clean ➝ Check for faeces around the cloaca Pouch ➝ Condition of the pouch ➝ Check whether lactation is occurring by milking teats ➝ If pouch young are present, record sex, stage of development, weight if detached from the teat and measure to determine age from growth curves if available Males ➝ Check testes – size (length, width, depth) and consistency (firm – not squishy) ➝ Extrude penis and assess ➝ Check the size and activity of the sternal gland.

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8.3 Known health problems A number of diseases are known to occur in koalas, the most common are shown below. More detailed information can be found in excellent reviews complied by Blanshard (1994) and Booth and Blanshard (1999). 8.3.1 Ectoparasites Cause – Various ectoparasites can occur on koalas including fleas (eg Ctenocephalus felis), ticks (Ixodes spp. and Haemophysalis spp.), mites (Austrochirus perkinsi, Sarcoptes scabiei, Demodex spp. and Notoedres cati) and blowflies (Booth and Blanshard 1999). Signs – Itching and fur loss; direct observation for ticks and fleas. Diagnosis – Visual observations or a skin scraping and microscope examination to identify the parasites. Identification of sarcoptic mange is made by taking skin scrapings or samples of the parakeratotic crust and confirming the presence of Sarcoptes scabiei mites or their ova. Treatment – Ivermectin injection at 200 ug/kg S/C or ararcidal washes (Booth pers. comm.). Prevention – Good husbandry and quarantine (Booth pers. comm.). 8.3.2 Endoparasitic worms Cause – The cestode (Bertiella obesa), the only common endoparasite of koalas, is found in the small intestine. Other incidental records of internal parasites include the nematodes Marsupostrongylus longilarvatus, Durikainema sp., Breinlia sp. and Johnstonema sp. (Booth and Blanshard 1999). Signs – Tapeworm segments may be visible on the outside of faecal pellets. Not obvious unless diagnosed. Diagnosis – Faecal flotation and the presence of eggs or proglottids (segments that make up the worms). Treatment – Usually treated with praziquantel (Droncit®)(Booth pers. comm.). Prevention – Generally not required, although annual worming with Droncit® can be carried out (Booth pers. comm.). 8.3.3 Protozoans Cause – Cryptosporidium has been found to result in the deaths of koalas due to duodentitis, enteritis and colitis. Toxoplasma gondii has also been recorded in captive koalas (Booth and Blanshard 1999). Signs – Signs of toxoplasmosis in koalas have been acute tachypnea, tachycardia, pyrexia, lymphocytosis or sudden death caused by disseminated infection (Booth and Blanshard 1999).

Diagnosis – Cryptosporidia may be detected in the faeces using specific stains. Toxoplasmosis is diagnosed by serological testing to detect rising IgG Toxoplasma gondii titre (Booth pers. comm.). Treatment – Antiprotozoal drugs such as trimethaprim/ sulphadiazine combinations may be used to treat cryptosporidiosis and toxoplasmosis (Booth pers. comm.). Prevention – Toxoplasmosis is prevented by avoiding all access to cats and cat faeces. 8.3.4 Bacteria 8.3.4.1 Chlamydia Cause – Chlamydia is a genus of bacteria that is responsible for reproductive diseases in a range of mammals (Handasyde et al. 1988). Two agents have now been classified: C. pecorum and C. pneumoniae, with both species causing an ocular and urogenital disease (Glassick et al. 1997). C. pecorum appears to be more prevalent and more virulent than C. pneumoniae, and combined infections suggest that cross-immunity does not occur (Booth and Blanshard 1999). These bacteria have been isolated from ovarian diverticula, ovaries, uterine tubes, uteri, median and lateral vaginae, urinary bladder, renal pelvis, penile urethra, urogenital canal, nasal septum and rectum (Brown and Woolcock 1988). They have also been implicated in a number of signs of disease including infertility, rhinitis, pneumonia, urinary cystitis, nephritis, cystic ovary, conjunctivitis and keratoconjunctivitis. These are often associated with the ‘wet bottom’ or ‘dirty tail’ syndrome (Brown and Woolcock 1988). The most common route of transmission is venereally, as Chlamydia is found in the penile urethra as well as the urogenital canal of the female. It appears that the level of stress may be critical in the establishment of disease in koalas. Therefore, stress should be minimized in order to reduce the potential for the disease to occur. Signs – Chlamydiosis in koalas can be present in three main syndromes (Booth and Blanshard 1999): 1. Keratoconjunctivitis – In chronic cases it is seen as a purulent discharge from both eyes. In severe cases there can be inflammation of the conjuctiva (delicate membranes that line the inside of the eyelids) with keratitis (inflammation of the cornea) and occasionally inflammation of the entire tissues of the eye (panopthalmitis). Koalas affected by this syndrome often fall prey to dogs due to vision impairment.

Koalas

2. Urogenital Tract Disease – This syndrome generally results in a severe inflammation of the urinary bladder (cystitis), and sometimes can include the urinary tract. This can be seen by a constant urine dribbling and generally results in a red brown stain on the fur of the rump (hence the name dirty tail or wet bottom). Koalas with this condition often become weak, lose their appetite and may die from malnutrition. 3. Reproductive tract disease – In females, one or both of the ovarian bursae (that surround the ovary) may distend with inflammatory exudate. Although the ovaries themselves are not cystic, this causes infertility. This syndrome is usually associated with a chronic low-grade cystitis (an inflammation of the urinary bladder). Diagnosis – The most reliable technique of detecting the presence of Chlamydia is by the analysis of conjunctival or urogenital swabs to detect chlamydial DNA by polymerase chain reaction (Booth pers. comm.). Treatment – Early diagnosis and initiation of therapy are important in the success of treatment. Chronic cases often don’t respond well to treatment and recurrence of clinical signs after treatment is common (Booth and Blanshard 1999). A number of antimicrobials have been used to treat conjunctivitis and/or cystitis in koalas. Treatment with enrofloxacin, chloramphenicol or fluoroquinolones and supplementary feeding to minimize weight loss associated with anorexia have been successful. At present there is no confirmed successful treatment for chlamydial disease in koalas. In captivity a number of animals, which tested positive to chlamydia, have not shown signs of the disease. Precautions – Strict quarantine procedures need to be enforced where captive colonies of koalas are concerned. Outbreaks of conjunctivitis, rhinitis or cystitis in captive koalas can spread quickly, and koalas in contact with infected animals are at risk (Brown and Woolcock 1988). Any animals new to the collection should be tested for Chlamydia and if positive should be kept isolated from ‘chlamydia free’ koalas. Sexual transmission is the major method for spread of urogenital disease, so it is critical to know the chlamydial status of breeding koalas (Booth pers. comm.). 8.3.4.2 Rhinitis/Pneumonia Complex Cause – A wide range of pathogens can cause respiratory disease in koalas. Bordetella bronchiseptica is one of the more significant respiratory pathogens and has been associated with outbreaks of disease in captive colonies.

Signs – Frequent sneezing or coughing, unilateral or bilateral mucopurulent nasal discharge, pharyngeal inflammation and regional lymph node enlargement may be apparent (Booth and Blanshard 1999). A harsh vibrating sound may be heard when breathing (stridor) and may indicate nasopharyngeal swelling or bronchitis. Extremely acute bronchopneumonia may lead to sudden death. Diagnosis – In rhinitis cases swabs from the nasal cavity may show abundant neutrophils (Blanshard 1994). Any dry, yellowish, powder or flaky material adhering to the outside edges of the nostrils should be treated with suspicion and checked for recent discharge. Pharyngeal inflammation may be evident with a laryngoscope, and the regional lymph nodes (submandibular, facial) may be enlarged (Blanshard 1994). Radiography can be used to confirm or rule out lung involvement, as it is often difficult to listen to the sounds of the chest (Booth and Blanshard 1999). Auscultation of the thoracic area is made difficult by the thick fur and small area occupied by the lungs. Swabs can be taken to identify primary or secondary microbial pathogens (Blanshard 1994). Treatment – Sensitivity testing is required to select the most appropriate drug due to the great variation in microbial isolates, however if severity requires immediate action then broad-spectrum antibiotics such as amoxicillin/clavulanic acid, trimethoprim/ sulfamethoxazole or chloramphenicol should be used (Booth and Blanshard 1999), pending the results of culture and sensitivity. Prevention – Vaccination with inactivated, cell-free extract of B. bronchiseptica, Canvac-BB (CSL) has been used with annual boosters to help in the prevention of disease caused by Bordetella (Booth and Blanshard 1999). 8.3.4.3 Septicaemia Cause – A number of gram negative pathogens have been isolated from koalas including Salmonella typhimurium, Salmonella sachsenwald, Morganella morganii and Escherichia coli, with the most likely route of infection being through contaminated leaves (Booth and Blanshard 1999). The resulting septicaemia may be the primary disease or secondary to another illness. Septicaemia from E. coli has been observed in emergent pouch young feeding on pap (Booth and Blanshard 1999). Signs – Lethargy, ataxia, nystagmus, flaccidity, localized tremor, convulsions and vocalisations can occur. It is an extremely acute illness with neurological signs and sudden death.

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Diagnosis – Septicaemia should be considered as a possible differential diagnosis in any koala showing neurological signs (Blanshard 1994). Body temperature may be elevated, normal or decreased and leucocyte counts can be greatly decreased (to as low as 0.1 × 109/L). Blood for culture should be collected as aseptically as possible by disinfecting the skin through which the blood is to be taken. When the blood is collected, replace the original needle with a new one before putting it into a vial (Blanshard 1994). Treatment – No cases of successful treatment are known, although survival time has been extended to 10 days by providing antibiotics and following a stringent protocol (Booth and Blanshard 1999). Prevention – As ingestion of leaves that are contaminated with pathogenic bacteria appears to be the primary route of infection, cut food branches should be prevented from touching the ground wherever possible (Booth and Blanshard 1999). 8.3.5 Fungus Cause – Cryptococcus is caused by Cryptococcus neoformans var. gattii and var. neoformans, a fungus. C. neoformans var. gattii is associated with Eucalyptus trees and their flowers and C. neoformans var. neoformans is commonly found in soil contaminated with bird excreta, particularly from pigeons (Booth and Blanshard 1999). Infection occurs after inhalation of the spores from the environment or, less commonly, by direct inoculation of the skin (Booth and Blanshard 1999). Signs – The most common signs are respiratory and neurological with nasal discharge, tachypnea, dyspnea, coughing and sneezing sometimes occurring. Diagnosis –Several techniques can be used in diagnosis including smears of aspirates that are stained with methylene blue, Gram stain or India ink. Other techniques include cultures of clinical samples collected onto Sabouraud’s glucose agar or birdseed agar and the latex cryptococcal antigen agglutination test which detects antigens in the blood (see Booth and Blanshard 1999 for more information). Treatment – Early diagnosis is important and failure is common. Mixed success has been found with azole antifungal agents such as ketoconazole and fluconazole (Diflucan® capsules) (Booth and Blanshard 1999; Connolly 1999). Intracanazole is probably the first drug of choice (and is less expensive than fluconazole). It is given by making it into a paste with Portagen® and administering orally with a syringe (Connolly 1999).

Prevention – The environment should be cleaned with 5% sodium hypochlorite solution, especially in enclosures with concrete floors (Booth and Blanshard 1999). Koalas can be monitored with the latex cryptococcal antigen agglutination test, which is highly sensitive and specific and allows early detection (Booth and Blanshard 1999). 8.3.6 Other diseases Other diseases found in koalas include tubulointerstitial nephrosis, neoplasia, dermatomycosis, gastritis, enteritis, dermoid cysts, rhinitis and necrobacillosis of the jaw (Brown and Woolcock 1988; Finnie 1988a; Booth and Blanshard 1999). An outbreak of sarcoptic mange was recorded in a colony of koalas that resulted in the death of several koalas as the mange was difficult to see under the thick fur. Two treatments of amitraz (as a 0.025% aqueous suspension) applied topically ten days apart effectively controlled the outbreak (Brown et al. 1981). 8.3.7 Stress It has been suggested that stress may be immunosuppressive and increase the risk of infections and the likelihood of overt disease such as chlamydia. Stressors including handling, disruption of feeding times, disruption of sleeping, overcrowding, separation of the sexes, controlled mating and weaning. Sick or injured animals are notoriously difficult to treat (Finnie 1988a). Treatment of a seriously ill koala is difficult because the animal generally does not eat, no matter how good the treatment. This causes death from starvation. In an attempt to overcome this, stress should be kept to a minimum and it may be necessary to hand feed or use multi vitamin B therapy to stimulate the appetite.

8.4 Chlamydia control The quarantine protocol for koalas is primarily aimed at preventing the introduction of chlamydia. However, following the protocol is likely to prevent the introduction of other diseases to the collection and will establish a comprehensive set of baseline parameters for each animal. A standard 30-day quarantine is recommended before entering stock facilities, all imported koalas should have the following checks (in priority order): 1. Thorough clinical examination including a full clinical history if available. The following should be noted – weight, identification, age, pouch check, physical abnormalities, teeth condition.

Koalas

Figure 10. The koala’s daily cycle of activity. Vertical hatched areas signify periods of feeding; stippled areas, periods of sleeping; unshaded areas, periods of resting; and areas shaded black, periods moving between trees. Taken from Lee and Martin (1988) with permission of UNSW Press. Illustrated by Simpson, Sue The Koala.

2. Chlamydial PCR from conjunctival and urogenital swabs. 3. Blood samples taken for body function (blood cell count and biochemistry) and chlamydia antibody serology (EDTA ∫ ml minimum, 2 × Serum gel tube 2 ml minimum). 4. Blood sample taken for cryptococcal antigen serology (Serum gel tube 2 ml minimum) if coming from areas where Cryptococcus is endemic. 5. Faecal flotation 6. Cryptococcus interdigital swab (in areas where Cryptococcus is endemic). All animals should be held in off-limits quarantine and monitored daily by keepers until all test results are returned negative. All animals should be checked and cleared by a veterinarian before they are introduced to stock facilities. All imports should be considered infective until proven otherwise. All handling of animals and their used feed and excreta is to be carried out by one person. Used feed is to be taken directly to the compactor and when carried on a trolley or electric cart, wrapped in plastic. Gloves, coat and rubber boots should be worn while handling quarantined koalas and their feed. These items of protective clothing are to remain at the off limits

quarantine area. A footbath of disinfectant renewed at intervals of 24 hours may be used instead of rubber boots. Keepers’ hands and forearms should be scrubbed with Hibitane® or iovone scrub after boots, gloves and coat have been removed in that order.

9. Behaviour 9.1 Activity Koalas generally rest and sleep in the forks of trees, but they are occasionally found stretched along a branch. On hot days the limbs are extended and often lie free on either side of the trunk. The animal may recline along the limb and hold its head free of its chest, exposing its belly. On cold, wet and windy days they sit with their backs to the wind, with their arms folded against the chest and legs drawn against the belly. These changes in posture have an important role in temperature regulation (Lee and Martin 1988). It has been consistently shown that koalas spend approximately 18–20 hours of each day resting or asleep, one to three hours feeding and the remaining time moving between branches or trees, grooming or in social

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behaviour (Fig. 10). Feeding episodes normally last from 20 minutes to two hours with four to six of these bouts per day. Feeding can occur at any time of the day or night, however there is a tendency for wild koalas to feed immediately before or after dusk or dawn (Lee and Martin 1988). In contrast, captive animals tend to habituate to the feeding routine and feed when the food is supplied, unless it is very hot.

9.2 Social behaviour In the wild, koalas are generally a solitary species. Females have home ranges of approximately one hectare with some overlap with the ranges of males and other females, and the occasional sharing of trees. Home range sizes are dependent on habitat type though males have home ranges that overlap with other males and females. Some males, usually the older and larger ones, have large home ranges while smaller males have home ranges that are similar in size to those of females. Though it has been suggested that koalas might defend some type of territory against other koalas, they do not appear to be territorial (Lee 1988; Lee and Martin 1988; Martin and Handasyde 1991, 1999). The vocalizations of koalas are diverse. Calls include the bellow, which is primarily used by the males, although females do occasionally bellow as well. Bellowing may be used by the males to attract mates in sparse populations and as a warning to other koalas in the area. Fighting males often use a harsh grunt. Other vocalizations include repeated squeaks of joeys that may serve to attract the mother’s attention. The wails, squawk, low grunt, snarls and screams of females probably serve as a defensive threat (Smith 1980a; Lee and Martin 1988).

9.3 Reproductive behaviour The beginning of the breeding season is heralded by an increase in the frequency of bellowing by males (Lee 1988). Male koalas scent mark trees by grasping the tree trunk and rubbing their chest (containing the sternal gland) up and down against the base of the tree trunk and branches as they climb. They also scent mark using urine, with both sexes occasionally urinating on the trunk or on the ground close to the tree. The use of scent marking may help to establish the dominance of the male and the reproductive status of the female (Smith 1980b; Lee 1988; Thompson and Fadem 1989). Encounters between males are sometimes aggressive and during these encounters one animal (usually the one entering the tree) rushes up to attack the second animal. The second animal either retreats to the end of the

branch, or races past the attacker and out of the tree. Sometimes the animal at the end of the branch tries to leave the tree, but is chased back by the attacker who is sitting on the same branch. If the attacker manages to reach the other animal, it thrusts one arm around its shoulders and grasps the elbow with its teeth (often causing deep wounds), so holding the second animal, or even pulling it from the tree. If the attacked animal leaves the tree, it is usually only chased a few metres before the attacker returns to the tree, where it often bellows and marks the trunk with secretions of the sternal gland. Occasionally, the resident male quietly retreats to the end of a branch as the intruder enters the tree, and the intruder ignores him. Dominant males become active at dusk and move from tree to tree, checking the status of females and fighting with and excluding satellite males from access to oestrous females. Dominant animals stay close to and repeatedly mate with females in oestrous. These activities generally decline as summer progresses and are not observed during the cold months (Lee 1988; Lee and Martin 1988; Martin and Handasyde 1991). Care needs to be taken if allowing males to mate with females that have out of pouch young, as the young can become dislodged and fall to the ground, resulting in exposure and/or spinal injuries (G. Underwood pers. comm.).

9.4 Bathing Although koalas should always be given access to water, they never use water for bathing.

9.5 Behavioural problems Koalas suffer from relatively few problems in captivity, however some hand-reared animals can become overly attached to human company, resulting in longer weaning times and the urge to climb on anyone who passes by (such as during cleaning).

9.6 Signs of stress Signs of stress, especially if acute, include restlessness, stupefaction, frequent urination or defecation, hiccups, low whining vocalizations and typical alarm posture (wide eyes, ears forward and vertical spine). Other signs include loud vocalizations, aggressive defence such as threatening, biting or scratching (this may be before, during or after a stressful event), head shaking or ear flicking (Spielman 1994). Other stress can result in trembling when young are separated from their mother, diarrhoea (soft pellets or watery) within 24 hours and usually lasting 24 hours (Spielman 1994). Signs of

Koalas

chronic stress include reduced food intake and reduced body weight. If the number of pellets produced each day falls below 100 then it may be a cause for concern (Spielman 1994). Further information on stress in koalas can be found in sections 7.7.1–7.7.2.

9.7 Behavioural enrichment Koalas generally don’t display stereotypic behaviour as they don’t have the energy to spare, sleeping 18–20 hours per day. Some individuals will pace near the keeper’s entrance prior to the set feeding times. Movement of individual koalas can be maximized and conflict minimized by ensuring adequate forks for feeding and resting and a number of cross branches (see Section 4.8).

9.8 Introductions and removals Animal introductions are normally done first thing in the morning to minimize any public reaction during aggressive confrontations, and to allow the whole day for animals to be observed before being left together overnight. After the introduction of a new animal into an enclosure it should be watched to check for any agonistic behaviour, which should decrease as it works out its place amongst the group. If the aggression continues after several hours the new animal should be removed.

9.9 Intraspecific compatibility Female koalas can readily be held with each other and one or more males. If they are held with more than one male, the dominance hierarchy that is established means that the most dominant male is likely to do most or all the breeding. In most institutions, knowing the paternity is important for the breeding programs so it is for this reason, rather than aggression problems that only one male is generally given access to a female at any one time. Generally, mature males are separated from each other to reduce aggressive interactions. This is particularly important during the breeding season, although if adequately separated and depending on the nature of the individuals, two or three male koalas can be housed together for significant lengths of time.

9.10 Interspecific compatibility Koalas have been exhibited with other species including echidnas Tachyglossus aculeatus, pademelons Thylogale spp., quokkas Setonix brachyurus, parma wallabies Macropus parma, various species of lizards and large birds such as magpie geese Anseranus semipalmata. They could potentially be displayed with other small macropods such as bettongs Bettongia sp. and potoroos

Potorous sp. Wombats are generally not compatible with koalas as they have been known to cause injuries by biting. If the other species are used they should be supplied with a soil or grass substrate and adequate hiding places through the addition of tussocks. They would also need adequate ground space so they can move around freely in the exhibit. With the exception of the echidna, these species are generally nocturnal and would probably not be seen regularly by the public.

10. Breeding 10.1 Mating system In the wild, the koala is normally polygynous, with a male having more than one partner during a single breeding season. There is strong evidence of ‘sneaky mating’ by subordinate males (Johnson pers. comm.).

10.2 Ease of breeding Koalas breed readily in captivity.

10.3 Reproductive status 10.3.1 Females Koalas are generally placed in several categories depending on their reproductive status. For females these include: ■

■

■

■ ■

■

Non-parous (females that have never bred) – pouch small with no skin folds, clean and dry, teats very small. Parous (females that have bred previously but not presently) – pouch is small but distinct, dry and dirty; the teats are slightly elongated. Pregnant – Pouch roomy, pink in colour and glandular in appearance, skin folds may be observed on the lateral margins of the pouch, which close over near birthing. Pouch young present – attached to the teat. Lactating (young absent from the pouch but still suckling) – pouch area large, skin folds flaccid, hair sparse and stained, skin smooth and dark pink, teats elongated. Post lactation – teats expressing only clear liquid and/ or regressing.

If pouch young are present there are a number of developmental stages and measurements that can be recorded and compared to existing growth curves (see Section 10.16), or used to establish new curves. These include:

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Developmental stages ■ Sex distinguishable ■ Tips of ears free ■ Papillae of facial vibrissae evident ■ Eyelashes visible ■ Eyes open ■ Fur visible – slight tinge, medium or well developed ■ Tips of first incisors through the gums ■ Riding on back ■ Eating solids ■ Self feeding ■ Independent Measurements (see Appendix 5) ■ Weight (g) – if not on teat ■ Head length (mm) – from the occiput to snout tip ■ Head width (mm) – maximum width across the zygomatic arches ■ Crown rump length (mm) – primarily for very small neonates ■ Body length (mm) – from snout tip to cloaca ■ Tibia length (mm) – from the hip to the bottom of the pes ■ Pes length (mm) – from the heel to the base of the longest toe, not including the claw. 10.3.2 Males The males develop a scent gland over the sternum, which starts to develop when quite small and may become quite bare.

10.4 Techniques used to control breeding There are three major types of breeding system or methods that can be used (O’ Callaghan and Blanshard 1991). Each has its advantages and disadvantages with respect to convenience, knowing the paternity of offspring and hence avoiding inbreeding. In some species, inbreeding has been found to result in male-biased sex ratios and a decrease in survivorship and/or growth rate. Evidence to date suggests that in some areas in the wild, such as on several islands, koalas are highly inbred, resulting in malformation of the testes in males. 10.4.1 Selective breeding method This method of breeding involves placing a single male and female koala together. This system appears to be most effective when the male and female koalas are kept separate and placed together when the female is in oestrous (O’Callaghan and Blanshard 1991).

10.4.2 Harem breeding method This system involves a single male being placed in with a group of female koalas. This system allows the paternity of any offspring to be established for a number of females. Care needs to be taken not to let any particular male overbreed otherwise a loss of genetic variation can occur over the long term. 10.4.3 Random breeding method This method involves placing a number of male and female koalas into the one enclosure. This is not as good as selective breeding as there is little control over which animals mate. Paternity of most of the young will not be known, particularly as many matings will be unobserved (O’ Callaghan and Blanshard 1991). Determining the pedigree is therefore almost impossible except with the use of expensive techniques such as DNA fingerprinting (profiling). Female koalas housed in an enclosure with several males often get little rest during the breeding season as they are repeatedly harassed by different males. This can result in trauma and/or mortality of pouch young if present. Another disadvantage is that sub-adult females can be overpowered and mated, and give birth at a small size and weight (O’ Callaghan and Blanshard 1991). 10.4.4 Breeding group sex ratio Generally, a single male is placed with one or more females as discussed for the selective and harem breeding methods. This is so the paternity of the young is known and to avoid fighting by males trying to achieve alpha status and mating rights. Lactating and non-lactating females are normally separated to avoid accidental adoption of young by non-lactating females. Some females who have had their young removed for hand-rearing are often found with the young of other females, seemingly in an attempt to replace the loss of their own. 10.4.5 Artificial breeding More recently, significant research has been undertaken to successfully use artificial breeding technology to produce koalas with the use of artificial insemination. There are three fundamental components essential to the success of this technique: 1) semen collection using electroejaculation or an artificial vagina, 2) determining the most appropriate time for insemination and 3) determining the most appropriate site for semen deposition (Johnston et al. 1999, 2003).

Koalas

10.5 Occurrence of hybrids None.

10.6 Timing of breeding

10.9 Ability to breed more than once per year Koalas can only raise one young per year.

There is a distinct breeding season.

10.10 Nesting requirements

Northern Australia Mating period: July–April (O’Callaghan 1996). Birth period: August–May (O’Callaghan 1996).

None needed.

Southern Australia Mating period: September–February (Lee and Martin 1988). Birth Period: October–April (Lee and Martin 1988).

There is no specific diet required during breeding, though even greater attention should be given to the quality of eucalypt leaves provided.

North America Mating season: March–May (Thompson 1987).

10.7 Age at first and last breeding 10.7.1 Males Males are capable of reproducing at 18 months of age, but in the wild most are prevented from gaining access to females by older and larger males (Martin and Handasyde 1991). It appears that wild male koalas may do little mating before they are fully physically mature at four or five years of age. In captivity, males as young as 16 months have been observed attempting to mate mount, and have successfully produced young at 18 months of age (Thompson 1987). 10.7.2 Females Females occasionally have their first young when they are about 18–24 months of age in the wild (births have been observed in a female from 12 months in captivity) (O’Callaghan 1996) when they approach adult size, but this young rarely survives pouch life. Most females first breed towards the end of their second year/beginning of their third year in the wild and may produce one young each year up until 10–15 years of age (Gall 1980; Thompson 1987).

10.8 Ability to breed every year Males are able to breed every year. The largest number of matings observed in a season is eight, although the libido of the males generally drops after four or five matings in captivity (O’Callaghan 1996). Females are able to breed every year. A female typically cycles 51 days after the first mating of one cycle if she failed to give birth. A female will only mate once during the cycle regardless of whether the mating was successful and will cycle up to five times in a breeding season (O’Callaghan 1996).

10.11 Breeding diet

10.12 Oestrous cycle and gestation period The koala is unusual amongst marsupials in that ovulation appears to be induced by the physical act of coitus (S. Johnson pers. comm.). The average length of the oestrous cycle is about 33–36 days, with the duration of oestrus being approximately 10 days (Handasyde 1986; Johnston et al. 2000). Previous estimates of oestrous cycle length have been based on non-mated, presumably anovular, oestrous cycles which had a duration cycle of approximately 33 days (S. Johnson pers. comm.). Females are polyoestrous, and if not mated return to oestrus after approximately 50 days (Johnston et al. 2000). Oestrous is determined on the basis of behavioural clues, which include: an increase in activity; jerking or convulsive movements that resemble hiccoughing (this involves the female clinging vertically to a tree and then jerking the whole body, less often the upper part alone, vigorously about once per second); a decrease in appetite; weight loss; bellowing vocalizations and occasionally mate-like mounting behaviour (Smith 1980c; Thompson 1987). This behaviour normally lasts from one day to two weeks and normally stops once copulation has occurred (Thompson 1987). Once successfully mated, the gestation period is 33–36 days (Handasyde 1986; Johnston et al. 2000).

10.13 Litter size Approximately 65–73% of adult females breed per year in the wild, each producing a single young, although very rarely two young may be produced (Martin and Handasyde 1991). In captivity, 50–70% of females breed each year, depending on their age, with conception rate decreasing once they are over seven years old and falling to 20% for females over 13 years of age (O’Callaghan 1996). It is presumed that the female is unable to rear two young at the same time successfully to independence (Lee 1988; Lee and Martin 1988; Martin and Handasyde 1991).

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10.13.1 Number of young surviving Koalas have an approximately 70–90% juvenile survival rate in captivity, however this varies with age, being lowest for females 9–10 years old and highest for animals 11–12 years old (O’Callaghan 1996). The time of highest pouch young mortality is in the first three months of life, before it is obvious from the physical appearance of the pouch that it contains a joey, so some joey losses may go undetected (O’Callaghan 1996). If the young is lost, the female has a 70% chance of losing any subsequent joeys (O’Callaghan 1996). More recent information on koalas in south-eastern Australia found survival rates for dependent young are 86–96% for the period from birth to permanent pouch emergence and 88–100% for the period from first permanent emergence to the completion of weaning (Martin and Handasyde 1991). A number of practices can be implemented to reduce the death rate of koalas (O’Callaghan 1996). These include: ■

■

■

■

■

■

Separation of males away from females, as males can increase the level of stress in the female and dislodge the joey while trying to mate. Grouping females with same age young together as joeys can die if they climb onto a female that is not lactating or has a very small pouch young. Isolating females with pouch young so that neither the mother nor the young is interfered with by other koalas. Pouch observation by feeling the young from inside or outside of the pouch to determine its approximate size and growth rate, and checking to make sure the pouch is moist and not wet and does not contain yeasts or bacteria. Observation of young, looking for ruffled fur, head tilt, and eyes. Transferring pouch or back young, if the mother dies, to another female that is lactating.

10.13.2 Pouch checking Females’ pouches should be checked regularly and this can be done by inserting an index finger into the pouch from between the animal’s hind legs whilst she is walking along a branch (Drake 1982). This method is gentler and less traumatic than if the female has to be caught.

10.14 Age at weaning The joey at commencement of weaning onto Eucalyptus is approximately 900–1000 g (NSW race) and would be 5–6 months of age. The adult male should be removed when the female is first observed to have a pouch young. The young koala should be removed from the female

when independent, to avoid metabolic drain and prolonged lactation, and to allow the female time to recover condition before giving birth again.

10.15 Age at removal from parent The joey remains with its mother until it is about 12 months of age, at which time it weighs approximately 2 kg (Smith 1979; Lee and Martin 1988; O’ Callaghan 1996). If another young is born about this time, the bond between the yearling and mother abruptly breaks down. Yearlings attempting to suckle are treated aggressively by their mother, and although often found in the same tree as the mother, they are no longer tolerated on her back. Yearlings are sometimes found with a surrogate mother, an adult female without a back young, and even occasionally with a male courting the mother. Yearlings usually stay in the general vicinity of the mother for another year. Some females settle in a home range nearby to the mother. These females may be mated by their father in subsequent breeding seasons. Young males usually disperse from their mother’s home range at about two years of age and may roam for the next two or three years before settling (Martin and Handasyde 1999).

10.16 Growth and development The young neonate is 0.5 g and 19 mm long when it is born and bears a strong superficial appearance to other marsupials (Lee and Martin 1988; Lee 1988; Martin and Handasyde 1991). The forelimbs, shoulders and lips are well developed, and the digits are equipped with claws. By contrast, the toes of the hind limbs are buds. The relationship between head length and age in days was developed for Queensland koalas by Blanshard (1991) and Victorian koalas by Martin and Handasyde (1991)(Fig. 11). Smith (1979), Thompson (1987) and O’Callaghan (1996) examine the relationship between age and weight for Queensland koalas, while Martin and Handasyde (1991) developed a growth curve for weight with age for Victorian koalas (Fig. 12a). It should be noted that these figures contain data for both Queensland and Victorian animals and though they remain relatively similar while juveniles, their weights diverge greatly as adults (from approximately 400 days) with Victorian koalas being considerably larger (Fig. 12b). Woods (1999) uses head length and weight but the location (and hence adult size) is not known. Development of pouch young is very slow and young remain in the pouch for five to six months where they rely only on the mother’s milk. When the joey is approximately five to six months (170–210 days; Thomson 1987) of age the female produces a second type of faeces (known as pap), which the joey eats over several

Koalas

140

Head Length (mm)

120 100 80 60 40 20 0 0

100

200

300

400

500

600

700

Age (days) Figure 11. Growth in head length for koalas. Derived from Blanshard (1991) and Martin and Handasyde (1991).

days up to a week. This is to introduce the appropriate gut flora and bacteria into the developing juvenile’s stomach and caecum so that it can begin to digest eucalyptus leaves and be weaned from its mother (Table 5). The joey commences eating eucalyptus leaves at five to six months of age and will progressively consume greater amounts of leaf until it is weaned at around 11-12 months after birth.

11. Artificial rearing 11.1 Housing As with all native mammals that have been taken into care, minimizing stress is a major consideration. Choosing suitable housing can help to create a stress free environment. To achieve this, several factors should be considered including: ■ ■ ■ ■ ■

Securing the area from children and animals Maintaining the area in a hygienic manner Escape-proofing the area Clearing the area of obstacles and hazards Ensuring the area offers shelter from the weather and noise

For joeys under six to seven months of age, an artificial pouch is needed which simulates, as closely as possible, the security and warmth of a natural pouch. Natural fibre products such as wool and cotton are recommended as they retain temperature better and have a reduced chance of causing rubbing sores. Place the joey in a cotton pouch, then place this pouch inside a woollen pouch. A basket or rucksack with suitable heating, clean pouches and blankets, and the provision of a soft toy for the joey to hold onto provide an ideal environment, which is also easy to transport. At Healesville Sanctuary a

Table 5. Timetable of major developmental stages in juvenile koalas. Stage of Development

Age Range

Head out of pouch

162–203

First total emergence

166–224

Maternal faeces eaten

171–213

First total emergence

175–182

Eucalypt leaves eaten

192–232

First seen off mother

214–275

From Thompson (1987) and Blanshard (1991)

hotbox is used which has a 25-watt lamp underneath the base that maintains an even temperature. The joey is placed on its toy and then into a pouch made of a sewn up windcheater, with woolly inlays/blankets. Alternatively, the joey can also be placed onto a teddy then into a cotton liner bag and woollen bag if cool. This can then be placed in a haversack and hung close to the perch, which allows the joey to climb on and off the perch (A. Gifford pers. comm.). The pouch is changed when soiled, which is usually after each feed. The use of a soft toy as a substitute for the mother koala has been found to be very successful. From the onset of hand-raising, the joey is placed onto the soft toy, which it clings to eagerly. This eliminates the need for the hand raiser to constantly carry the koala joey with them as the soft toy offers companionship and warmth. The soft toy also makes the introduction of the koala into new environments less stressful as it can go as well. Even when hand-raised koalas are fully-grown, they often readily accept climbing onto the soft toy which makes it easy to carry them. When the joey is older, place two thick-barked branches in an upright position, making sure they have a

173


(a) 3500

Males

3000

Females

Weight (g)

2500 2000 1500 1000 500 0 0

50

100

150

200

250

300

350

400

Age (days)

(b) 14000

Males - Vic Females - Vic Males - Qld Females - Qld

12000 10000

Weight (g)

174

8000 6000 4000 2000 0 0

500

1000

1500

2000

Age (days) Figure 12. Growth in body weight of the koala. a) up to 400 days and b) up to 1825 days. Derived from Thompson (1987), Blanshard (1991), Martin and Handasyde (1991) and O’Callaghan (1996).

good fork at approximately chest height for the koala to sit in. A horizontal branch connecting the two uprights will create a good climbing structure. By 12 months of age the koala should be in an outdoor enclosure with various climbing structures. When the joey is old enough to go into a larger enclosure with forked branches it can be placed with a soft toy in the fork until it is confident enough to leave the toy.

11.2 Temperature requirements Furless joeys need special attention to ensure they maintain a constant temperature. A temperature of about 32–34°C for unfurred animals is reduced to 28–30°C when they have fur. These temperatures can be maintained with the use of a heating pad or hot water bottle. Use a minimum/maximum temperature gauge

with a plastic-coated probe that can be placed next to the joey, as this will ensure that the temperature can be monitored. Heat pads should be thermostatically controlled to avoid overheating (J. Cowey pers. comm.). Furred joeys can be given a heat pad in an upright position in a corner of their basket, which will allow the joey to move to and from the heat source to adjust its own temperature. By eight to nine months of age, heating should only be needed at night and by 11 months of age the joey should be completely weaned from heating.

11.3 Diet and feeding routine 11.3.1 Natural milk The composition of koala milk differs from the general marsupial pattern, with the exception of the brushtail possum Trichosurus vulpecula and ringtail possum

Koalas

Table 6. Concentrations of the major constituents of koala milk. Total Solids (%)

Carbohydrates (%)

Lipids (%)

Protein (%)

Calcium (mg/l)

Iron (mg/l)

28.3–33.6

1.0–8.8

10.1–18.0

5.5–12.5

4000–5100

13.0

From Green (1984), Marshall et al. (1990) and Krockenberger (1996)

Pseudocheirus peregrinus that are also folivorous (Krockenberger 1996). Milk solids decrease from a peak of 33.6% at 220 days to 28.3% at 300 days, after which they remain relatively constant, in contrast to the solids of most marsupials, which rise at this time. Lipids provide a major source of energy in early to mid lactation but do not rise at pouch exit, unlike lipid levels in other marsupials that rise sharply at pouch exit to high levels in late lactation (Krockenberger 1996). Total carbohydrates of koala milk range from 8.8% at day 140 to decrease steadily to 1.1% at 380 days. Oligosaccharides comprised more than 90% of the total carbohydrates during most of the lactation period, but decreased to less than 5% towards the end of lactation when there was an increase in lactose (Marshall et al. 1990; Krockenberger 1996). Concentrations of sodium, potassium, calcium, and phosphorus are within those typically found in marsupials, however copper was not detected, suggesting its concentration is less than 2mg/L (Marshall et al. 1990). 11.3.2 Milk formulas Various low lactose formulas can be used for hand-rearing young koalas. These include: ■

■

Biolac, which has three formulas – M100 with 2–5 ml of canola oil per 100 ml for furless joeys; M150, a transitional milk to use when dense fur has developed; and M200, which contains elevated lipid in the form of canola oil, for use when the animal produces solid dark pellet droppings. When the joey is nearing weaning, 2–5 ml of canola oil is added per 100 ml of formula. Mixing the formulas is the way to make the transition from one formula to another. The joey should be fed 10–15% of its body weight per day. Wombaroo Koala Milk – Charts are provided to assist in determining the type and volume to be fed. There are three formulas; the early lactation formula is given until the head first appears out of the pouch at approximately 160 days; a transition period occurs from 160–180 days and then the mid lactation formula is given to 250 days, when the young would normally be on the mother’s back, there is another

■ ■ ■

■

transitional period until 270 days when the late lactation formula is used. Di-Vetelact – 16 g per 100 ml of water Portagen – 28 g per 100 ml of water Portagen and Farex – use one tablespoon of Portagen and two tablespoons of Farex per 100 ml of water. If these ingredients are unavailable, a milk formula made from evaporated milk, boiled water and glucose is adequate for the short term. This is made with one part evaporated milk to two parts water and 10% glucose.

11.3.3 Feeding apparatus Very small joeys can be fed using a syringe fitted with bicycle tyre valve rubber, plastic intravenous catheter or 1-inch length of infant gastric feeding tube (Bellamy 1992). However, most koala joeys will be large enough to be fed with a plastic feeder bottle (50 or 100 ml) and a special wombat type (a) teat (Austin 1997) or a T4 Biolac teat. The teat should be punctured with a hot needle (A. Gifford pers. comm.). For very young koalas, a small syringe with a tapered piece of rubber attached to the end works well to provide adequate food. As the joey grows, a catheter tip syringe can be used. Alternatively, a plastic bottle and koala teat can be used. A 10 ml syringe works well for older joeys, with the tip placed in the corner of the mouth and 0.1 ml injected at a time (J. Cowey pers. comm.). The milk formula should be heated until it is approximately 36°C (not too hot that it burns the mouth of the joey). The milk is given to the joey with the use of a plastic bottle and a rubber teat. Each day approximately 10–20% of the bodyweight of the individual should be given per 24-hour period (or the amount specified on the Wombaroo chart for a joey of that age). This amount is divided up into the number of feeds given per day. Do not overfeed Wombaroo or diarrhoea may result. Initially only one person should feed and handle the koala. Once settled, two people can be used if required. Feeding is initially required every three hours regardless of the age of the joey, until the animal is well established. Once the joey has been established and is feeding well the time between feeds can be increased if the joey is over 180 days old (Table 7). The number of

175

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feeds should also be varied depending on the health and keenness of the joey. For example, a poor feeder may require more frequent small feeds than an animal of the same age that feeds well.

Table 7. The number of feeds per day for different aged koala joeys. Age (days)

11.3.4 Feeding routine When deciding on a feeding regime for the koala joey several things need to be considered: ■

■

■ ■ ■

Read and understand the manufacturer’s guidelines for making the milk formula How much the animal can comfortably consume in one feed The age of the joey Whether it is eating leaves yet Whether it is dehydrated and needs more frequent fluid intake.

When a young koala comes into care it is important to assess its age and whether or not it has consumed pap already. Generally, if a young koala has started eating leaves, it is assumed that it has already eaten pap from its mother. A way of determining if a koala has consumed leaves (and therefore pap) is by checking for brown staining on the erupted cheek teeth or plant cell walls in faecal smears. If the joey has not consumed pap prior to acquisition it is important that, at about six months of age, it is offered substitute pap. This can be done by collecting pap from a female koala with pouch young of similar age. If pap is not available, then collect fresh faeces from an adult koala and mix it into a slurry. Offer the joey as much as it wants over a four-week period. It can also be included in the milk for bottle feeds. When joeys start eating leaves for the first time, they often need the carer to sit and hand feed them, as they do not move about searching for leaves by themselves. Normally they would come into contact with leaves as their mother moves about. As the joey starts eating eucalyptus leaves, the quantity of milk formula will remain the same but the number of feeds will vary depending on how many leaves have been eaten. During more advanced stages of leaf eating (300–365 days), when the joey is eating a lot of leaves (or should be), it is important to make sure they get a good milk feed in the morning and at night. This should encourage them to eat the majority of eucalyptus leaves during the day. Hand-raised joeys are often fed on milk for slightly longer than a parent raised animal to ensure they can cope with any extra stresses and have a good body weight before weaning. To help encourage the

Number of Feeds

90–180

8

180–270

6

270–300

4

300–365

2*

*Reduce slowly to two feeds and then one feed depending on the quantity of eucalyptus leaves eaten.

joey to eat them, leaves can be dipped in the milk formula first (J. Cowey pers. comm.). It takes a while before newly acquired koala joeys are used to being fed, so during this adjustment period it is often necessary to wrap the animal in a clean cloth, with only its head exposed. Joeys often feed better initially if their eyes are covered, as it removes the fear and distraction of the carer. This technique tends to make the feeding process a lot easier. Koalas appear to gain a taste for the milk formula as they are ‘weaned’ onto it. Hand-raised juvenile koalas appear to be able to digest leaves without trouble even though they appear not to have had access to the soft faeces from their mother (Finnie 1988b). Soft faeces or pap is a different type of faeces produced by the female when her joey is about six months old. The joey eats these faeces and it is suggested that they provide it with the adequate bacteria for it to start the weaning process and be able to digest eucalyptus leaves. If giving the joey crushed up faeces, screen them first to ensure you are not introducing any unwanted parasites to the joey.

11.4 Specific requirements When the koala first arrives: ■ ■ ■ ■ ■ ■

■ ■

Minimize handling Have it examined by a vet Obtain its history Take an initial body weight and measurements Estimate its age Do not attempt to feed it until it is warm as it may aspirate milk Organize bedding or a hot box Organize the appropriate diet

Initially, the animal should be weighed daily to ensure weight gain. Once it is fully furred and approaching weaning it can be weighed every two to three days to ensure it continues to gain weight. If it fails to gain weight or there is a change in the rate of gain this should be

Koalas

investigated by a veterinarian and the diet investigated if necessary. The skin of unfurred and slightly furred young should be kept moist with the use of Sorbelene cream (not with added glycerine) so that it does not become dry and cracked (George et al. 1995). Baby oil does not appear to be properly absorbed and tends to stay on the skin surface where it rubs off and is absorbed by the liner bag fabric (George et al. 1995). When first brought in for hand-rearing, the joey may be dehydrated, if so it can be given plain boiled water, with 5 g (one teaspoon) of glucose to 100 ml of water or 1 g of electrolyte replacer if available (Austin 1997). It is important to warm the joey prior to feeding to avoid the risk of inhalation pneumonia. If this is taking too long, give fluids subcutaneously and bottle-feed later. If the joey is really cold, place it in a warm water bath and dry it off rather than putting it in a hot box (J. Cowey pers. comm.). Stress is a major problem in the successful rearing of native mammals and can be fatal. It is important to minimize noise, not to overhandle animals and maintain high standards of hygiene (A. Gifford pers. comm.).

■

The developmental stages and measurements outlined in Section 10.3.1 should also be recorded on a weekly basis if possible. During the hand-rearing process, information should be recorded including date, intake of food at each feed, vet examinations, body weight and other body measurements if possible. This information serves several purposes, such as allowing a comparison with growth curves to assess progress and establishing new growth curves for species where they do not already exist.

11.6 Identification methods Generally not needed, however an implant chip can be used once the joey is furred.

11.7 Hygiene Maintaining a high standard of hygiene is critical to the survival of the koala joey. Emphasis needs to be placed on the following: ■

11.5 Data recording When an animal is first brought in for hand-rearing, its sex and approximate age, using growth charts, should be recorded. During the hand-rearing process a number of important pieces of information should be recorded. This information serves several purposes, including providing important background information such as food consumption data which will assist a veterinarian reach a diagnosis if the animal becomes sick or fails to grow or gain weight. It also allows a comparison with growth curves to assess progress (see Section 10.16) and enables growth curves to be established for measurements where they do not already exist. The following information should be recorded on a daily basis:

■

■ ■

■ ■ ■ ■

■ ■

■ ■ ■ ■

Date Time when the information is recorded Body weight to the nearest 1 g if possible; this can be done by weighing the koala while it is on its soft toy General activity and demeanour Characteristics and frequency of defecation and urination Amount (g) of different milk offered Milk consumption at each feed Species of leaves offered and eaten Veterinary examinations and results

When pap or faeces was offered

■

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Clean pouch lining at all times. Older joeys may be able to be trained to urinate on newspaper by keeping a piece of newspaper with the smell of urine on it. The joey is placed on the paper while it is clinging to the toy. Slowly turn the toy until the koala’s bottom is touching the paper. They usually place their rear legs on the paper, urinate and jump back on their toy. When joeys are approximately seven months old they tend to come to the ground on their own accord to urinate and continue to do so for several months (A. Gifford pers. comm.). Personal hygiene – wash and disinfect hands before and after handling the joey. Use antibacterial solution for washing hands with furless joeys, as their immune system is not well developed. Wash hands between feeding different joeys. Use boiled water when making up formulas for very young joeys. Clean spilt milk formula, faeces and urine from the joey’s skin and fur as soon as possible, and then dry it. Wash all feeding equipment in warm soapy water and sterilize it in a suitable antibacterial solution such as Halasept or Milton, or boil it for 10 minutes. Once sterilized, the equipment should be rinsed in cold water. Many carers store the teats and bottles in the fridge after they have been disinfected (J. Cowey pers. comm.). Only heat up milk once and discard leftovers.

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Avoid contact with other animals unless you are sure they pose no health risk. Stimulate to toilet before or after feeding. As with other marsupials, toileting can be done by applying warm water to the cloaca using cotton wool to stimulate urination and defecation. This allows the animal to keep drier and warmer in its pouch. If furless, cover the joey’s body with Sorbelene cream after each feed until fur appears. Use a new pouch liner after each feed. Change the water of leaf pots daily.

11.8 Behavioural considerations Koalas become highly attached to the person who is raising them and can resist weaning, with the result that it takes much longer than it would if the parent was raising the young. It is important not to allow the koala to become overly dependent on humans. The use of the teddy bear minimizes the bonding of the koala to the rearer as the joey becomes more attached to its scent on the teddy and should willingly climb onto it for anyone (A. Gifford pers. comm.).

11.9 Use of foster species Not recommended.

11.10 Weaning At about six to six and a half months of age, after the consumption of pap, the joey should be feeding on eucalyptus leaves. A general rule is to decrease the formula by 5% per week as long as the joey continues to gain weight at a minimum of 5–10% of body weight per day (J. Cowey pers. comm.). The joey should be given the fresh light green tips of leaves from at least three species of eucalypt per day, although they do also eat old leaves (pers. obs.). The leaves should be placed in leaf pots filled with water to keep them fresh. Make sure the leaf pots always have browse in them as juvenile koalas may fall into them and get stuck. It is very important to provide a variety of fresh green leaves from different species and these should be changed at least twice per day (and

should be sprayed with water several times per day, especially in hot weather). The leaf pots, or at least its opening, should be small enough so that the animal cannot fall into it and drown (J. Cowey pers. comm.). The joey should be completely weaned by approximately 11–12 months of age. Often the koala will start to refuse the formula anyway at this time and start weaning itself. The basic rule is to decrease the milk content as the leaf intake increases. At weaning, fresh water should be supplied.

11.11 Rehabilitation and release procedures When the release stage is approaching, start collecting leaves from the future release site to familiarize the koala with those species. The release site should be in an area with a healthy residential population of koalas and be away from roads, residential areas and associated dogs.

12. Acknowledgments This husbandry chapter was put together from two existing manuals. One of these was produced by Stephen Jackson and the other, on the koala management at Currumbin Sanctuary, by Des Spittall, Liz Romer and Katie Reid. Thanks go to the following people for all their help. Bronwyn Macreadie from Healesville Sanctuary, members of the Australian Mammal Division at Taronga Zoo and Geoff Underwood from Tidbinbilla Nature Reserve for making valuable suggestions to these husbandry notes. Thanks also to Dr Larry Vogelnest, Dr Howard Ralph and Dr Rosie Booth for their assistance in the veterinary component of the notes. Thank you to Joadie Lardner-Smith, Fiona Cameron, Annette Gifford and Bronwyn Macreadie for putting together the notes on hand-rearing. Thanks to Dr William Foley for his valuable comments on the diet. Finally I would like to thank Dr Kath Handasyde and Dr Steve Johnston for all their help in reviewing this document, providing further information and making numerous valuable suggestions.

Koalas

Addendum 1. The management of eucalyptus plantations for koala fodder From O’Callaghan 1999

This summary sheet information is presented as a guide to institutions wishing to acquire koalas or produce eucalypt fodder for other animals. Australian zoos that have exported koalas can provide additional information. Qualified horticulturists, experienced in eucalypt plantation management, should be consulted at all stages of plantation development. The growth rates of plantation eucalypts will vary depending on the climate, soil conditions, insect pests and harvesting rates. Growth rates must be taken into account when planning your plantation. Species of eucalypts from cold climates tend to grow more slowly.

Soil test for fertility; high soil fertility will save costs through less use of fertilizer and will generally produce highly palatable leaves. ➝ Avoid heavy clays and loose sands; a limited number of species will grow well on these soils. Existing vegetation: ➝ Don’t plant a plantation under a canopy of any species, as competition for light and water will hinder growth. ➝ Existing vegetation will give an indication of soil conditions, eg Ironbarks and Bloodwoods = poor soil; Redgums = fertile soils. Access to good, year round quality and quantity water supply for irrigation. Accessibility to the site in inclement weather, eg clays stay wet a long time. Surrounding land use that may cause damage to the plantation or leaf quality, eg fires, use of chemicals, smoke and ash. Aspect of land, eg avoid slopes that do not face the sun and slopes facing strong prevailing winds. ➝

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Successful plantations aim to produce high quality, palatable leaf by removing factors that adversely affect the growth of the tree.

3. Land preparation

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Plantations, although costing more initially in capital expenditure, are generally cheaper than the costs associated with roadside collection or purchase from commercial sources. Plantations provide a reliable and controlled supply of leaf fodder for koalas as well as other animals. Zoos and wildlife parks have an obligation to educate their visitors about the sustainable use of our natural resources. We have a responsibility to be environmental role models. Plantations allow absolute control of the quality of food being given to the koalas we care for.

2. Site selection Factors to consider when purchasing or selecting land to be used for plantations: ■ Distance to institution, ie travelling time = staff time and affects leaf quality. ■ Soil types and fertility: ➝ Check for salinity levels, generally eucalypts prefer low salt levels, although it varies from species to species. ➝ Check drainage as this will determine species selection; most species prefer well-drained soils. ➝ Select a soil type that suits 80% of the species you intend to grow.

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Land preparation aims to provide optimum conditions for tree growth by reducing competition for nutrients, light and water and any hindrance to root development. All existing vegetation should be removed except in areas that are not going to be planted; some existing specimen trees may be left to attract birds. Retention of vegetation surrounding the plantation is encouraged as it attracts birds into the area and reduces eucalyptus specific pest opportunities. Rows should be formed according to land contours to prevent erosion. Ripping of rows is essential to break up hard pans and compaction. All rows should be mounded to prevent waterlogging and to provide extended depth for root penetration. Rotary hoeing may be required to provide friable soil for root/soil contact, particularly when the trees are small.

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plantation palatability versus wild eucalyptus palatability. Plant at least five staple, ie preferred, species and three other species. The greater the number of species planted, the greater the flexibility in feeding the animals. New species and species for other climatic or geographic areas should be trialed first in small numbers as they may not grow well or be palatable. Select species according to soil type and conditions, eg wet soil for water loving species etc. Different eucalypt ‘types’ have different growth rates that generally relate to the amount of leaf on the tree (large amount of leaf = faster growth rates). Ironbarks and boxes tend to be slower growers than gums and stringy barks.

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Will depend on the size pieces and age of browse preferred, eg tips versus leaves, and the growth habit of each species. The closest plantings should be one metre and the largest gap between trees should be two metres. The space between rows needs to be large enough for maintenance, eg vehicle access moving, spraying etc, without causing damage to the trees. A koala eats between 400 and 1000 g (10% of its body weight) per day. The quantity will depend on the age of the leaf, moisture content, season, activity level of koalas, eg breeding, lactating etc, and the age and weight of the koala. A general ratio to plant is 1000 trees per koala.

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Trees selected should be tube stock. Whether to mix plant or block plant species will depend on the number of animals to be fed; block planting is recommended for ease of collection. Trees should be planted after being grown in tubes to promote straight root growth. This allows the tree to establish faster because the roots are facing downwards instead of having formed a ball. Trees must be removed from the growth pots as soon as possible as failure to do so can cause poor root growth and stem rot. Don’t stake trees for any reason. Staking can artificially support the tree and weaken root growth. Rubbing on stakes can also cause stem rot. Planting should occur late winter after the last frost. Consider vertebrate pest control, eg tree guards.

Research has shown that soil type and the amount of available nutrients in the soil determine leaf palatability. Koala leaf preference has been shown to be directly related to the percentage of nutrients to anti-nutrients (tannins etc) in the leaf. Research has shown that wild areas of high soil fertility have higher densities of koalas. Trees produce fewer anti-nutrients in fertile soils. These include tannins and cineoles that make the leaf taste bad and protect it from leaf insects. Important nutrients for good eucalypt growth are Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Copper (Cu), Sulphur (S) and Boron (B). It is important to have high N, high K and low P. Fertilizer should be applied twice per year. The quantity of fertilizer used is determined by harvesting rates. It is preferable to use organic fertilizers, but chemical fertilizers can be used if they are checked to ensure they do not affect leaf palatability. Soil test at least once every three years to determine effects on soil fertility. Feeder roots occur in the top 10 cm of soil so avoid excess watering after application. Don’t clump fertilizer as this may cause burning and tree death. Avoid fertilizing immediately before or after spraying with herbicides as this may cause a chemical reaction and affect tree growth.

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The ability to provide water to the trees is essential to eliminate drought as a limiting factor of tree growth. Dripper lines, T tape or overhead irrigation are possible. Overhead is preferable as there are fewer problems and the sprinklers wash the leaves regularly, removing any foreign substance. How much and how often to irrigate will depend on soil type and natural weather conditions. When trees are planted, they should be irrigated until well established, ie noticeable development or growth, usually around two weeks. After trees are established they should be stressed to encourage root growth. Stress the trees over the first year to the point where new growth starts to droop. At this point trees should be well watered. This will

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only need to be done two or three times in the first year. Irrigation on mature trees can be used to promote new growth in blocks.

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Competing vegetation is a major growth limiting factor through competition for light and, more importantly, nutrients. Grass is a major consumer of nutrients due to its fast growth rate. Weed control should ensure a one metre square area around the base of the tree free of vegetation. The two most effective preventive weed controllers are weed mat and mulch. When spraying weeds, use a non-residual herbicide such as Bioactive. Avoid sprays with surfactants as they are damaging to the environment. Take care when spraying young trees as green stem absorbs poison at 1/3 the rate of foliage.

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Trees must be at least 10 months post-planting, assuming you have planted trees two to three metres in height with good seasonal growth for harvesting. A trial comparing coppicing trees to pollarding trees showed that pollarding produced a branch suitable

for cutting faster than a coppiced tree. It also showed that far fewer trees died from being pollarded. Trees react to the stimulus of having branches removed. This allows harvesters to shape the tree how they prefer. Removal of a branch on a tree can often stimulate the tree to produce young growth on all the remaining branches. Trees are competing between themselves for light and this affects the extent of growth of the lateral branches. Individual pieces on a tree are also competing with each other and thinning loads are required to reduce timber production and increase leaf production on the tree. Trees should be harvested at a height that is comfortable for the person harvesting and above the height that maintenance equipment will cause damage. All harvesting cuts should attempt to be on a 45% angle to allow maximum exposure to sun and to encourage water runoff. Saws or similar equipment should always be used to harvest to prevent splitting of the trunk.

Lower branches and shoots should be removed to allow air movement at ground level through the plantation. Replanting all gaps and replacing all dead trees every two years will ensure continued leaf production. A major coppice of individual trees may be required if the bole at harvesting level becomes too large or if large amounts of dead timber are present. Because of the effect of constant, young growth, production and removal, the expected tree life will be greatly reduced, eg some tree species that usually live over 200 years may be old at 10 years in a plantation. Signs of this aging may be reduced leaf production, increased insect attack and death.

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7 WOMBATS

Stephen Jackson

Photo by Stephen Jackson

1. Introduction The family Vombatidae contains three species of wombats: the common wombat, southern hairy-nosed wombat and the northern hairy-nosed wombat. Wombats are large stocky, powerful marsupials that weigh up to 50 kg and are fossorial, ie they have extensive burrow systems. Unlike other marsupials their teeth grow continuously, like those of rodents, to cope with their diet of primarily coarse grasses that are highly abrasive. Common wombats and southern hairy-nosed wombats are still relatively common, though many are killed by cars or shot each year under permit. The northern hairy-nosed wombat remains one of the world’s most endangered species, with a population of approximately 80–115 individuals at Epping Forest in central Queensland, after once being much more widely spread (Strahan 1995; Taylor et al. in prep.). Despite being considered unattractive and sometimes truculent(Crandall 1964), common wombats have been held in numerous zoos throughout Australia and the world. Collins (1973) reported that they had been held in some 41 zoos up until 1969. The first common wombats to be held in a zoo were kept in the zoological gardens attached to the Natural History Museum in Paris in 1803. The wombats were returned to France by the expedition of Nicholas Baudin on the ship, the Naturaliste. One of the wombats was given to Baudin by the captain of an English schooner off the coast of New South Wales and Baudin collected another two from the population on King Island, which is now extinct (Skerratt et al. 1998). Home (1808) held another animal in Australia, which lived for two years in captivity and was fed vegetables and hay. London Zoo had common and hairy-nosed wombats well before 1863 (Gray). Common wombats in their collection lived for 26 years and the hairy-nosed wombats lived more than 17 years (Flower 1931). Today common wombats are held in many Australian zoos including Western Plains Zoo in Dubbo, Gosford Reptile Park, Healesville Sanctuary and several overseas zoos including Auckland Zoo. Southern hairy-nosed wombats are found in several Australian zoos including Adelaide Zoo, Currumbin Sanctuary, Melbourne Zoo, Perth Zoo, Taronga Zoo and Western Plains Zoo in Dubbo, with some 22 zoos known to have exhibited them by 1969 (Collins 1973; Lees and Johnson 2002; pers. obs.). Records at London Zoo indicate that southern hairy-nosed wombats have been held there since 1862 (Flower 1929, 1931). The northern hairy-nosed wombat is presently not held in any institution. The first known captive individual was a female animal known as ‘Joan’ that was held for 27 years by a farmer on a property adjacent to Epping Forest National Park where the remaining animals live, and which died in 1993. A second animal, an adult male, ‘Solstice’ was brought into captivity in June 1996 at Western Plains Zoo in Dubbo but died after approximately seven months (in January 1997) after having difficulty adjusting to captivity.

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2. Taxonomy 2.1. Nomenclature Wombats belong to the family Vombatidae. There are two genera and three extant species of wombats within this family (Table 1). The first species to be described was the common wombat (Shaw 1800), later the southern hairy-nosed wombat was described (Owen 1845). The northern hairy-nosed wombat was not described until 1872 by Richard Owen. Class: Mammalia Supercohort: Marsupialia Cohort: Australidelphia Order: Diprotodontia Suborder: Vombatiformes Superfamily: Vombatoidea Family: Vombatidae Genus Species: Lasiorhinus krefftii Northern hairy-nosed Wombat Lasiorhinus latifrons Southern hairy-nosed Wombat Vombatus ursinus Common Wombat Etymology Lasiorhinus – Hairy nose krefftii – After Gerrard Krefft who was a curator at the Australian Museum latifrons – Broad forehead. Refers to the wide nose Vombatus – Derived from Aboriginal names used for the wombat ursinus – Bear-like.

Table 1. Species of wombats and their conservation status. CR – critically endangered, LR – lower risk. Species

Weight (g)

Head and Body length (mm)

Status

Lasiorhinus krefftii

27–35

970–1110

CR

Lasiorhinus latifrons

19–38

772–934

LR

Vombatus ursinus

22–50

900–1150

LR

From Strahan (1995), Maxwell et al. (1996) and Taggart and Temple-Smith (unpub. data)

3. Natural history 3.1 Morphometrics Depending on the species, wild adult wombats range in body weight from 19 to 50 kg and are approximately 900–1150 mm in body length (Strahan 1995) (Table 1).

3.2 Distribution and habitat The common wombat is found in south-eastern Australia, mostly in temperate forests and grasslands, although they also occur above the snowline in mountainous areas during winter (Fig. 1). The northern hairy-nosed wombat is only found on one property in central Queensland at Epping Forest National Park where it occupies semi arid grasslands. The southern hairy-nosed wombat occurs in southern South Australia and south-eastern Western Australia as several disjunct populations in semi-arid grasslands (Fig. 1).

3.3 Conservation status

Synonyms can be found in Dawson (1988).

Both the common wombat and southern hairy-nosed wombat are considered common and of low risk of extinction apart from the South Australian populations of the common wombat that are regarded as vulnerable (Temby 1998). In contrast, the northern hairy-nosed wombat is one of the rarest mammals in the world. It is critically endangered, with a population size that has been as low as 40 individuals but presently has at least 80 individuals known to be alive with an estimated population of approximately 113 animals (Hoyle et al. 1995; Taylor et al. in prep).

2.4 Other common names

3.4 Diet in the wild

2.2 Subspecies The hairy-nosed wombats do not have any subspecies, however the common wombat has three subspecies, which include Vombatus ursinus ursinus from Flinders Island, Vombatus ursinus hirsutus from the mainland and Vombatus ursinus tasmaniensis from Tasmania (Strahan 1995).

2.3 Recent synonyms

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Wombats are grazing herbivores feeding on a variety of grasses, sedges, forbs, roots and bulbs, eating species which are largely proportional to their availability. Grasses most utilized by common wombats for food include tussock grass Poa sp., kangaroo grass Themeda australis, spear grass Stipa sp. and wallaby grass Danthonia penicillata with others such as oats Avena sativa, Australian salt grass Distichlis distichophylla,

Wombats

Northern hairy-nosed wombat

Southern hairy-nosed wombat

Common wombat

Figure 1. Present distribution of the common wombat, the northern hairy-nosed wombat and southern hairy-nosed wombat. Taken from Triggs (1996) with permission of UNSW Press.

perennial rye grass Lolium perenne, club rushes Scirpus sp., sedges Carex sp., mat-rushes Lomandra sp. also eaten at times (Mallett and Cooke 1986; Rishworth et al. 1995; Triggs 1996; Woolnough 1998). Due to the highly abrasive nature of the silica in the grasses that wombats eat, their teeth grow continuously. This feature is unique amongst the marsupials.

3.5 Longevity 3.5.1 Wild

1973), however there are records of them living to 26 years of age in London Zoo (Flower 1931). Similar to common wombats, southern hairy-nosed wombats typically live 10–15 years but life spans of 25 years have been recorded (Flower 1931; Melbourne Zoo). The only record of longevity of a captive northern hairy-nosed wombat is that of the female wombat ‘Joan’ which was caught as an adult and lived for some 27 years in captivity with a family who live next to Epping Forest National Park (Woolnough 1998).

In the wild southern hairy-nosed wombats have been known to live for 14–15 years (Wells 1989). Comparatively little is known of the longevity of common wombats in the wild, however it appears that they can live for more than 15 years (Table 2) (Triggs 1996).

3.5.3 Techniques to determine the age of adults Once wombats reach adult size, there is no reliable technique for aging them. Patterns of tooth wear are commonly used to age mammals, however this is not possible in wombats as all the teeth grow continuously.

Table 2. Longevity (years) of different genera of wombats in the wild and in captivity; the highest recorded longevity is in brackets.

4. Housing requirements

Genus

Wild

Captivity

References

Lasiorhinus

14–15

10–15(27)

1, 2, 3, 4

Vombatus

15

12–15(26)

1, 5, 6, 7, 8, 9

References: 1 Mitchell 1911; 2 Flower 1931; 3 Wells 1989; 4 Woolnough 1998; 5 Schmidt 1880; 6 Fleay 1957; 7 Crandall 1964; 8 Collins 1973; 9 Triggs 1996.

3.5.2 Captivity Common wombats typically live 12–15 years in captivity (eg Schmidt 1880; Fleay 1957; Crandall 1964; Collins

4.1 Exhibit design The exhibit structure for wombats needs to be of only a basic design as wombats are highly destructive due to their very powerful build and digging habits. They will pull up plants and dig under and around logs and other furnishings. The floor should be of soil with a mesh underlay or concrete layer approximately 1–1.5 m below the surface to prevent them from escaping under the fence. The walls should be smooth as they may chew or dig at mesh fences, which may result in holes in the fence

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and damage to the wombats’ teeth, gums and feet (Booth 1999). Although common and hairy-nosed wombats can live in environments where the temperature can reach 35–45°C with relative humidities of 2–5%, the corresponding temperature in the burrow is about 10–27°C with 60–70% humidity (Wells 1971; Shimmin et al. 2002). Wombats do not sweat, which is useful for conserving water but makes them very susceptible to heat stress. Common wombats can show signs of overheating when temperatures exceed 24°C (Brown 1964) and hairy-nosed wombats when it is 33–35°C, with deaths being known to occur in temperatures above 38°C (Ride 1970; Wells 1971; Gaughwin 1982; Williams 1990). Southern hairy-nosed wombats are known to salivate profusely when they get hot, resulting in all the fur around their lower jaw and upper chest getting wet (Taggart and Temple-Smith unpub. data). If captive animals are kept outdoors where they cannot construct burrows, appropriate measures must be taken so that they can behaviourally thermoregulate. Provision of a burrow or the means to construct one will help make them feel secure. Burrows can be constructed using mock rock caves, pipes or hollow tree trunks. Overstorey planting will provide shade and should be included. Sprinklers and adequate shading during warm weather should always be provided (Gaughwin 1982; pers. obs). Water can be provided via a water feature, a stainless steel bowl or an automatic filling device. Although the enclosures do not need to be totally covered in, the surrounding wall should be at least 1.2 m high (with a smooth wall) and continue below the surface to a depth of at least 1 m, or until it reaches the buried mesh so there are no points that can allow the wombats to escape, above or below the ground. Wombats have also been held successfully indoors, which has the advantage of allowing better control of the temperature. In these enclosures, soil, sand or leaf litter should still be provided over the concrete floor to allow natural digging. The indoor enclosure allows the use of reverse lighting to display them when they are generally most active (normally at night). Brookfield Zoo in Chicago, for example, has successfully used this technique to display southern hairy-nosed wombats (Crowcroft and Sonderlund 1977). Apart from concrete or brick walls, other materials have been used successfully, including pool fencing. Some fencing types are not recommended, these include corrugated iron, because of the reflective heat in summer and cyclone mesh below 3.15 mm diameter, because the wombats will chew through it (Williams 1990).

4.2 Holding area design The holding area design is of a very similar principle to the exhibit design and only needs to be quite basic. If held as pairs, provision should be made to minimize the effect of aggression.

4.3 Spatial requirements A pair of wombats requires at least 45 m2 as well as a shaded nesting area. Larger enclosures are preferable and enclosures up to 400 m2 have been suggested to reduce the likelihood of pacing, climbing and other attempts to dig out of the enclosure (Booth 1999). Although common wombats are usually not kept with more than two individuals together, southern hairy-nosed wombats have been readily held in groups. If held as groups, an additional area of at least 9 m2 should be provided for each additional animal.

4.4 Position of enclosures The enclosures should be situated in an area that has plenty of shade during hot weather and provides sunny areas during cooler weather, as wombats like to bask when it is cold.

4.5 Weather protection The enclosures can be open, semi enclosed or fully enclosed. If open they need to have adequate shade and sprinkler systems to allow the wombats to cool themselves in hot weather.

4.6 Temperature requirements Heating is not required, however dry clean nesting material such as straw or hay should always be available within the shelter.

4.7 Substrate The substrate should be soil, leaf litter or sand that is well drained so that flooding does not occur. Apart from allowing activity and other natural behaviours, the provision of substrates to allow digging enables the wombats to wear down their claws, which may otherwise grow too long. If provision is being made for wombats to excavate their own burrows, a sandy loam works well as wombats use this for burrowing in the wild (Steele and Temple-Smith 1998). The provision of sand or soil will also allow the wombats the opportunity to dust bathe (Triggs 1996). If only a cement floor is provided and they cannot dig, their nails may grow excessively (Williams 1990).

Wombats

4.8 Nest boxes Wombats need areas to retreat from the sun during hot weather. Nest boxes should be approximately 1 m × 1 m × 1 m with a hinged lid and lined with hay. They should be positioned in the shade wherever possible in outdoor enclosures. The entrance to the nest box should be about 30 cm high to allow the wombat to rub its back against the doorframe (Gaughwin 1982). Brick sleeping dens have been used at several institutions (Williams 1990).

4.9 Enclosure furnishings Few enclosure furnishings are required due to wombats’ destructive nature. Large hollow logs, branches, large rocks and terracotta pipes that are buried in the soil and large enough for them to sleep inside are useful. Attempts can be made to establish plants. Larger shrubs, trees and large tussocks have a better chance of survival than seedlings. To help plants establish, large rocks or logs can be placed around them to make them harder to dig up. If difficulties are encountered growing plants inside the enclosure, they may need to be planted around the exhibit to provide shading. Branches and rocks also allow the wombats to scratch. They will often use objects such as these in order to reach places on their body that they cannot easily reach with their claws.

5. General husbandry 5.1 Hygiene and cleaning All enclosures should be cleaned daily to remove faecal matter and uneaten food. Drinking water dishes should be cleaned and refilled daily. When all individuals permanently leave an enclosure, it should be scrubbed out if possible and thoroughly cleaned before the new animals are admitted.

5.2 Record keeping It is important to establish a system whereby the health, condition and reproductive status of captive wombats are routinely monitored. Records should be kept of: ■

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The collection of information on individual physical and behavioural patterns can contribute greatly to the husbandry of these species. It also allows the history of each individual to be transferred to other institutions if required and greatly facilitates a cooperative approach to data collection amongst institutions. In most of the larger institutions ARKS (for general information on births, transfers and deaths), SPARKS (breeding studbook for species) and MedARKS (veterinary information) are used. These systems have been developed by the International Species Information System (ISIS), which is part of the Conservation Breeding Specialist Group (CBSG) software. As these are standardized, there is a high degree of efficiency in transferring information between institutions.

5.3 Methods of identification 5.3.1 Passive Integrated Transponder (PIT) tags These are implanted between the scapulae and can be used on all wombats. It is an excellent method of identification but can be expensive if many animals are implanted. PIT tags are a permanent method of identification but care must be taken when they are implanted as they may track out along the injection site. This may be avoided by sealing the entry wound with tissue glue (Vetbond®) or similar fast setting adhesive. They generally require the animal to be caught to confirm identification with a PIT tag reader. Tags may also move around under the skin to different regions of the body and occasionally cause secondary complications such as carcinomas (Vogelnest et al. 1997). 5.3.2 Tattoos Tattooing has been used successfully on the inside of the ear (Johnson 1991) and the medial aspect of the hind leg (thigh)(Skerratt 2001). 5.3.3 Visual identification As most wombats show a fair degree of variation in pelage colour and scars from fighting, visual identification can often be used (Triggs 1996). 5.3.4 Ear tags Ear tags are not recommended as they may be pulled out. They have been used, including self-piercing, nylon disc swivel tags similar to those used for cattle, pigs and sheep. Although ear tags are sometimes lost and can become

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entangled, they are highly visible which has the advantage that animals don’t need to be caught up for identification (McIlroy 1976; Skerratt pers. comm.). To locate veins in order to avoid them when making a hole through the ear, shine a torch up against the ear.

6. Feeding requirements 6.1 Captive diet Ad Lib Water Daily diet (per animal) ad lib meadow hay ad lib oaten hay ad lib fresh grass is ideal but time consuming to collect 500 g carrots 1 eucalypt or wattle branch lucerne or maize can be given on alternate days Supplement None An alternative diet that has been used with success includes: Daily diet (per animal) 400 g pellet 50 g maize 50 g oats (crushed) 50 g wheat Taggart and Temple-Smith (unpub. data)

The change in high quality food availability prior to the breeding season in hairy-nosed wombats, and potentially common wombats, may be an important trigger in breeding in the wild. Therefore, the provision of a bland diet of primarily pellets and hay during most of the year and then a large quantity of fresh green grass from several months prior to the breeding season until the end of the breeding season may assist in triggering reproduction. Although artificial diets are largely used, as much grass as possible should be provided fresh daily to supplement the diet. Wombats have a tendency to become obese on high energy and protein diets so some institutions include a starve day once per week (Gaughwin 1982). However, a better strategy is to provide a low energy, low protein diet (Skerratt pers. comm.). Due to their low metabolic rate and slow digester passage rates wombats should be given a diet based primarily on grass and/or palatable but low quality food such as hay, ad lib (Booth 1994). High energy diets, such

as pasture replacement pellets, maize, fruit, vegetables and lucerne should not be given, or only occasionally, as these can lead to obesity and other health problems as they are too high in energy for long-term maintenance (Booth 1994; Skerratt pers. comm.). Wombats should also not be fed dry dog food as it is high in protein, low in fibre content and has a mineral balance designed for carnivores (Booth 1994). There may be a link between feeding inappropriate diets and systemic calcification seen occasionally in captive wombats (Booth 1994; Skerratt et al. 1997).

6.2 Supplements No specific supplements are needed, however additional food items such as branches of eucalypts and wattles can be added every few days since wombats occasionally eat bark (Triggs 1996). Take care not to provide diets high in copper, as a diet containing 36 ppm of copper (as CuSO4 in a pig grower supplement) appears to have resulted in fatalities in a captive southern hairy-nosed wombat (Barboza and Vanselow 1990).

6.3 Presentation of food Food is generally provided in stainless steel trays or hoppers 20 cm above the ground to stop the wombats defecating or walking on their food (Gaughwin 1982; pers. obs.). One tray is normally provided for each animal.

7. Handling and transport 7.1 Timing of capture and handling Wombats are usually best caught in captivity during the day when they are less active.

7.2 Catching bags Strong hessian bags or wooden boxes are generally used to transport wombats. When more control is needed, a tapering canvas bag with lace-up inspection ports is useful. If the bag is placed over its head, the wombat will readily climb in until it is firmly wedged (Wells 1971).

7.3 Capture and restraint techniques Juvenile wombats less than about 18 months of age are generally picked up easily under the armpits and carried this way. Adult wombats are large, powerful animals and can be highly aggressive (particularly common wombats). They will readily attack and bite legs, arms or hands and cause significant injury. Some animals will

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with the advantage that no one has to hold a struggling animal.

7.5 Release Wombats need to be released with care, as aggressive individuals can turn and try to bite. Therefore, release it and quickly get out of the exhibit. Ideally, particularly aggressive animals should be released over a small wall (approx 1 m high) so that it cannot bite. If this is not possible, it may be worthwhile to release the wombat while standing in a plastic or metal garbage bin and then retreating from the enclosure once the animal settles down.

7.6 Transport requirements

Figure 2. Restraint technique used to hold wombats.

retreat into the nest box, pipe or log and present their rear end towards you. In this case, great care needs to be taken if you are trying to retrieve the wombat as it may endeavour to crush your hand or arm against the side or roof of the hollow. The normal method is to grip one of its hind legs and pull the animal out of the box. Boxes with hinged lids are useful to gain access to wombats. Aggressive wombats that charge can often be tricked into charging into a hessian sack. If manual restraint is required, approach the animal from behind and hold it in position by placing a foot against its rump so it cannot reverse, and placing a hand on each shoulder so that it cannot turn or go forward. Firmly hold its shoulders in place with your hands and move back over the shoulders towards the armpits, sliding one arm under the armpit and across the chest. Pick up the animal, placing one arm under both front legs and support its rump with your other arm (Fig. 2). Highly aggressive individuals may put their head back and try to bite so keep your head tilted back and be wary of this. These animals can be sedated with an intramuscular injection of the drug combination tiletamine/zolazepam (Zoletil®) at 3 mg/kg to enable them to be easily handled for simple procedures such as venepuncture (L. Skerratt pers. comm.).

7.6.1 Box design Due to the very strong build of wombats, boxes must also be very strongly built, otherwise the wombat is likely to dig its way out during transit. Further specific details of the box design can be found in IATA (1999). 7.6.2 Furnishings None required. 7.6.3 Water and food Due to their low metabolic rate and long digestion times, wombats do not need to be fed for trips less than 24 hours (they can manage not feeding for considerably longer than this) (Taggart and Temple-Smith unpub. data). For longer journeys, food and water should be provided in a deep dish. Although, if the animals have just been removed from the wild they will not touch food or water (Taggart and Temple-Smith unpub. data). 7.6.4 Animals per box One animal per box. Females with pouch young should not be transferred unless the young are still attached to the teat.

7.4 Weighing and examination

7.6.5 Timing of transportation Due to the wombat’s inability to tolerate high temperatures, transportation should be overnight or in the morning in cooler weather. Avoid transporting animals in temperatures above 24°C (Skerratt pers. comm.).

Wombats can readily be weighed by holding them, weighing yourself with the wombat and then subtracting your body weight. They can also be placed in a heavy-duty hessian or canvas sack (in which they tend to sleep) and weighed on stand-on scales or spring balances,

7.6.6 Release from the box Generally, the box is opened and the wombat is able to exit in its own time. The box is then removed when the wombat has established another area as its nest site.

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8. Health requirements Edited by Dr Lee Skerratt

8.1 Daily health checks Each wombat should be observed daily for any signs of injury or illness. The most appropriate time to do this is generally when the enclosure is being cleaned in the morning or when food is being replaced as this is when the wombats are most likely to be active. During these times, each animal within the enclosure should be checked and the following assessed: ■ ■

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Coat condition Discharges – from the eyes, ears, nose, mouth or cloaca Appetite Faeces – number and consistency Changes in demeanour Injuries Presence and development of pouch young by observation of the bulge in the pouch.

8.2 Detailed physical examination 8.2.1 Chemical restraint Pre-anaesthetic fasting is not required for adult wombats as they are not prone to regurgitation (Vogelnest 1999). Hand-reared young should not be fed for at least one hour before anaesthesia. Sedation to allow handling can be undertaken using diazepam (Valium®) at 0.5–1.0 mg/ kg intramuscularly in the thigh muscle. Sedation is usually not required for transport (Vogelnest 1999). Anaesthesia can be produced using injectable agents such as tiletamine/zolazepam (Zoletil®) at 3–8 mg/kg intramuscularly in the triceps or quadriceps, with the lower doses being adequate for minor procedures, such as blood collection (Vogelnest 1999). Inhalation anaesthetic agents such as isoflurane or halothane in oxygen are frequently used for induction and/or maintenance anaesthesia, however isoflurane is preferred since there is greater relaxation of muscles. Intubation is difficult and not usually attempted or required. Rather, anaesthetic gases and oxygen are usually delivered by face mask (Vogelnest 1999). Endotracheal intubation is possible in wombats if a urinary catheter is used initially to enter the trachea and then an endotracheal tube is guided over the catheter into the trachea (L. Skerratt pers. comm.). 8.2.2 Physical examination The physical examination may include the following:

Body condition – Various body condition indices have been used to examine the condition of wombats. Two have been developed specifically for wombats. A subjective condition index provides a score of one to five (Horsup 1998): 1. Ribs visible, backbone and pelvis 2. Ribs covered but easily felt, backbone still visible, and the rump is sunken 3. Pelvis, backbone and ribs covered 4. Pelvis, backbone and ribs well covered 5. Wombat in excellent/fat condition However, all of these indices have a poor correlation with body fat (Woolnough et al. 1997). A highly accurate method of determining body condition has been developed for southern hairy-nosed wombats (and could be used for others). This uses bioimpedance analysis, which utilizes an electric current to predict the amount of body fat and total body water (Woolnough et al. 1997). ■

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Temperature – Normally 32–36.7°C. Can be taken through the anus via the cloaca (Gaughwin 1982; Triggs 1996; Booth 1999). Weight – Record and compare to previous weights. Trends in body weight give a good general indication of the animal’s state of health, provided age, sex and geographical origin are taken into account. Animals in captivity should be weighed monthly to gain an indication of trends. Pulse rate – Normally 40–45 beats per minute at rest and 55–60 when active. The systolic pulse rate of the femoral artery can readily be found (Gaughwin 1982). Respiratory rate – Normally 12–16 breaths per minute in deep sleep and 26–32 per minute whilst dozing (Wünschmann 1966; Triggs 1996; Booth 1999). Fur – Check for alopecia, ectoparasites, fungal infections or trauma Eyes ➝ Should be clear, bright and alert ➝ Normal bilateral pupillary light response ➝ Normal corneal reflex ➝ Should not have any discharges Also check for the presence of lumps over body and auscultation of lungs Cloaca ➝ Should be clean ➝ Check for faeces around the cloaca Pouch ➝ Condition of the pouch

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Check whether lactation is occurring by milking teats ➝ If pouch young are present record sex, stage of development, weight if detached from the teat and measure to determine age from growth curves if available Males ➝ Check testes – size (length, width, depth) and consistency (firm, not squishy) Note testes size does not change in or out of the breeding season ➝ Extrude penis and assess ➝ Accessory gland bulge (length and width), which is a good indicator of breeding. These are located either side of the cloaca (Taggart and Temple-Smith unpub. data). ➝

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8.3 Known health problems 8.3.1 Ectoparasites Cause – Mange can occur from infestations of the skin with the mite Sarcoptes scabiei burrows into the deeper parts of the stratum corneum (Martin et al. 1998; Skerratt et al. 1998). Sarcoptic mange occurs throughout the range of the common wombat and kills many individuals (Martin et al. 1998; Skerratt 1998; Skerratt et al. 1998). Sarcoptic mange occurs less commonly in southern hairy-nosed wombat populations (Skerratt 2001). Other mites that are known to occur on the skin of wombats include Acaroptes and Cytostethum spp., which are apparently harmless (Doube 1981; Booth 1999). The ear mite Raillietia australis found in the common wombat does not cause obvious problems (Skerratt 1998). Most wild common wombats have infestations of ticks including Ambylomma sp., Aponomma auruginans, Ixodes cornuatus, I. holocyclus, I. victoriensis and Ixodes tasmani (Roberts 1964, 1970; Green and Munday 1971; McIlroy 1973; Presidente 1982; Smales 1987; Skerratt 1998; Gerhardt et al. 2000; Skerratt 2001). Several genera of fleas are known to occur on wombats including Lycopsylla spp. and Echidnophaga spp., which have been collected from common wombats, southern hairy-nosed wombats and northern hairy-nosed wombats (Doube 1981; Gerhardt et al. 2000). Signs – Fur loss and the presence of thick scaly crusts (parakeratosis) on the body (Skerratt 1998; Skerratt et al. 1999). Severe pruritis (itching) and erythema (reddened skin) are also common (Skerratt 2001). In severe cases large open purulent sores may occur and may be fly

struck (Skerratt 1998). Movement, vision and mastication may be impaired by the severity of the skin changes and death through starvation or misadventure is likely to occur in wild animals (Booth 1999). Ticks occur more commonly on the ventral areas and on the ears (Skerratt 1998). Severe infestations can cause anaemia (Presidente 1982). Diagnosis – Visual observations or a skin scraping and microscope examination to identify the parasites. Identification of sarcoptic mange is made by taking skin scrapings or samples of the parakeratotic crust and confirming the presence of Sarcoptes scabiei mites or their ova (Fain 1968; Perry 1983; Skerratt et al. 1998). Treatment – In mild cases a topical acaricide may be effective, such as three or four treatments of 1.25% solution of amitraz (Demadex®, Delta Laboratories) at weekly intervals (Perry 1983). Systemically absorbed agents such as phosmet (Portect®, Smithkline Beecham) and ivermectin (Ivermec®, Merck and Co.) are effective but also need to be repeated every 10 days for a total of six treatments (Booth 1994; Rose 1999; Skerratt 2001). Parakeratotic crusts should be removed by soaking in keratolytic solutions (Booth 1999; Skerratt 2001). In advanced cases, euthanasia is the most humane approach (Booth 1994; Rose 1999). Wombats should be observed for at least one month after the last treatment for recurrence of clinical signs after temporary abatement to ensure that all mites have been eliminated (Skerratt 2001). Ticks and fleas can be treated with an insecticidal wash (Malawash®, ICI Australia), diluted as recommended for dogs and given 14 days apart (Presidente 1982). Ticks can also be removed manually. Prevention – Sarcoptic mange can be readily controlled by addressing the first signs of an infestation before they progress. It is also important to clean the enclosure and change bedding since Sarcoptes scabiei may survive off the host for two to three weeks under favourable conditions of low temperature (approx. 10°C) and high humidity (98%)(Arlian 1989). It is important to quarantine animals of unknown history prior to introducing them into the collection. Ticks and fleas can be managed by continual monitoring especially if the animals are in a natural habitat enclosure. Change the bedding regularly (L. Skerratt pers. comm.). 8.3.2 Endoparasitic worms Cause – Various species of cestode are known from common wombats, however three infect common wombats as metacestodes (immature tapeworms), two of

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which, Echinocooccus granulosus and Anoplotaenia dasyuri, occur rarely. Two species of cestode are recorded from hairy-nosed wombats. Several cestodes appear pathogenic as Progamotaenia festiva has been associated with mild cholangitis or fibrosis of the bile ducts and Taenia hydatigena, metacestode stage, with hepatic granulomata in common wombats (Presidente and Beveridge 1978; Smales 1998). Phascolotaenia comani has been commonly reported and Paramonezia johnstoni occasionally reported in common wombats (Smales 1987; Skerratt 1998). P. diaphana has been recorded in southern hairy-nosed wombats (Beveridge 1980). Several species of nematodes are known to coexist in the colon of most wild common wombats including Oesophagostomoides giltneri, O. longispicularis and Phascolostrongylus turleyi (Beveridge 1978; Smales 1994; Skerratt 1998). Larvae of Baylisascaris tasmaniensis have been identified in granulomatous lesions in several organs in common wombats in Tasmania (Munday and Gregory 1974). Oesophagostomoides stirtoni and Macropostrongyloides lasiorhini occur in southern hairy-nosed wombats and O. eppingensis in the northern hairy-nosed wombat (Beveridge 1978; Presidente 1982; Smales 1998). The lungworm Marsupostrongylus coulsoni occurs in the common wombat (Mawson 1955; Beveridge and Mawson 1978; Spratt 1979; Spratt et al. 1991). Strongyloides spearei almost invariably occurs in the small intestine of common wombats (Presidente 1982; Skerratt 1995; Skerratt 1998). No native trematodes have been found in wombats but the liver fluke Fasciola hepatica has been commonly found in wild common wombats in swampy areas or along creeks that are suitable for the intermediate host, which are snails of the genus Lymnea (Spratt and Presidente 1981; Smales 1998). Signs – Signs of cestode infection are not obvious unless metacestodes cause severe damage to internal organs such as the liver. Nematodes such as Strongyloides spearei have resulted in mild enteritis, Marsupostrongylus coulsoni is associated with mild interstitial pneumonia and strongylid nematodes that live in the colon cause a mild eosinophilic response within the intestinal mucosa (Skerratt 1998; Twaddell 1998). Trematodes can cause jaundice and ascites due to extensive hepatic fibrosis and marked fibrosis of the bile ducts (Spratt and Presidente 1981; Smales 1998). Diagnosis – Faecal flotation and the presence of eggs or proglottids (segments that make up the worms) (L. Skerratt pers. comm.). Only infection with adult cestodes can be diagnosed in this way since the metacestode stage of the cestode life cycle occurs within internal organs and

does not produce eggs or shed proglottids. The metacestode stage of Echinococcus granulosus produces hydatid cysts, which may be visible with radiography or ultrasound. Infection with the remaining metacestodes is made post mortem. Nematodes can be detected with faecal flotation and the Baermann technique to detect the presence of eggs and larvae in faeces. Adult parasites may be present in the liver on autopsy (D. Shultz pers. comm.; L. Skerratt pers. comm.). Treatment – Treated with anthelmintics such as Droncit® (praziquantel) (D. Shultz pers. comm.; L. Skerratt pers. comm.). Nematodes can be treated with anthelmintics such as ivermectin 0.2 mg/kg S/C twice at 10-day intervals can also be used. Trematodes can be treated with anthelmintics such as albendazole or triclabendazole at 10 mg/kg or closantel at 7 mg/kg. Prevention – Generally not required but could be with routine treatment with anthelmintics. It is also important to remove faeces from the enclosure (D. Shultz pers. comm.; L. Skerratt pers. comm.). High burdens of Strongyloides spearei in young animals have the potential to cause severe enteritis manifest as profuse diarrhoea and leading to death if not treated (Skerratt 1998; L. Skerratt pers. comm.). The best prevention for trematodes is to ensure the enclosure does not have any swampy areas, especially if these are adjacent to stock such as sheep (D. Shultz pers. comm.). Also, make sure the faeces are removed from the enclosure. 8.3.3 Protozoans Cause – Eimeria spp. may be associated with enteritis in sub-adult and hand-reared wombats (Barker et al. 1979; Hum et al. 1991; Rose 1999). The protozoan Toxoplasma gondii may infect hand-reared animals that have access to cat faeces in the house or yard since cats are the definitive host of Toxoplasma, although it can also kill wild wombats (Booth 1994; Skerratt et al. 1997; Skerratt 1998). Signs – May be associated with the onset of grazing in juvenile wombats, which occurs at approximately 10 months of age or sometimes earlier in hand-reared animals (Rose 1999; Hum et al. 1991). In severe cases, the wombat may develop mucoid to liquid green diarrhoea, progressively lose weight and become bloated (Rose 1999; Hum 1991). Although the Eimeria spp. that infect wombats are generally not considered to be pathogenic, deaths are known to occur in young animals (Hum et al. 1991). Toxoplasmosis can have neurological signs such as ataxia, circling and blindness or respiratory signs or both. Animals may have poor growth or lose weight. Death is

Wombats

often associated with interstitial pneumonia and/or focal encephalitis (Booth 1994; Skerratt et al. 1997; Booth 1999; Skerratt 1998). Diagnosis – Oocytes in faeces. Standard faecal flotation techniques are used for diagnosis (Rose 1999). Wet preparations of faecal samples can also be examined using a compound light microscope at a magnification of 400× (Rose 1999). Ante mortem diagnosis of toxoplasmosis is confirmed by serological testing to detect rising IgG Toxoplasma gondii titres. Direct Agglutination Test or Modified Agglutination Test using the commercial kit Antigene Toxo-AD and microtiter plate reagents (bioMerieux SA, Marcy l’Etoile, France) are useful (Skerratt et al. 1997; Bettiol et al. 2000; Miller et al. 2000). Treatment – Once clinical signs of enteritis have developed, treatment becomes very difficult as fluid therapy can be hard to deliver and anticoccidial therapies that are used in other species are often ineffective (Rose 1999). Clinical cases are usually treated with toltrazuril at 20 mg/kg PO once or 10 mg/kg PO SID over three days (Rose 1999). If treatment begins on toxoplasmosis as soon as clinical signs are apparent, it is possible to treat it successfully so do not wait until the diagnosis is confirmed as this may take several days (Booth 1994). Nonetheless, this disease is usually fatal in wombats (Booth 1999). Corticosteroids are not recommended (Booth 1994). Several drugs used to treat toxoplasmosis inhibit the folic acid biosynthetic pathway including dihydrofolate reductase inhibitors such as methotrexate, trimethoprim or pyrimethamine. Side effects, such as suppression of haematopoiesis, can be overcome by folinic acid therapy (Booth 1994). Alternatives include trimethoprim/sulphadiazine preparations at a dose rate of 5 mg/kg of the trimethoprim component BID/PO (Booth 1999). A further alternative involves a dose of pyrimethamine as a 0.5 mg/kg single dose combined with sulphadiazine at 60 mg/kg in three or four divided doses. Supplementation with folinic acid at a dose of 1 mg/kg/d is recommended. Continue treatment for at least two weeks after clinical signs subside (Booth 1999). Toxoplasmosis is prevented by avoiding all access to cats and cat faeces. Hay that may have been contaminated with cat faeces should be avoided (Dreeson and Lubroth 1983). Prevention – Coccivet® (80 g/l amprolium and 5.1 g/l ethopabate) may be used in the drinking water for the prevention of coccidiosis at a dose rate of 15 ml per 10 litres of drinking water (Rose 1999).

8.3.4 Bacteria Cause – Staphylococcus and streptococcus have been found in wild common wombats (Presidente 1982). Leptospira interrogans serovar hardjo has been found at a prevalence of 20% in wild wombats (Durfee and Presidente 1979). Secondary bacterial infection can follow fight wounds and be responsible for systemic infections. Most bacterial infections probably occur as a result of environmental stressors (D. Shultz pers. comm.). Other bacteria that have resulted in infections include Bacillus piliformis, Leptospira spp. and Salmonella spp. (Munday and Corbould 1973; Gaughwin 1982; Presidente 1982; Hum and Best 1988). Signs – Signs vary depending on the species and microbe site of infection. Staphylococcus and Streptococcus result in infected traumatic lesions of the footpads and nail beds of wild common wombats (Presidente 1982). In another case, the infection spread up the forelimb and spread through the lymphatic system to cause severe pneumonia (Presidente 1982). Other bacteria include Bacillus piliformis that results in Tyzzers disease (Hum and Best 1988), Leptospira spp. that cause leptospirosis (Munday and Corbould 1973; Presidente 1982) and Salmonella spp. (Gaughwin 1982). Diagnosis – Clinical signs and microbiological culture (D. Shultz pers. comm.). Treatment – Treated with topical chloramphenicol and weekly intramuscular injections of ampicillin (Presidente 1982). Prevention – Maintain high standards of hygiene and ensure that enclosures are well drained. Reducing stressors may also be important (D. Shultz pers. comm.). 8.3.5 Fungus Cause – Fungal lesions of Chrysosporium sp. have been found in the lungs of wombats in Tasmania and Victoria. Infection is common in wild southern hairy-nosed wombats and has been found in captive animals (Munday 1978; Gaughwin 1982; Skerratt 1998). Signs – Appears to be subclinical. Diagnosis – As incidental findings on autopsy. Treatment – Not required. Prevention – Not required.

9. Behaviour 9.1 Activity Common and northern hairy-nosed wombats are generally nocturnal and display little activity during daylight hours. They may spend up to 16 hours each day asleep in their burrows in order to conserve energy,

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which is a behaviour adapted to their low energy diet (Triggs 1996; Johnson 1998). Southern hairy-nosed wombats are known to bask and feed during the day in autumn, winter and spring (usually between 1400 hours and dark)(Taggart and Temple-Smith unpub. data). Wombats also need burrows due to their inability to regulate their body temperature when temperatures rise above 25°C, whereas they can easily withstand long exposures to air temperatures approaching 0°C for common wombats and 5°C for southern hairy-nosed wombats (Brown 1964; Triggs 1996; Taggart and Temple-Smith unpub. data). Burrows also enable wombats to conserve water by avoiding high and low ambient temperatures (which may vary from –5°C to 50°C) and low humidities (typically 2–5%) outside the burrows, compared with lower temperatures (10–27°C all year) and higher humidities (60–70%) in the tunnels (Wells 1971, 1978a; Shimmin et al. 2001). Therefore they emerge to feed at night when the conditions of temperature and humidity outside the burrow approach those inside (Wells 1989). In summer, wombats are more active from midnight to early morning (when the temperature is around dewpoint) before the temperature gets too hot, while in winter they are more active in late afternoon to early evening before temperatures have dropped (Wells 1978a; Taggart and Temple-Smith unpub. data). In more mild conditions, wombats typically emerge from the burrow after sunset when they graze for several hours. The only time in which wombats appear to be diurnal is when they sometimes bask in the sun during the cooler months, especially after cold nights (Wells 1978b; Woolnough 1998). They are also active above ground during cooler weather such as during winter, especially in snowy areas such as Kosciusko National Park (J. McIlroy pers. comm.). Observations on northern hairy-nosed wombats found no pattern between activity and temperature below approximately 26°C. However, above this temperature there was a direct relationship, with activity decreasing quickly until no activity above ground was observed at night when the temperature was approximately 32–34°C (Woolnough 1998). Other observations on the northern hairy-nosed wombat have found a highly significant relationship between temperature and activity, with activity increasing with temperature until 20°C, after which further increases in temperature result in a decrease in activity (Johnson 1991). Northern hairy-nosed wombats spend only two to six hours above ground with a significant relationship between the time of year (and hence temperature and food availability) and activity, with less activity in the

warmer months and more during the cooler months, especially in late winter and early spring (Johnson 1991). Wombats may spend time digging new or extending existing burrows which have tunnel lengths that range from only 1.5 m to more than 60 m. Each burrow has one or two entrances. Some wombats construct earth plugs to block the tunnel they occupied which may be a defensive behaviour (Steele and Temple-Smith 1998). Burrows of southern hairy-nosed wombats have a height of 30 cm and a width of 40 cm with terminal sleeping chambers, 80 cm long, 50 cm high and 60 cm wide, with the roof of the burrow 135 cm below the surface (Steele and Temple-Smith 1998).

9.2 Social behaviour Wombats are territorial with respect to feeding areas and may have disputes over the use of a burrow, which is the focus of wombat activity. In common wombats, individuals have up to 11 burrows over their home range, although most activity is confined to three or four burrows that can be used by more than one animal (McIlroy 1973, 1977; Wells 1989; Taylor 1993). The focus of social organization of the southern hairy-nosed wombat is the warren, which can have from one to 30 burrows of which many are interconnected (if there has been a collapse). There can be 10 or more wombats using them though not necessarily at the same time (Wells 1989; Steele and Temple-Smith 1998). Typically a wombat colony uses 10–20 warrens in a cluster, which can be spread over an area up to 1 km2 (Loffler and Margules 1980). Females show greater preference for burrows than males, but there appears to be no evidence of burrow ownership among warren occupants (Wells 1973, 1978b; Gaughwin 1982). Although in the wild adult male southern hairy-nosed wombats are dominant to adult females, there appears to be no set rule to dominance in captivity as in some cases the male is dominant and in others the female superior (Gaughwin 1982). If held in pairs or larger groups, careful observation needs to be made to ensure that subordinate animals do not suffer poor condition and possible death due to continual harassment (Gaughwin 1982). Fighting in both genera, although rare, consists of bites to the face, ears, rump and flanks (Wells 1989). Aggression is generally begun by a series of vocalizations that include a flat ‘chicker chicker’ and a rasping ‘chur’ that can be a prelude to chasing and fighting. This may involve biting the rump of the other animal (the roles can be reversed) with throaty snorts and nasal squeals being produced (Triggs 1996).

Wombats

9.3 Reproductive behaviour Courting occurs over two to three days in southern hairy-nosed wombats and begins with the male following the female after he has first inspected her cloaca or urine, often showing the flehmen behaviour (Gaughwin 1979). Flehmen also occurs in common wombats when they encounter the urine of females (Triggs 1996). It usually involves the male standing with his head stretching toward the female’s cloaca or urine with his mouth open while he retracts his upper lip, thus baring the gum and wrinkling the nose. It appears to be a mechanism to expose the vomeronasal organ to pheromones. When sniffing, the male moves his nostrils to and fro in an erratic fashion (Gaughwin 1979; Coulson and Croft 1981). This sometimes is associated with the male making rapid licking and mouthing movements during and after showing flehmen. This process appears to be part of how the male detects if the female is in oestrous and is therefore ready to mate. It has been suggested that one of the reasons for the poor breeding success of wombats in captivity is that most of them are hand-reared and thus have been denied the opportunity to acquire learned behaviours integral to courtship, normally gained through exposure to the dam while at heel, and during the sub adult development phase (Bryant 2000). In the wild, mating probably occurs in the burrow, as the male may have to prevent the female from escaping and also needs to be dominant to her. So, in captivity if the male is not dominant, successful copulation is unlikely to occur (Gaughwin 1982). Gaughwin (1982) suggested that most successful copulations in southern hairy-nosed wombats occurred in enclosures that simulated the natural burrow environment. A good indication of a successful mating is the presence of a plug of coagulated semen in the enclosure three to five days after southern hairy-nosed wombats have mated (Crowcroft and Soderlund 1977; Brooks et al. 1978; Taggart et al. 1998a). Courtship and mating behaviour in wild common wombats has been observed to involve the male chasing the female, which ran in circles or figures of eight in a 0.5 ha area (Marks 1998). The female only stopped if the male delivered a bite to her rump. In this case, mounting occurred outside, with both animals on their sides, which contrasts with the generally held belief that mating normally occurs in the burrow (Triggs 1996; Marks 1998). Further observations by Böer (1998) revealed five major phases to mating behaviour. These were: 1. The female followed the male, often matching his speed and making nose to nose contact with him

when they passed one another and presenting her urogenital region to the male by stretching her hind limbs. 2. One of the partners uttered several grunts that were answered by the other animal. This was repeated over two to three minutes. 3. A chasing phase, where the male chased the female which bounded away from him while he tried to bite her rump. This lasted for some 30 minutes. 4. The male approached from behind and tried to mate the female. After securing a grip he fell on his side and mated for approximately 30 minutes. 5. After mating both individuals rolled apart and fell asleep. Another observation of mating behaviour described how the male followed closely behind the female and put his forepaws on her back several times but she kept moving. He then caught her back leg in his mouth at which time she lay on her belly, resulting in the male lying on his side behind the female and mating her (Taylor 1993). Courtship and mating behaviour have not been observed in wild southern hairy-nosed wombats. However, the performance appears to be similar to that of common wombats based on captive observations (Marks 1998).

9.4 Bathing Although wombats are good swimmers, they usually do not bathe in water. However they will dust bathe in sand or dusty soil (Triggs 1996).

9.5 Behavioural problems Wombats are typically inactive animals but they will naturally dig a great deal. Stressed animals may vocalize frequently, show escape behaviour by continually trying to climb the walls and try and bite their way out of the enclosure.

9.6 Signs of stress Stress in wombats can be associated with very loud vocalizations (screams) and teeth gnashing. When being caught they may show a very aggressive defence, biting, scratching or attacking. Chronic stress can result in alopecia that is usually symmetrical and immunosuppression (especially in cases of severe mange) (Spielman 1994). The significance of stress and its potential to result in reproductive failure have been examined in common wombats. Captivity does not appear to suppress progesterone secretion and excretion during the oestrous cycle whether the animal is held by itself or with another animal. It was suggested that failure

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to mate might instead be due to a lack of behavioural stimulation (Bryant 2000).

9.7 Behavioural enrichment Although they do not require as much behavioural enrichment as other groups, several things can be done to provide behavioural enrichment to wombats. These include: ■ ■

■

Providing browse (see Section 6) Providing an adequate depth of soil to allow natural digging behaviours Planting tussock grasses to allow wombats to chew and dig them up

9.8 Introductions and removals Animals are usually easily removed from each other with few social problems when they return. If introducing animals as a pair, the male should be released first to the enclosure so that he can establish his territory before the female is introduced. If the male is introduced into an enclosure with an established female, the female may be dominant over the male and may not breed.

9.9 Intraspecific compatibility Most common wombats are held solitarily or as pairs, if compatible, which can be a male and female, two females or two juvenile males (less than 18 months of age). Southern hairy-nosed wombats can be held as solitary animals but preferably should be held as pairs or in small groups. Little is known of the northern hairy-nosed wombat’s behaviour in captivity but it is likely that they are best held as solitary animals or as pairs.

9.10 Interspecific compatibility

When southern hairy-nosed wombats are caught from the wild most do not eat for as long as four weeks. However, they can generally be encouraged to eat after two to three weeks if initially provided with fresh grass and left undisturbed. None of the animals in a case reported by Gaughwin (1982) became ill or died. In contrast, Wells (1971) experienced a mortality of 40% (thought to be due to starvation) in southern hairy-nosed wombats he caught, but the deaths could have been due to the initial condition of the animals. In some cases, animals brought in have been force-fed a mashed mixture of rolled oats, powdered milk, high protein cereal and glucose (Gaughwin 1982), though in the case of Wells (1971) doing this did not reduce the mortality rate. Animals that do not adapt to captivity should be returned to the wild and they should be kept in quarantine until their suitability to captivity has been assessed. Similar problems have been observed with the northern hairy-nosed wombat. The only animal brought into captivity in recent times was a juvenile male ‘Solstice’ that was trapped and sent to Western Plains Zoo in New South Wales in order to begin a captive breeding program. This animal refused to eat and had to be force-fed, which required it to be sedated and a syringe used to force food down its throat. He lost one-third of his body weight and died after seven months from a twisted bowel (Woodford 2001). The only other northern hairy-nosed wombat to be brought into captivity was a female called ‘Joan’ that was captured in 1966 when cattle farmers neighbouring Epping Forest bulldozed a burrow in search of a pet wombat. She was an adult when caught, approximately two years old, and survived until 1993 (Woodford 2001), although it is not known if she too found it difficult to adapt initially.

Because of their highly aggressive nature, wombats are not recommended to be housed with other species.

10. Breeding

9.11 Suitability to captivity

10.1 Mating system

Due to the historically poor breeding of wombats in captivity, most wombats in captivity are introduced through hand-rearing, as a result of the mother being killed on a road and they readily settle into captivity. Of non hand-reared wombats, juvenile common wombats (weighing 10–18 kg) appear to adjust to captivity better than adult animals (23 kg+)(Presidente 1982). Most eat fresh grass within two to five days after being captured and commercial food after seven to 14 days (Presidente 1982).

Outside the breeding season wombats are usually solitary with most animals being incompatible (eg Wünschmann 1966). However, common wombats may breed throughout the year depending on the environmental conditions (McIllroy 1973; Triggs 1996; Skerratt 2001). It has been proposed that in the three species of wombats the males are polygynous, whereas the females may be monogamous (Taggart et al. 1998b). However, recent evidence suggests that female common wombats are also polygynous (L. Skerratt pers. comm.). At Murrindindi in

Wombats

Victoria, females were found to have mated with different males in successive years (S. Banks unpub. obs.). There appears to be an age-graded ranking system determining access of males to fertile females (Stenke 1995). Larger males, weighing approximately 30 kg, sired most of the young at Murrindindi in 1999 and 2000 (S. Banks unpub. obs.).

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10.2 Ease of breeding Common and hairy-nosed wombats have not bred routinely in captivity. The major reason for the lack of successful breeding in captivity may be the ready availability of wombats that have been hand-reared after their mothers have been killed by cars, which are generally housed solitarily. The few records of breeding include common wombats being born at Halle Zoo in Germany in 1914 (Mohr 1942), Whipsnade Zoo in 1931 (Zuckerman 1953), Healesville Sanctuary (Condor 1970), Hannover Zoo (Böer 1998) and Western Plains Zoo in Dubbo New South Wales (C. MacCallum pers. comm.). Southern hairy-nosed wombats have bred at Perth Zoo in 1968 (Collins 1973), Melbourne Zoo in 1981 and 1998 (Anon 1982; pers. obs.), Taronga Zoo in 1981 (Anon 1982) and Brookfield Zoo (Crowcroft and Soderlund 1977). Individuals, both males and females, do not show mating behaviour, especially within the first three years until they appear to reach sexual maturity (Gaughwin 1982) and even after successful mating the female may not produce young (Crowcroft and Soderlund 1977; Gaughwin 1982). Due to the critically endangered status of the northern hairy-nosed wombat, only several specimens have ever been held in captivity, so there has not been the opportunity to breed them in captivity to date.

10.3 Reproductive condition 10.3.1 Females Wombats are generally placed in several categories depending on their reproductive status. For females these include: ■

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Non-parous (females that have never bred) – pouch shallow with no skin folds, clean and dry, teats very small. Parous (females that have bred previously but not presently) – pouch is deep but dry and dirty, the teats are slightly elongated. Oestrus – Clitoral swelling present (fleshy/pink) at the time of behavioural oestrus (Taggart and Temple-Smith unpub. data).

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Pregnant – Pouch bright red in colour, deep and very moist, skin folds may be observed on the lateral margins. Pouch young present – Pouch deep, very moist and young attached to the teat. Lactating (young absent from the pouch but still suckling) – Pouch area large, teats enlarged and mammary gland skin folds flaccid, hair sparse and stained, skin smooth and dark pink. Post lactation – Teats are still large, expressing only clear liquid and regressing in size.

If pouch young are present, there are a number of developmental stages and measurements that can be recorded and compared to existing growth curves (see Section 10.16), or used to establish curves for future reference. These include: Developmental stages ■ Sex distinguishable ■ Tips of ears free ■ Papillae of facial vibrissae evident ■ Eyelashes visible ■ Eyes open ■ Fur visible – slight tinge, medium or well developed ■ Tips of first incisors through the gums ■ At foot ■ Eating solids ■ Self feeding ■ Independent. Measurements (see Appendix 5) ■ Weight (g) – if not on teat ■ Head length (mm) – from the occiput to snout tip ■ Pes length (mm) – from the heel to the distal end of the longest toe, not including the nail ■ Head width (mm) – maximum width across the zygomatic arches ■ Tibia length (mm) – from the stifle to the heel. 10.3.2 Males The reproductive condition of males is not easily defined once they have obtained adult body size. The testis must be firm with the epididymis distinct.

10.4 Techniques used to control breeding As wombats have historically not bred well in captivity, the potential of breeding in excess to requirements is not an issue.

10.5 Occurrence of hybrids None are known to occur.

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Table 3. Wombats – reproduction and development. Permanent Pouch Exit (days)

Weaning (days)

Sexual Maturity (months) (F)

Sexual Maturity (months) (M)

Birth Season

Ref

Lasiorhinus krefftii

300–330

–

–

–

–

1


180–270

400

36

–

Nov–Jan

2, 3, 4

Vombatus ursinus

>150

400

24

–

All year

5, 6

1 Johnson and Gordon 1995; 2 Crowcroft and Sunderland 1977; 3 Gaughwin and Wells 1978; 4 Wells 1995; 5 Tyndale-Biscoe and Renfree 1987; 6 McIlroy 1995.

10.6 Timing of breeding

10.7 Age at first and last breeding

The common wombat appears to time breeding with both latitude and elevation so that the maximum growth rate of young corresponds with the maximum potential growth period of temperate grasses. This usually occurs in spring between September and January in south-eastern Australia, however births can occur throughout the year (Mallett and Cooke 1986; Green and Rainbird 1987; Wells 1989). As wombats are polyoestrous, they appear to be able to breed throughout the year in areas of high forage quality and abundance (Peters and Rose 1979; Green and Rainbird 1987). The timing of breeding is different in different locations with breeding December to March in the highlands of New South Wales and eastern Victoria (McIlroy 1973; Skerratt 2001) and from March to July in northern Victoria with most births in June and July (Nicholson 1963; Presidente 1982). The southern hairy-nosed wombat has a defined breeding season, with most births from late July to September and some in October and November, which correlates with the growth and germination of native pasture (late September to December) (Wells et al. 1986; Wells 1995; Taggart and Temple-Smith unpub. data). Weaning occurs in spring or early summer, or almost six months out of phase with the common wombat as these growth periods are associated with the winter rainfall patterns of the arid and semi-arid zones of South Australia (Wells 1989). When there is little rain, body weight and reproductive activity are decreased in both males and females (Gaughwin et al. 1998). Observations on the northern hairy-nosed wombat show a similar result, with a significant relationship between breeding rate of females and amount of summer rainfall. This suggests a nutritional constraint on breeding, although the mechanism is not clear given that the breeding cycle of most females commences before the onset of the summer rainy season (Crossman et al. 1994; Woolnough 2000).

Southern hairy-nosed wombats do not begin showing reproductive behaviour until at least three years of age (Gaughwin 1982). Common wombats breed when they weigh about 22 kg, which is equivalent to about three years of age (McIlroy 1973).

10.8 Ability to breed every year Common wombats appear to breed annually, however the two species of hairy-nosed wombats appear to coincide breeding with rainfall so that in years of low rainfall, they often do not breed. Northern hairy-nosed wombats breed on average twice per three years (Johnson and Gordon 1995).

10.9 Ability to breed more than once per year All species of wombats can breed only once per year due to the length of time required to raise the young, as there may be significant weight loss associated with lactation that prevents the female immediately breeding again (Skerratt 2001). Southern hairy-nosed wombats are able to return to oestrus if a young is lost early in the breeding season, however if it is lost from October to December the female does not re-enter oestrus (Taggart and Temple-Smith unpub. data).

10.10 Nesting requirements Female wombats should be provided with a well-built nest box, large hollow log, artificial burrow or, ideally, an area of earth in which they can dig their own burrow. Nesting material such as straw or hay should also be provided.

10.11 Breeding diet Births in hairy-nosed wombats appear to be correlated with rains and associated grass growth after rain when forage quality is maximal (Wells et al. 1986; Wells 1989; Woolnough 2000) so the provision of large amounts of fresh grass prior to the beginning of the breeding season

Wombats

25000

V. ursinus L. latifrons

Weight (g)

20000

15000

10000

5000

0 0

100

200

300

400

500

600

700

800

Age (days) Figure 3. Growth in body weight of the common and southern hairy-nosed wombats. Derived from Gaughwin (1982), Triggs (1996), Austin (1997) and Woods (1999). Standard deviation error bars are shown on the common wombat curve.

is recommended for these species. It has been suggested that the seasonal variability in the food resource and timing of the reproductive cycle allows the female to invest in fat in order to meet the higher energy demands of reproduction and lactation (Woolnough 2000).

10.12 Oestrous cycle and gestation period Common wombats are polyoestrous and have an oestrous cycle of 32–34 days, with oestrous lasting 24–81 hours (Peters and Rose 1979; Böer 1998). The gestation period is short, about 21 days (Wells 1989). The southern hairy-nosed wombat is monovular and has a gestation period of 20–21 days (Crowcroft and Sunderland 1977).

10.13 Litter size Usually only one young is produced for the three species, however there are records of two being successfully raised (Ride 1970; C. MacCallum pers. comm. – Western Plains Zoo, Dubbo NSW). Once the young are born the other wombats in the enclosure should ideally be removed to prevent the relatively high rate of losses experienced (Gaughwin 1982).

10.14 Age at weaning The young begin leaving the pouch and eating solid foods at about nine months of age and more than double their weight in the next three to eight months. They reach adult body weight at two years of age at which time they generally disperse (Wells 1989). The time in the pouch varies with species and ranges from 10–11 months in the

northern hairy-nosed wombat (Johnson and Gordon 1995) to seven to nine months in the southern hairy-nosed and common wombats (Table 3) (McIlroy 1995; Wells 1995). Weaning occurs in the common wombat at approximately 12–15 months of age when females are about 8.65 kg and males, 8.38 kg. Weaning occurs over about 50 days during which weight losses between 25 and 420 g are observed (Triggs 1996; Böer 1998). A male common wombat was observed taking solid food when he was about 8.5 months of age and 1330 g while still in the pouch, whereas two females have been first observed to eat solids at 1620 g and 1510 g when they were nine months of age (Böer 1998). This indicates that young wombats feed on a mixture of milk and solids for about three to six months (Böer 1998).

10.15 Age of removal from parents The young should be removed when it is about 20–28 months old, several months before the female comes into her next oestrus, as she can become increasingly aggressive towards the young (Böer 1998). Severe biting and chasing can occur at this stage causing the young to run back and forth in the enclosure or hide and cower in a corner (Böer 1998).

10.16 Growth and development The growth and development of common and southern hairy-nosed wombats is shown in Figure 3. Additional growth and development information references can be found in Table 4 and Bach (1998).

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Table 4. Growth curve measurements that have been developed for different species of wombats. WT – weight, HE – head length, LE – leg length, TO – total length. Common Name

Measurements

Reference


WT, TO, LE

1, 2, 3

Vombatus ursinus

WT, TO, HE

3, 4, 5, 6, 7, 8

1 Crowcroft and Soderlund 1977; 2 Gaughwin 1982; 3 Woods 1999; 4 Young 1980, 5 Presidente 1982; 6 Triggs 1996; 7 Austin 1997; 8 Böer 1998.

11. Artificial rearing 11.1 Housing As with all native mammals that have been taken into care, minimizing stress is a major consideration. Choosing suitable housing can help to create a stress-free environment. To achieve this, several factors should be considered including: ■ ■ ■ ■ ■

or brewer’s thermometer works well for checking the temperature of the pouch (George et al. 1995).

11.3 Diet and feeding routine 11.3.1 Natural milk Wombat milk increases in total solids during lactation from 22% in early lactation to 55% in late lactation, while lipids increase from 6 to 28% and proteins from 4% to 9% (Green 1984). In contrast, the concentration of carbohydrates decreases from 12% in early lactation to only 4% in late lactation (Table 5) (Green 1984). 11.3.2 Milk formulas The three main low-lactose formulas used for hand-rearing wombats are: ■

Securing the area from children and animals Maintaining the area in a hygienic manner Escape-proofing the area Clearing the area of obstacles and hazards Ensuring the area offers shelter from the weather and noise.

Hairy-nosed wombats (eg Osborn 1975; Christian 1977; Crowcroft and Soderlund 1977) and particularly common wombats (Presidente 1982; pers. obs.) are frequently hand-reared. Unfurred or finely furred young that weigh less than two kilograms should be placed in a soft cotton bag that is then placed in a well-insulated natural fibred pouch such as a woollen jumper or old windcheater. A box or laundry basket lined with clothing, blankets and an inner cotton-lined bag can be used (Austin 1997; George et al. 1995). Do not use synthetic fibres as these are either too hot or too cold and rub on the joey’s skin, producing pressure areas (George et al. 1995).

11.2 Temperature requirements The juvenile should be held in the temperature range of about 25–30°C (George et al. 1995; Austin 1997). Usually smaller wombats weighing less than 600 g should not be heated greater than 28°C (George et al. 1995). Use a minimum/maximum temperature gauge with a plastic-coated probe that can be placed next to the joey, as this will ensure that the temperature can be monitored (J. Cowey pers. comm.). A hot-water bottle (that is reheated every four hours) can be used for heating, but should be well wrapped inside towels or other fabric and should not be placed too close to the wombat or overheating or dehydration may occur. A Vacola bottling

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Biolac, which has three formulations – M100 with 2–5 ml of canola oil per 100 ml for furless joeys; M150, a transitional milk to use when dense fur has developed; and M200, which is used when the animal produces solid dark pellet droppings, as it contains elevated lipid in the form of canola oil. When the joey is nearing weaning, 2–5 ml of canola oil is added per 100 ml of formula. Mixing the formulas is the way to make the transition from one formula to another. The young animal should be fed 10–15% of its body weight per day. Di-Vetelact – Is a widely used, low lactose milk formula. Due to its low energy concentration when prepared as directed, some groups advise the addition of mono and polyunsaturated fats such as canola oil as with Wombaroo diets (Smith no date). Adding saturated fats in the form of cream has been suggested but it is too highly saturated and can lead to the malabsorption of calcium (Smith no date). Di-Vetelact should be fed at approximately 20% body weight, except in the case of very small joeys (less than 100 g). Wombaroo Wombat Milk – Charts are provided to assist in determining the type and volume to be fed. The three formulas range from 0.6 formula for joeys with greater than 60% of their pouch life completed, that have short dense fur and spend a lot of time out of the pouch. Evidence suggests that, if given the option, Wombaroo wombat formula gives better growth rate and hair quality than other milk formulas (Booth 1999).

Wombats

Table 5. Concentrations of major constituents of common wombat milk. Total Solids (%)

Carbohydrates (%)

Lipids (%)

Protein (%)

Calcium (mg/l)

Iron (mg/l)

22.0–51.0

4.0–12.0

6.0–28.0

4.0–9.0

4200

22

From Green (1984)

Folivorous species need to establish gut flora to break down the vegetable matter in the diet. This can be achieved by several methods including offering dry dirt (pica), which they may eat. It can also be assisted by adding half a teaspoon of natural yoghurt to the formula daily (Austin 1997). An alternative method to inoculate with bacteria is by choosing several fresh droppings from a healthy adult wombat, preferably of the same species, grinding them up, adding warm water, straining and adding 5 ml or one teaspoon to the joey’s bottle containing milk and mixing it up or giving it directly into the mouth by squirting it in (Austin 1997). When six months of age, Farex or Heinz Rice Cereal can be added to the Di-Vetelact formula by adding half to one teaspoon to every 200 ml and letting this stand for a few minutes before feeding (Austin 1997). 11.3.3 Feeding apparatus Very small joeys can be fed using a syringe fitted with a bicycle tyre valve rubber, plastic intravenous catheter or 1-inch length of infant gastric feeding tube (Bellamy 1992). Most wombat joeys will, however, be large enough to be fed with a plastic feeder bottle (50 or 100 ml) and a special wombat Type (a) teat (Austin 1997). The teat should be punctured with a hot needle (A. Gifford pers. comm.). 11.3.4 Feeding routine During the first few days in captivity, the wombat should be wrapped in a towel and the rearer should place a hand over the juvenile’s eyes whilst it is being fed (Austin 1997). The milk should be warmed to approximately 36°C before feeding. Young wombats should be fed approximately 15% of their body weight daily, although the demand decreases with the introduction of solid food (Booth 1999). Furless joeys should be fed every two hours and well-furred joeys should be fed every four hours (Booth 1999). Take care that the milk is not forced at a greater rate than it is sucked, as it can accumulate in the pharynx and be sneezed or coughed out the nostrils, or passed into the lungs where it can result in aspiration pneumonia and death (Presidente 1982). Replacing the teat and using a smaller hole in the teat can slow the rate of milk consumption and decrease the incidence of milk aspiration. Some rearers reduce the milk flow by adding

infant baby cereal so that the milk has the consistency of porridge (George et al. 1995). Once the young is fully furred and weighs approximately two kilograms, solid foods can be introduced. These can consist of cereals such as rolled oats, toasted wheat and then muesli with dog chow, crushed maize, grated carrot, apple and cut grass (Presidente 1982). Muesli has been known to get caught between the teeth, which can cause dental problems (J. Cowey pers. comm.). The number of daily feeds changes as the joey develops (Bellamy 1992). Very young, unfurred joeys should be fed every two to three hours around the clock. When furred, the number of feeds is reduced to five and the volume increased per feed. At full emergence the number of feeds is reduced to two or three per day and they should be given access to grass, grated apple, lucerne hay, wallaby pellets and vegetables (initially fed blanched) such as carrot, pumpkin and sweet potato (J. Cowey pers. comm.; pers. obs.). Joeys should be offered fresh water in a sturdy container as they can dehydrate, especially during warm weather. Water is especially important once the joey begins to vacate the pouch and eat solids (George et al. 1995).

11.4 Specific requirements The skin of unfurred and slightly furred young should be kept moist with the use of Sorbelene cream (not with added glycerine) to prevent it becoming dry and cracked (George et al. 1995). Baby oil does not appear to be properly absorbed and tends to stay on the skin surface where it rubs off and is absorbed by the liner bag fabric (George et al. 1995). When first brought in for hand-rearing, the joey may be dehydrated. If so, it can be given plain boiled water, which has been allowed to cool to 36°C, or 1 g of electrolyte replacer if available (Austin 1997). Vytrate can also be used at a ratio of 20 ml Vytrate to 250 ml water (J. Cowey pers. comm.). Take the joey to a veterinarian for examination. It is important to warm the joey prior to feeding to avoid the risk of inhalation pneumonia. If this takes too long, give fluids subcutaneously and bottle-feed later. If the joey is really cold, place it in a warm water

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bath and dry it off rather than putting it in a hot box (J. Cowey pers. comm.). Stress is a major problem in the successful rearing of native mammals and can be fatal. Therefore, it is important to keep noise to a minimum, not to overhandle the animal and to maintain high standards of hygiene (A. Gifford pers. comm.).

11.5 Data recording When an animal is first brought in for hand-rearing, its sex and approximate age, using growth charts, should be recorded. During the hand-rearing process a number of important pieces of information should be recorded. This information serves several purposes, including providing important background information such as food consumption which will assist a veterinarian reach a diagnosis if the animal becomes sick or fails to grow or gain weight. It also allows a comparison with growth curves to assess progress (Section 10.16) and to allow new growth curves to be established for measurements in which they presently do not occur. The following information should be recorded on a daily basis: ■ ■ ■ ■ ■

■ ■ ■



11.6 Identification methods Generally not required but can be given a PIT tag (see Section 5.3.1) once furred.

11.7 Hygiene Maintaining a high standard of hygiene is critical to the survival of the wombat joey. Emphasis needs to be placed on the following: ■

Maintain a clean pouch lining at all times. Older joeys can be trained to urinate on newspaper by keeping a piece of newspaper with the smell of urine on it.

■

■ ■

■

■

■

■ ■

■

■

Maintain personal hygiene by washing and disinfecting hands before and after handling the joey. Use antibacterial solution for washing hands with furless joeys, as their immune system is not well developed. Wash hands between feeding different joeys. Use boiled water when making up formulas for very young joeys. Clean spilt milk formula, faeces and urine from the joey’s skin and fur as soon as possible, and then dry the animal. Wash all feeding equipment in warm soapy water and sterilize it in a suitable antibacterial solution such as Halasept or Milton, or boil it for 10 minutes. Once sterilized, the equipment should be rinsed in cold water. Many carers store the teats and bottles in the fridge after they have been disinfected (J. Cowey pers. comm.). Only heat up milk once and discard leftovers. Avoid contact with other animals unless you are sure they pose no health risk. Some carers recommend that joeys, once fully emerged from the pouch, be allowed to socialize with other joeys to avoid human imprinting and encourage normal social behaviour (L. Skerratt pers. comm.). Stimulate to toilet before or after feeding. As with other marsupials, toileting can be done by the application of warm water to the cloaca using cotton wool to stimulate urination and defecation, which allows the animal to keep drier and warmer in its pouch. If furless, cover the joey’s body with Sorbelene cream after each feed until fur appears.

Good hygiene is important, so all excess milk or waste products should be cleaned away whenever possible, so the wombat remains warm and dry. As with other marsupials, toileting can be done after feeding by the application of warm water to the cloaca using a cloth. This induces urination and defecation, which allows the animal to keep drier and warmer in its pouch. This practice should be phased out once the animal urinates and defecates regularly without stimulation (Booth 1999).Use a new pouch liner after each feed.

11.8 Behavioural considerations Once a wombat reaches approximately 18 months of age, it naturally becomes increasingly independent of its rearer and generally becomes quite aggressive. Aggression is a normal behaviour, even in joeys, soon

Wombats

after emergence from the pouch. Mother wombats appear to be quite tolerant of this behaviour but a joey bite can be very painful. Prior to release they should be completely weaned from human affection, fed a diet of natural grasses and held with other wombats so they can develop their social skills.

11.9 Use of foster species Fostering within wombat species has been conducted successfully, with 100% success rates being observed in southern hairy-nosed wombats, provided the pouch young is transferred to another female with a young of equivalent or greater size. Young as small as 1.5 g have been transferred successfully to foster mothers using this process and the growth rates are unaffected (Taggart and Temple-Smith unpub. data). No interspecies fostering is known to have been used to date and the poor breeding success of wombats in captivity means that fostering between wombat species is presently unable to be used.

11.10 Weaning The wombat can be introduced to solid foods by providing freshly cut grass and ‘wombat pellets’ (Ridley Agriproducts) with weaning usually occurring by 14–15 months of age (12–19 kg for a common wombat), and sometimes as early as 12 months (approximately 11 kg) (Austin 1997; Booth 1999). The smallest southern hairy-nosed wombat caught above ground was approximately 6 kg in weight, with young remaining in the burrow after leaving the pouch until they reach this size (Taggart and Temple-Smith unpub. data). Fresh clover, leaves from cabbages or other members of the cabbage family should not be fed as these can cause gut problems and are known to kill young wombats (George et al. 1995). The number of daily bottle feeds can be reduced from four to three over several weeks, but

keeping the same volume of milk, and providing small pieces of solid food. After several more weeks when the wombat is at two feeds per day, the amount of formula can be decreased, without watering it down, until the animal is fully weaned after several weeks. A general rule is to decrease the formula by 5% per week as long as the joey continues to gain weight at a minimum of 5–10% of body weight per day (J. Cowey pers. comm.). Make sure that before fully weaning the wombat it is drinking plenty of water and eating lots of solids (Austin 1997). Weaning should be completed by 17–18 months of age. Often wombats wean themselves and refuse to drink any formula, but make sure this does not occur at less than 12 months of age (Austin 1997). At weaning, fresh water should be supplied at all times.

11.11 Rehabilitation and release procedures Preparation for release should begin once the wombat begins to leave the pouch (George et al. 1995). It should gradually be weaned from the foster carer into an enclosure with adequate soil depth that allows it to burrow and it should be fed an increasing amount of grasses. By 18 months of age, the young wombat is usually driven away by the mother. Ideally the wombat should be soft released where it can come and go from the carer’s home to the wild and then disperse permanently when it is ready. Wombats released as pairs appear to do better than those released on their own, though this bond quickly breaks down after release (George et al. 1995).

12. Acknowledgments Sincere thanks to Dr David Shultz, Dr Lee Skerratt and Dr John McIlroy for all their valuable comments. Grateful thanks also to Dr Lee Skerratt for providing a number of very useful references.

203


8 POSSUMS AND GLIDERS

Stephen Jackson

Photo by Stephen Jackson

1. Introduction The possums and gliders are a highly diverse group of marsupials, comprising six families, 20 genera and 58 species. They occur throughout Australia, New Guinea and numerous islands east of the Wallace Line, and range in size from only 6 g for the little pygmy-possum to over 10 kg for the bear cuscus that is found on Sulawesi. This group of mammals fills numerous niches, similar to those of rodents and primates elsewhere in the world, with some being folivores while others consume nectar, pollen and insects. Amongst the 27 Australian species there are several that are considered endangered, including the mountain pygmy-possum, Leadbeater’s possum and the mahogany glider, while several other species are considered vulnerable. Due to their diverse dietary niches, lifestyles, body size, and threatened status they can make good displays and captive management can assist in the conservation of several of the threatened species. Possums and gliders have long been held in captivity with records suggesting that considerable numbers of sugar gliders were held as pets as early as the 1830–1840s (Gunn 1851). Numerous zoos throughout the world have held possums and gliders including London Zoo, which had feathertail gliders in 1840, common brushtail possums since at least 1857, sugar gliders since 1865 and squirrel gliders in 1895 (Collins 1973; Flower 1931; Zuckerman 1953). New York Zoo had feathertail gliders in 1920, and this species has subsequently been kept at Taronga Zoo and Healesville Sanctuary for many years (Crandall 1964; pers. obs.). Healesville Sanctuary first held spotted cuscus in 1949 (Fleay 1949) and presently holds species including Leadbeater’s possum, sugar gliders, squirrel gliders, yellow-bellied gliders, ringtail possums, mountain brushtail possums and eastern pygmy-possums. Taronga Zoo holds species such as squirrel gliders, yellow-bellied gliders, Leadbeater’s possums, mountain pygmy-possums and ground cuscus (pers. obs.). Sugar gliders are kept in large numbers as pets in the United States of America and Canada and increasingly in Europe. Other rare species such as striped possums are held in zoos in the United States and Japan. London Zoo holds the striped possum from animals collected in New Guinea. Further details of the history of possums and gliders in captivity can be found in Collins (1973) and George (1990), while Lees and Johnson (2002) note the major Australian zoos that presently hold them.

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2. Taxonomy 2.1 Nomenclature Within the Suborder Phalangerida there are six families containing a total of 58 species of which 22 occur only in Australia, 31 occur only in New Guinea and surrounding islands and five occur in both regions (Flannery 1995a, 1995b; Strahan 1995). Australian Possums and Gliders Class: Mammalia Supercohort: Marsupialia Cohort: Australidelphia Order: Diprotodontia Suborder: Phalangerida Superfamily: Burramyoidea Family: Burramyidae Genus Species: five species in two genera (see Table 1). Superfamily: Petauroidea Family: Petauridae Genus Species: six species in three genera (see Table 1). Family: Pseudocheiridae Genus Species: eight species in six genera (see Table 1).

2.4 Other common names See Strahan (1995).

3. Natural history 3.1 Morphometrics The possums and gliders show a very large range in body size from 6 g for the little pygmy-possum to 10 kg for the bear cuscus. The morphometrics for the Australian species can be found in Strahan (1995).

3.2 Distribution and habitat Possums and gliders are well known across a wide range and many different habitats in Australia, including the arid regions of central Australia, throughout the east coast, northern Australia, Western Australia and Tasmania. Different species occupy a range of habitat types from open and closed woodland, rainforest and even alpine areas (Strahan 1995).

3.3 Conservation status The mountain pygmy-possum, Leadbeater’s possum and mahogany glider are endangered, while the western ringtail possum is vulnerable (Table 1). The rest of the Australian species of possums and gliders are considered at low risk of becoming extinct, though several are considered close to being threatened (Table 1).

3.4 Diet in the wild Superfamily: Tarsipedoidea Family: Tarsipedidae Genus Species: one species (see Table 1). Family: Acrobatidae Genus Species: one species (see Table 1). Superfamily: Phalangeroidea Family: Phalangeridae Genus Species: six species in four genera (see Table 1). Etymology See Strahan (1981).

2.2 Subspecies See Strahan (1995).

2.3 Recent synonyms Synonyms for Australian species can be found in Strahan (1995) and McKay (1988a, 1988b, 1988c, 1988d).

The dietary niches of possums and gliders limit their body size, with larger species being folivorous and small species, that have higher energy requirements on a mass-specific basis, being limited to energy-rich food items such as nectar, sap and arthropods (Table 2; Smith and Lee 1984; Lee and Cockburn 1985). Of the different food types, leaves and stems from plants are high in structural carbohydrates and low in material that is easily metabolised (Eisenberg 1981). Utilisation of plant fibre is more efficient for larger mammals because of their lower energy requirements relative to gut capacity (Van Soest 1982; Freudenberger et al. 1989; Justice and Smith 1992). Although plant material is a more ubiquitous food resource than other food types (such as exudates or flesh) for arboreal folivores, the consumption of eucalypt and other foliage as the major component of their diet presents several problems for Australian possums and gliders. These include the presence of toxic secondary compounds (xenobiotics) such as essential oils and tannins, and the

Possums and Gliders

Table 1. Species of possums and gliders in Australia and their conservation status. VU – vulnerable, EN – endangered, LR – lower risk, nt – near threatened, lc – least concern. Common Name

Scientific Name

Weight (g)

IUCN Status

EN

Superfamily Burramyoidea Family Burramyidae Mountain Pygmy-possum

Burramys parvus

30–82

Long-tailed Pygmy-possum*

Cercartetus caudatus

25–40

LR (lc)

Western Pygmy-possum

Cercartetus concinnus

8–20

LR (lc)

Little Pygmy-possum

Cercartetus lepidus

6–9

LR (lc)

Eastern Pygmy-possum

Cercartetus nanus

15–43

LR (lc)

Superfamily Petauroidea Family Petauridae Striped Possum*

Dactylopsila trivirgata

246–528

LR (lc)

Leadbeater’s Possum

Gymnobelideus leadbeateri

100–166

EN

Yellow-bellied Glider

Petaurus australis

450–700

LR (nt)

Sugar Glider*

Petaurus breviceps

85–160

LR (lc)

Mahogany Glider

Petaurus gracilis

340–500

EN

Squirrel Glider

Petaurus norfolcensis

190–300

LR (nt)

Family Pseudocheiridae Lemuroid Ringtail Possum

Hemibelideus lemuroides

750–1140

LR (nt)

Greater Glider

Petauroides volans

900–1700

LR (lc)

Rock Ringtail Possum

Petropseudes dahli

1280–2000

LR (lc)

Common Ringtail Possum

Pseudocheirus peregrinus

650–1100

LR (lc)

Western Ringtail Possum

Pseudocheirus occidentalis

900–1100

VU

Green Ringtail Possum

Pseudochirops archeri

670–1350

LR (nt)

Daintree River Ringtail Possum

Pseudochirulus cinereus

700–1450

LR (nt)

Herbert River Ringtail Possum

Pseudochirulus herbertensis

800–1530

LR (nt)

Tarsipes rostratus

7–12

LR (lc)

Acrobates pygmaeus

10–14

LR (lc)

Superfamily Tarsipedoidea Family Tarsipedidae Honey Possum Family Acrobatidae Feathertail Glider Superfamily Phalangeroidea Family Phalangeridae Southern Common Cuscus*

Phalanger intercastellanus

1500–2200

LR (nt)

Common Spotted Cuscus*

Spilocuscus maculatus

1500–4900

LR (lc)

Short-eared Possum

Trichosurus cunninghami

2500–4500

LR (lc)

Mountain Brushtail Possum

Trichosurus caninus

2500–4500

LR (lc)

Common Brushtail Possum

Trichosurus vulpecula

1200–4500

LR (lc)

Scaly-tailed Possum

Wyulda squamicaudata

1350–2000

LR (nt)

* also occurs in New Guinea and/or surrounding islands From Flannery (1995a, 1995b), Strahan (1995) and Maxwell et al. (1996)

generally low digestible energy and crude protein content of the leaves (Hume et al. 1984; Hume 1999). Among the possums and gliders, the greater glider Petauroides volans (and potentially lemuroid ringtail possums) appears to be the only strict folivore, with all other members of the Pseudocheiridae and

Phalangeridae supplementing their diet with food that is more easily digested such as blossoms, flowers, fruit, invertebrates and even small vertebrates (Table 2). The common ringtail possum and the green ringtail possum are the smallest arboreal marsupials with a predominantly folivorous diet and appear to be at the

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Table 2. Diets of different genera of possums and gliders. Families are listed in approximate order of increasing body size to reflect the relationship between diet and body size. Genus

Diet

Reference

Nectar, pollen only – exudivore

1, 2, 3

Nectar, manna, sap, blossoms, insects – exudivore

3, 4, 5, 6

Burramys

Seeds, fruits, invertebrates – exudivore

3, 7, 8

Cercartetus

Nectar, pollen, invertebrates, small vertebrates – exudivore

3, 5, 9, 10, 11, 12

Tarsipedidae Tarsipes Acrobatidae Acrobates Burramyidae

Petauridae Dactylopsila

Invertebrates, exudates, fruit, nectar – exudivore

3, 13, 14, 15, 16

Gymnobelideus

Exudates, invertebrates, nectar – exudivore

3, 17

Petaurus

Exudates, invertebrates, nectar, pollen, fruit – exudivore

3, 18, 19, 20, 21

Hemibelideus

Almost exclusively leaves – folivore

3

Petauroides


Pseudocheiridae

Some buds and flowers – folivore

3, 22

Petropseudes

Flowers, fruits, leaves – folivore

3

Pseudocheirus

Eucalypt leaves, flowers, fruit – folivore

3,23

Pseudochirops


3

Pseudochirulus

Leaves, fruits, flowers – folivore

3

Phalanger

Leaves, fruits, flowers, insects, small vertebrates, eggs – folivore

3

Spilocuscus

Leaves, fruits, flowers, some meat – folivore

3

Trichosurus

Eucalypt leaves, fruits, buds, flowers, fungi, occasionally meat and bark – folivore

3

Wyulda

Leaves, flowers, fruit, insects – folivore

3, 24

Phalangeridae

References: 1 Vose 1973; 2 Richardson et al. 1986; 3 Strahan 1995; 4 Turner 1984a; 5 Huang et al. 1987; 6 Goldingay and Kavanagh 1995; 7 Mansergh et al. 1990; 8 Mansergh and Broome 1994; 9 Hickman and Hickman 1960; 10 Turner 1984b; 11 Arnould 1986; 12 Smith 1986; 13 Fleay 1942; 14 Smith 1982a; 15 Handasyde and Martin 1996; 16 Rawlins and Handasyde 2002; 17 Smith 1984a; 18 Henry and Craig 1984; 19 Menkhorst and Collier 1988; 20 Howard 1989; 21 Jackson 2001; 22 Marples 1973; 23 Pahl 1987a; 24 Runcie 1999.

limit in size to be folivorous. To maximize food digestion, the common ringtail possum is caecotrophic (reingesting soft faeces of high nutritive value derived from caecal contents) in order to obtain access to protein, energy, and vitamins that would otherwise be lost because of poor absorption in the caecum and proximal colon (Chilcott 1984; Hume et al. 1984; Chilcott and Hume 1985). Cork and Foley (1991) noted that virtually no utilization of tree foliage is seen in primate, marsupial or rodent species smaller than approximately 700 g. They proposed this as the absolute evolutionary limit for foliage to be a major part of the diet, without supplementation with other more easily digestible matter such as flowers and fruit. Indeed, the smallest pseudocheirid possum, the pygmy ringtail, which has a body weight of only 105–206 g, appears to eat more digestible food types, such as epiphytic lichens and mosses, and to eat only very

small portions of leaves (Flannery 1995b). Similar observations have been made of the slightly larger (335–380 g) New Guinean lowland ringtail possum Pseudochirulus canescens (Flannery 1995b). All members of the Petauridae, Burramyidae, Acrobatidae and Tarsipedidae (Table 2) weigh less than the common ringtail possum and all eat foods that are more easily digested. Their diet consists of insect and plant exudates such as nectar (and pollen), tree sap, manna, insect honeydew and, in some species, fruit and seeds, in order to obtain their energy requirements (Table 2). As these substances are very low in protein, dietary protein requirements are supplied through the consumption of arthropods, pollen and, occasionally, small vertebrates. Within the Petauridae, Burramyidae, Acrobatidae and Tarsipedidae, protein is obtained from a variety of

Possums and Gliders

Table 3. Average longevity (years) of different genera of possums and gliders in the wild and in captivity. Number in brackets refer to the oldest known longevity; families are listed in approximate order of increasing body size. Genus

Wild

Captivity

References

1

1 (M), 2–3 (F)

1

3-5

2–3 (8)

2, 3, 4, 5

Burramys

13

4 (M), >10 (F) (11)

6, 7

Cercartetus

5

3–5 (10)

4, 8, 9

Dactylopsila

–

5–6

10, 11

Gymnobelideus

–

5–10 (12)

12, 13

Petaurus

4–6

5–8 (14)

2, 14, 15, 16, 17, 18, 19, 20, 21, 22

Tarsipedidae Tarsipes Acrobatidae Acrobates Burramyidae

Petauridae

Pseudocheiridae Petauroides

–

10–12 (15)

23, 24

Pseudocheirus

>6

5–6 (8)

25, 26, 27, 28, 29

Phalanger

–

7–9

30

Spilocuscus

–

7–9 (11)

31

Trichosurus

10–11 (13)

8–12 (17)

2, 5, 14, 32, 33, 34, 35, 36, 37

Phalangeridae

References: 1 F. Bradshaw pers. comm.; 2 Flower 1931; 3 Fleming and Frey 1984; 4 Ward 1990a; 5 Strahan 1995; 6 Mansergh and Scotts 1989; 7 Mansergh and Scotts 1990; 8 Atherton and Haffenden 1982; 9 Ward 1990b; 10 F. Wheeler and A. McKenna pers. comm.; 11 T. Carmichael pers. comm.; 12 Smith 1980; 13 Smith 1984b; 14 Mitchell 1911; 15 Henry and Craig 1984; 16 Henry and Suckling 1984; 17 Suckling 1984; 18 Craig 1985; 19 Goldingay and Kavanagh 1990; 20 Slater 1997; 21 Booth 1999; 22 Jackson 2000a; 23 Henry 1984; 24 Henry 1985; 25 Thomson and Owen 1964; 26 How et al. 1984; 27 Pahl 1987a; 28 Pahl and Lee 1988; 29 Ong 1994; 30 pers. obs.; 31 Fleay 1949; 32 MacLean 1967; 33 Crawley 1970; 34 Crawley 1973; 35 How 1981; 36 Barnett et al. 1982; 37 Lindenmayer et al. 1991.

sources (Table 2). The striped possum eats large numbers of ants, small stingless bees Trigona spp., termites, wood boring larvae and the larvae of several other insects (Troughton 1941; Smith 1982a; Handasyde and Martin 1996). Fleay (1942) found that captive striped possums caught and ate house mice Mus musculus. Mahogany gliders consume green ants, other insects, spiders, pollen and acacia arils (Van Dyck 1993; Jackson 2001). Leadbeater’s possums consume tree crickets, beetles, moths and spiders (Smith 1984a); the yellow-bellied glider eats a variety of arboreal arthropods, primarily tree crickets, adult and larval beetles, caterpillars, spiders and moths (Henry and Craig 1984; Smith and Russell 1982). Squirrel gliders consume pollen and various insects such as caterpillars and beetles (Menkhorst and Collier 1988). Squirrel gliders have also been known to kill mice in captivity (Troughton 1941), and there is a record of one killing a magpie-lark Grallina cyanoleuca in the wild and eating its eggs (Winter 1966). Another was observed harassing a nesting common bronzewing Phops cholcoptra until removing it and eating the eggs (Holland 2001). Sugar gliders consume moths, scarabaeid beetles and pollen (Smith 1982b; Howard 1989);

pygmy-possums Cercartetus spp. consume insects and pollen (Hickman and Hickman 1960). Feathertail gliders eat pollen and insects, while the honey possum consumes pollen and has been observed eating mealworms and small moths in captivity (Vose 1973; Turner 1984a, 1984b; Richardson et al. 1986). Pollen is high in protein and although it is protected by a tough exine coat, the nitrogenous cell contents are large components of the diet of several marsupials including the honey possum, eastern pygmy-possum and feathertail glider (Stanley and Linskins 1974; Wooller et al. 1983; Turner 1984a, 1984b; Richardson et al. 1986). Pollen is also a significant protein source for larger possums including sugar gliders (Goldingay et al. 1987; Howard 1989), squirrel gliders (Menkhorst and Collier 1988), mahogany gliders (Jackson 2001) and yellow-bellied gliders (Goldingay and Kavanagh 1990; Quin et al. 1996).

3.5 Longevity 3.5.1 Wild There is a wide variation in the longevity of the different groups of possums and gliders in the wild. Typical

209

210


A

I

II

B

I

III

II

IV

III

V

IV

Figure 1. Typical wear patterns of upper incisors of Petaurus gliders, showing the front view (a) and the ventral aspect (b). See Table 4 for information on the age related to each tooth wear stage. Derived from Alexander (1981) and Suckling (1984) with permission.

longevity is from 1–11 years, and generally increases with increasing body size (Table 3). 3.5.2 Captivity There is a wide variation in the longevity of the different groups of possums and gliders in captivity. The smaller possums in the families Tarsipedidae, Burramyidae and Acrobatidae typically live for 1–12 years while the larger ones such as the Petauridae, Pseudocheiridae and Phalangeridae live for about 4–17 years (Table 3). 3.5.2 Techniques to determine the age of adults Various parameters including body weight, patagium colour, scent gland development, pouch development and tooth wear are usually used in combination to determine the age of possums and gliders. Three methods of tooth wear assessment can be used to determine the age or relative age of petaurids: ■ The degree of flattening (caused by wear) of the upper incisors when viewed from the anterior gives a relative age (Fig. 1a) ■ The degree of wear and proportion of dentine exposed on the upper incisors when viewing the ventral surface gives an approximate age (Fig. 1b; Table 4) ■ The colour and wear of the lower incisors and the presence of lateral cracks gives an approximate age – young animals have white lower incisors with no lateral cracks, while older animals have teeth that are more discoloured and develop an increasing number of lateral cracks with age. Older animals may have part of the lower incisors completely chipped off (Table 4). Body weight is a useful indicator of age until approximately 18 months for these species (Table 4).

Several techniques have been examined to determine age in ringtail possums (Fig. 2; Table 5) and common brushtail possums including tooth wear and growth rings of the teeth, however only tooth wear can be used on live animals. The tooth wear index for brushtail possums uses the upper left first molar to examine wear (generally while the animal is under anaesthetic)(Fig. 3) and although there is variation in wear between individuals it provides an approximate age (Winter 1980; Cowan and White 1989). Longevity in brushtail possums has been determined from dead animals by decalcifying molars in ‘RDO’, sectioning with a freezing microtome and staining with haematoxylin (Clout 1982). The sections are then observed under a microscope and the numbers of darkly stained bands are counted, where the number of bands equals the number of years.

4. Housing requirements 4.1 Exhibit design 4.1.1 General principles All possums and gliders are generally best displayed in nocturnal houses, due to their nocturnal behaviour. The exception is the bear cuscus Ailurops ursinus from Sulawesi, which is, apparently, diurnal (Flannery 1995a; Dwiyahreni et al. 1999). Smaller species, such as pygmy-possums, feathertail gliders and honey possums can be held in relatively small enclosures of about 1 m3, though it is preferable to provide a taller exhibit for the feathertail gliders due to their highly mobile acrobatic and gliding behaviour. Larger species such as the petaurids, pseudocheirids and phalangers require a significantly larger area of at least 4 m3.

Possums and Gliders

Table 4. Age-estimation parameters of mahogany, squirrel and sugar gliders. Parameter

Estimated age (years) 3

Males

< 300

> 300

> 370

> 370

Females

< 280

> 280

> 330

> 330

Males

< 190

> 190

> 210

> 210

Females

< 170

> 170

> 190

> 190

Weight of mahogany gliders (g)

Weight of squirrel gliders (g)

Weight of sugar gliders in North Queensland (g) Males

< 60

> 60

> 80

> 80

Females

< 50

> 50

> 70

> 70

Weight of sugar gliders in Northern New South Wales (g) Males

< 100

> 100

> 120

> 120

Females

< 80

> 80

> 100

> 100

Heavy to very heavy. Usually cracked. (Fig. 1bIV)

Mahogany gliders, squirrel gliders and sugar gliders Wear of upper incisors

None to slight (Fig. 1bI)

Slight to moderate. Sometimes cracked. (Fig. 1bII)

Moderate to heavy. Often cracked. (Fig. 1bIII)

Wear of lower incisors

White, no cracks

Slight discolouration, lateral cracks slight

orange discolouration, lateral cracks obvious. Occasionally chipped teeth in old animals. Yellow

Patagium colour Frontal gland (males) Pouch

White

Cream-yellow

Not developed

Partially to well developed

Small and shallow with fine white hairs; teats 1mm long

Larger and deeper than in females that had not bred. Yellow/orange hairs with black scale. Teats >1mm

Yellow-orange

From Alexander (1981), Suckling (1984), Quin (1995) and Jackson (2000a)

All possum and glider enclosures need to have good foliage cover, although in exhibits the foliage should be thinned out to give the public adequate viewing. Table 5. Age classes responding to the seven tooth wear classes. Tooth wear class (from Figure 2

Estimated age class (months)

1

0–18

2

7–30

3

7–36

4

13–43

5

19–48

6

25–60

7

31–48

From Pahl (1987b)

4.1.2 Exhibit requirements for different groups of possums and gliders The different species of possums and gliders require different methods of display, maintenance in off-exhibit areas, and in some cases, different arrangements to achieve successful breeding. 4.1.2.1 Honey possum Although honey possums have been held in smaller enclosures and indoors, successful breeding has occurred in an outdoor enclosure. This enclosure measured 4 × 4 × 2 m and was constructed of 1cm2 wire mesh, overlaid with fly screen in order to prevent the escape of any young. It was planted out with species of flowering plants such as Banksia, Isopogon, Grevillea, Eremophila, Callistemon and Adenanthos. Refuge areas were provided by planting small saplings of Corymbia calophylla and

211

212


Figure 2. Estimates of age in ringtail possums using tooth wear. Position and area of dentine (shaded) exposed in seven classes of tooth wear of the first molar (M2) of the upper jaw. Taken from Pahl (1987b).

Kennedya coccinea (Bradshaw et al. 2000). Although nest boxes were provided they were generally not used, with small rock piles or dense ground cover being used instead. The successful breeding is thought to be the result of the possums having more exercise than in an indoor enclosure, thus preventing obesity, although the synchronicity of births in mid-February also suggests an environmental cue (Bradshaw et al. 2000).

animals. Small hollow logs, with access into them, are also of use. A substrate of leaf litter, sand or dirt works well. Temperature control is also important, as temperatures above 25°C can result in mortality, particularly for mountain pygmy-possums (pers. obs.). Apart from the suggested wooden nest boxes, coconut shells with a large hole cut in the side work well and can be hung up in the branches in the enclosure.

4.1.2.2 Feathertail glider

4.1.2.4 Petaurids Petaurids generally live in tree hollows, however there are several records of Leadbeater’s possum living on the ground. An individual that was known to live in a woodpile lived happily alongside the family dog and bantams, and formed a small rounded nest from bark stripped from the firewood (Kellas and Kellas 1999). In captivity they should be provided with a network of branches throughout the enclosure which can range from vertical branches close enough together (eg up to 1 m) to allow jumping between, to a network of branches, suspended from the roof, that provides a runway. At least some of these branches should be species of eucalypts with stringy bark, as the possum will tear off strips of this for nesting material. Gliding petaurids require far fewer branches to move about, due to their ability to glide. Having larger gaps between branches can encourage their gliding ability. Striped possums should be provided with branches for climbing and to chew into. Wooden logs, such as eucalypts and acacias, with obvious wood boring insects

Feathertail gliders are easily maintained in small enclosures that contain a network of small (and a few larger) branches, substrate such as leaf litter and a surplus of nest boxes. They are excellent climbers and can easily climb over the smooth surface of glass. Great care is needed to ensure there are no gaps in the walls or they will readily escape. Care also needs to be taken when accessing the enclosure as individuals are often near the doorway, due to their ability to climb walls, and can escape if you are not careful, particularly in the relative darkness of a nocturnal house. The likelihood of this occurring can be reduced by servicing the enclosure during the day (light) cycle when they are generally in their nest boxes and it is easier to see them if they are out in the enclosure (W. Gleen pers. comm.). 4.1.2.3 Pygmy-possum Pygmy-possums should be provided with a network of branches to climb, several rocks to climb over and under (particularly for the mountain pygmy-possum) and should be supplied with at least one nest per pair of

Possums and Gliders

1

0.9

Cusps high and pointed with no apparent wear

2

1.2

Lingual cups with points rounded but with no dentine exposed

3

1.7

Small cresents of dentine exposed on ligual cusps, but none on labial cusps

3.7

Cresents of dentine on lingual cusps larger, but still high and rounded; dentine exposed on at least one labial cusp, but not joined to dentine cresent of lingual cusp

5.6

Lower limit; dentine of at least one labial cusp joined to dentine cresent of lingual cusp

6.8

Upper limit; dentine of lingual cusps joined, no longer appearing as cresents; dentine of both labial cusps joined to lingual cusps, but still appear as narrow strips along the cusp ridge

8.9

Lower limit; lingual cusps flattened, and broad band of exposed dentine between the two; dentine on labial cusps no longer a narrow strip but a broad band

10.7

Upper limit; both lingual and labial cusps flattened, with large areas of exposed dentine, but still with an enamel indentation between anterior and posterior lingual cusps

11.4

Cusps completely obliterated and crown of tooth dished; no enamel indentation between anterior and posterior lingual cusps

4

5

6

7

Figure 3. Estimates of age (years) in brushtail possums using tooth wear. Position and area of dentine (shaded) exposed in classes of tooth wear of first molar (M1) of the upper jaw. Derived from Winter (1980) and Cowan and White (1989).

should be provided so the possums can feed using their incisors (Carmichael 2000). Care should be taken when housing them in wooden structures, as they are capable of chewing their way through. Hardwood in good condition is strong enough to withstand the occasional nibble but is not recommended for keeping striped possums over an extended period (Carmichael 2000). 4.1.2.5 Ringtail possums and greater glider Common ringtail possums typically forage in the mid to low canopy, whereas greater gliders typically forage higher in the canopy (pers. obs.; Davey 1984). Therefore, a series of branches arranged in a similar way to those used for the petaurids should provide adequate runways to climb around the enclosure.

4.1.2.6 Cuscuses, brushtail possums and scaly-tailed possum These species need a number of strong branches to allow them to climb around the enclosure. They will also readily forage on the ground so food can be supplied either on the ground or on a feed platform. Due to their tendency to remain inactive for long periods as a result of their diet, it is possible to carefully light the nest box or tree trunk so that they are visible when resting. Take care that the nest is not immediately on the other side of glass, as the public will tap it constantly and unnecessarily stress the animals. The lighting may not work if the nest box or log is too small as you will only be able to see the fur on the animal’s back when it curls up to sleep.

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For the larger possums that are held in larger enclosures, take care not to fill the enclosure with too much foliage. Ideally the possum should be visible in most, if not all, positions in the enclosure except the nest box (and even this could potentially be viewed). By thinning out some branches it is possible to provide the possums with a feeling of protection while also allowing the public to see them. In the centre (and ideally elsewhere) there should be horizontal branches that can accommodate a food dish and also connect thicker areas of foliage.

4.2 Holding area design Holding areas for possums and gliders can be of relatively simple design. The small possums such as the pygmy-possums, feathertail gliders, and honey possums can be easily held in wooden boxes with one or more panels of wire mesh. Great care needs to be taken with enclosures for small possums such as feathertails as they have been observed to escape from enclosures with 1 cm2 mesh (S. Ward pers. comm.). Eastern pygmy-possums, mountain pygmy-possums, and honey possums have been bred successfully in enclosures that contained a soil floor and were exposed to the weather so that grass and shrubs could grow. The pygmy-possums have been held in large enclosures up to approximately 10 m × 5 m × 3.3 m high that allow ample opportunity for the animals to forage, organize their social behaviour and experience natural light cycles and weather, which appear to be important in breeding these species. Possums such as sugar gliders, Leadbeater’s possum and some larger species can be housed in simple wire framed structures that can be set up as a series of adjacent enclosures, remembering, as mentioned previously, that striped possums need to be held in well built enclosures. In this case the enclosures can be narrower than recommended but longer, eg 2 m wide and 5+ m long. These enclosures should have at least part of the roof area covered (eg 1.5–2 m), under which the nest boxes and food should be placed. The floor of these enclosures can be concrete with leaf litter or sand, hollow logs and tussocks. Ideally an enclosed service area to each enclosure should be provided to allow easier servicing during poor weather and additional security in case an animal escapes from its enclosure.

Table 6. Minimum area of enclosures recommended for pairs of animals of different genera of Australian possums and gliders. Families are listed in approximate order of increasing body size. Genus

Area (L × W × H)(m)

Additional Floor Area for Each Extra Animal (m)

1.0 × 1.0 × 1.0 – 3.0 × 3.0 × 2.0

0.30 × 0.30

Burramyidae Burramys

(breeding) 1.0 × 1.0 × 1.0

0.30 × 0.30

Dactylopsila

3.0 × 3.0 × 3.0

2.0 × 2.0

Gymnobelideus

2.8 × 2.8 × 3.0

2.0 × 2.0

Petaurus – small

2.8 × 2.8 × 3.0

1.0 × 1.0

Petaurus – medium

3.7 × 3.2 × 3.0

1.5 × 1.5

Petaurus – large

3.5 × 3.5 × 3.0

2.0 × 2.0

Hemibelideus

2.8 × 2.8 × 3.0

2.0 × 2.0

Petauroides

2.8 × 2.8 × 3.0

2.0 × 2.0

Petropseudes

2.8 × 2.8 × 3.0

2.0 × 2.0

Pseudocheirus

2.8 × 2.8 × 3.0

2.0 × 2.0

Pseudochirops

2.8 × 2.8 × 3.0

2.0 × 2.0

Pseudochirulus

2.8 × 2.8 × 3.0

2.0 × 2.0

1 × 1 × 1 to 4 × 4 × 21 (breeding)

0.30 × 0.30

1.0 × 1.0 × 1.0

0.30 × 0.30

Phalanger

3.5 × 3.5 × 3.0

2.0 × 2.0

Spilocuscus

3.5 × 3.5 × 3.0

2.0 × 2.0

Trichosurus

3.5 × 3.5 × 3.0

2.0 × 2.0

Wyulda

3.5 × 3.5 × 3.0

2.0 × 2.0

Cercartetus Petauridae

Pseudocheiridae

Tarsipedidae Tarsipes

Acrobatidae Acrobates Phalangeridae

1 Used by Bradshaw et al. (2000) to breed successfully.

mountain pygmy possums, should be given larger enclosures for breeding.

4.4 Position of enclosures In many cases possums and gliders will be held in nocturnal houses, however when they are held in outdoor enclosures they should be well protected from the prevailing winds and poor weather with the nest boxes out of full sunlight.


4.5 Weather protection

Table 6 contains recommendations on the areal requirements of different groups of possums and gliders. An additional 25% floor space is suggested for each extra individual. Some species, such as honey possums and

The nest boxes, which are usually hanging off one of the walls or on a platform, should be under shelter away from the wind and rain. The remainder of the enclosure can be relatively open to allow airflow.

Possums and Gliders

4.6 Temperature requirements Heating is generally not required unless there are sustained periods of low temperatures, such as weeks when the temperature is below approximately 5°C. In most cases the various species are well adapted to low temperatures and go into torpor to conserve energy if required (See Section 9.1). Indeed, the occurrence of torpor may even be a trigger for breeding in some species such as the mountain pygmy possum (which normally lives in colder alpine areas of New South Wales and Victoria). Species that undergo torpor, especially the mountain pygmy possum, should not be overheated and generally do not require additional heat. The mountain pygmy possum should be maintained at temperatures below 25°C (preferably 10–20°C). Temperatures above this are known to cause mortality (pers. obs.). Similarly, observations by Fleming (1985a) showed that mountain pygmy possums were noticeably stressed by ambient temperatures above 29°C (lying on their flanks, ears fully expanded, tail engorged with blood and saliva spread on their forepaws) and exposure to temperatures of 33°C for less than an hour was found to be lethal. Species that typically live in tropical areas in the wild may need additional heat to mimic the wild conditions. Heating may also increase the activity of the smaller species during cold weather, as they will be less likely to go into torpor, however, as mentioned above, the effect this has on reproduction is not known.

4.7 Substrate In most cases the substrates are typically sand or leaf litter. Holding enclosures for small possums may be covered in paper for ease of cleaning.

4.8 Nest boxes In the wild, the different species use various locations (Table 7). Most of the larger species use tree hollows lined with leaves, although several species live in rocky crevices and the ringtail possums may build their own nests (known as dreys) independent of tree hollows (Thomson and Owen 1964). Smaller species generally live in birds’ nests, grass tussocks, logs, stumps, and even underground. An outline of different known nest types for the various genera of possums and gliders is given in Table 7. Nest boxes should be supplied for all species of possums as they provide security, a place for raising young and, if provided in enclosures that are open to the elements, protection from the weather. Several studies in the wild, and numerous captive observations, have shown that most species of possums, including

feathertail gliders, pygmy-possums, sugar gliders, squirrel gliders, yellow-bellied gliders, Leadbeater’s possum, ringtail possums, greater gliders and mountain and common brushtail possums and cuscus, will readily use nest boxes if they are of adequate size (Menkhorst 1984a, 1984b; pers. obs.). Striped possums have been offered hollow logs that provide a comfortable snug fit, without being too roomy (Carmichael 2000). In general, the nest box should allow one or more individuals (as suggested by their social structure – see Table 10) to comfortably inhabit it and the nest opening should be as small as possible while still allowing the possum access. A large access door (preferably taking up the whole side) should be placed on the side of the nest box to allow easy keeper access to the animals inside. An overhang, of approximately 10 cm, on the front of the nest box is also recommended, particularly if it is to be placed outdoors. The inside of the nest box should include a thin piece of wood, with marks cut into it, attached to the side to allow the possums (particularly juveniles) to climb out of the box. Table 8 gives an outline of approximate nest box sizes.

4.9 Enclosure furnishings It is important that the enclosure has a network of climbing branches to allow maximum use of the vertical space available. Fresh branches with leaves are highly recommended as they provide both cover to allow the possums and gliders to feel secure and also food for the folivores and behavioural enrichment due to their smell. Gliding possums should ideally be given some open spaces in which to glide. Smaller species such as mountain pygmy-possums may be given rock piles to mimic the scree slopes in which they live, however great care must be taken stacking them so they do not fall and cause injury or death. It may be an advantage to cover one or more nest boxes with rocks.

5. General husbandry 5.1 Hygiene and cleaning All enclosures should be cleaned daily to remove faecal matter and uneaten food. It is very important to keep the feed area as clean as possible due to the potential for health problems that can result from poor hygiene and bacteria entering the food. Drinking water dishes should be cleaned and refilled daily. When all individuals permanently leave an enclosure, it should be scrubbed out and cleaned as much as possible before new animals enter.

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Table 7. Nest type and location for various species of possums. Families are listed in approximate order of increasing body size. Common Name

Nest Type

Location

Ref.

Not known to build nests

Ground, bird’s nests, in grass tussocks or dense vegetation, hollow stems of grass trees

1, 2

Typically make egg-shaped nests with leaves such as eucalypt and casuarina, bark and tree fern fibre; lined with feathers or other soft and flexible material

Tree hollows, deserted ringtail dreys, telephone interchange boxes, old birds’ nests, power boxes

2, 3

Burramys parvus

Grass

Rocky crevice

4

Cercartetus spp.

Often none, can include a ball of fibrous bark of eucalypts, or grass; a good hollow for breeding nests works well

Tree hollows, forks of tea-trees, leaves of grass trees, on the ground inside logs or hollows, stumps, birds’ nests near ground, underground by digging into the soil

2, 5

Dactylopsila spp.

Leaves

Tree hollow or amongst clumped epiphytes

2


Large nest of shredded bark

Tree hollows

2

Petaurus spp.

Leaves

Tree hollows; a record of sugar gliders in grass on the ground

2, 6, 7


Leaves?

Tree hollows

2

Petauroides volans

Leaves?

Tree hollows

2

Petropseudes dahli

Not known to build a nest

Well protected rocky crevices

2

Pseudocheirus spp.

Spherical nests (dreys) in densely branching trees or shrubs and made of ferns, leaves, twigs, stringy bark, and lined with shredded bark and grass; hollows may or may not be lined with leaves

Dreys in tree branches or on the ground; also nest in tree hollows or tree stumps; Primarily use dreys if hollows not available

2, 8, 9

Pseudochirops spp.

Does not appear to use nests

Rests on branch in tree canopy

2

Pseudochirulus spp.

Leaves are known to be used

Tree hollows and epiphytic clumps

2

Phalanger spp.

None known

Tree hollow

2

Spilocuscus spp.

Thought to build a sleeping platform of leaves by drawing twigs under it

In thick canopy of a rainforest tree

2

Trichosurus spp.

General leaves of vegetation eg eucalypts, though not always used

Tree hollows, fallen logs, pipes, rock cavities and even termite mounds

2, 10, 11, 12


Not known

Rock piles, sunken rock piles, large rock slabs, underground rock crevices

13

Tarsipedidae Tarsipes rostratus

Acrobatidae Acrobates pygmaeus

Burramyidae

Petauridae

Pseudocheiridae

Phalangeridae

References: 1 F. Bradshaw pers. comm.; 2 Strahan 1995; 3 Fanning 1980; 4 Kerle 1984a; 5 Green 1980; 6 Morrison 1978; 7 Jackson 2000b; 8 Thomson and Owen 1964; 9 Augee et al. 1996; 10 Kean 1967; 11 Green and Coleman 1987; 12 pers. obs.; 13 Runcie 1999.

5.2 Record keeping

■

It is important to establish a system whereby the health, condition and reproductive status of captive possums and gliders are routinely monitored. Records should be kept of:

■ ■ ■ ■ ■

■

■

Identification numbers; all individuals should be identifiable Any veterinary examination conducted

■ ■

Treatments provided Behavioural changes or problems Reproductive behaviour or condition Weights and measurements Changes in diet Movements of individuals between enclosures or institutions Births with dam and sire if known Deaths with post mortem results.

Possums and Gliders

Table 8. Approximate nest box sizes (cm) for various species of possums. Measurements are internal sizes. Families are listed in approximate order of increasing body size. Length × Breath × Height

Entrance Size

Tarsipedidae Tarsipes rostratus

15 × 20 × 30

5

Acrobatidae Acrobates pygmaeus

15 × 20 × 30

5

14 × 12 × 10 to 25 × 18 × 11 14 × 12 × 10

5

Petauridae Dactylopsila spp. Gymnobelideus leadbeateri Petaurus spp.

20 × 30 × 45 20 × 30 × 45 20 × 30 × 45

5 5 5–7

Pseudocheiridae Hemibelideus lemuroides Petauroides volans Petropseudes dahli Pseudocheirus spp. Pseudochirops spp. Pseudochirulus spp.

20 × 30 × 45 20 × 30 × 45 20 × 30 × 45 20 × 30 × 45 20 × 30 × 45 20 × 30 × 45

8 8 8 8 8 8

Phalangeridae Phalanger spp. Spilocuscus spp. Trichosurus spp. Wyulda squamicaudata

20 × 30 × 45 30 × 40 × 55 20 × 30 × 45 20 × 30 × 45

15 20 15 15

Common Name

Burramyidae Burramys parvus Cercartetus spp.

5

species of possums and gliders. This is an excellent method of identification, however it can be expensive if many animals are implanted. PIT tags are a permanent method of identification but care must be taken when they are implanted as they may track out along the injection site. This may be avoided by sealing the entry wound with tissue glue (Vetbond®) or similar fast setting adhesive. The animal generally needs to be caught to confirm identification with a PIT tag reader. 5.3.2 Tattoos Tattooing the inside of the ear or inside hind leg has been used, however the tattoos tend to fade and they can only be used on the larger species. 5.3.3 Visual identification Often difficult, especially with smaller species, however visual identification of larger species is often possible using size, colour, sex and markings. 5.3.4 Ear tags Metal ear tags can work relatively well in the larger species, however they can cause sore wounds and are prone to tear out, particularly in species that have thin ears, such as the petaurids. When using eartags, care is needed to avoid veins within the ear when making the hole. In some cases it may be best to use a hole punch to create a hole first, then fit the tag (S. Ward pers. comm.).

From Menkhorst (1984b) and Arlidge et al. (1993).

The collection of information on each individual’s physical and behavioural patterns can contribute greatly to the husbandry of these species. It also allows the history of each individual to be transferred to other institutions if required and greatly facilitates a cooperative approach to data collection amongst institutions. In most of the larger institutions ARKS (for general information on births, transfers and deaths), SPARKS (breeding studbook for species) and MedARKS (veterinary information) are used. These systems have been developed by the International Species Information System (ISIS), which is part of the Conservation Breeding Specialist Group (CBSG) software. As these are standardized there is a high degree of efficiency in transferring information between institutions.

5.3 Methods of identification 5.3.1 Passive Integrated Transponder (PIT) tags These are implanted between the scapulae of individuals, over 10 g in body weight, and can be used on most

6. Feeding requirements 6.1 Captive diet 6.1.1 Honey possum Ad Lib Water Daily Diet (per animal) Lactating diet Warm water 810 ml Honey 350 ml Pollen 70 g Balance* 10 g Ration – 10 ml/animal/day

Non Lactating Diet 810 ml 300 ml 35 g 5g

* Balance – 100% pure ion exchange whey available from health food shops. * Diet used by Felicity Bradshaw et al. (2000; pers. comm.) and D. Philippe pers. comm.

Blend honey, pollen and approximately half the water in a blender until the pollen is broken down (approx. three minutes). Add remaining water and ‘Balance’ and blend briefly (approx. 30 seconds). Measure the sugar

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content using a refractometer (Brix); it should be 21%. Different types of honey will have different sugar contents and the volume may need to be adjusted to ensure the sugar percentage is correct. This mixture is stored frozen in appropriate portions (for no longer than one week) to prevent fermentation and is fed at the rate of 10 ml each per day in 10 ml syringes fixed upright on a spring clip and inserted through a hole in the cage. Water is provided in a similar way to the nectar or in bird water holders (Russell and Renfree 1989), though it does not appear to be used, particularly if the enclosure is open to the weather (Bradshaw et al. 2000). As males are preferably removed once the female has young she is then given the lactating diet and the male is given the non-lactating diet. When both males and females are together they should be given the lactating diet. Fresh flowers from eucalypts, bloodwoods, melaleucas, banksias and callistemons should be provided wherever possible. After several days the flowers can potentially be sprayed with a fine mist of nectar to increase possum activity. The only occurrence of captive breeding to date occurred in an enclosure that was planted with species of Banksia, Adenanthos, Isopogon, Grevillea, Dryandra and Callistemon. The amount of nitrogen fed was increased from the 5.6 mg (Russell and Renfree 1989) to 20 mg and the nitrogen from pollen increased from 15 to 54%. The Russell and Renfree (1989) diet is not recommended due to its low nitrogen content (F. Bradshaw pers. comm.). Instead, the diet above should be provided for lactating females and males (Bradshaw et al. 2000). 6.1.2 Feathertail glider Ad Lib Water Daily Diet (per animal) 3 ml Nectar mix* 1 g Mixed fruit – (sweet potato, melon, sweet corn, apple, pear, orange, banana) (can be large chunks 10 × 5 cm spiked onto a branch or nail; W. Gleen pers. comm.). Supplement Mealworm – once per week 1 Insect (including crickets and moths) – once per week 1 Pollen grain – once per week Blossoms as available * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

Fresh flowers from eucalypts, bloodwoods, melaleucas, banksias and callistemons should be

provided wherever possible. After several days the flowers can be sprayed with a fine mist of nectar to increase possum activity. 6.1.3 Pygmy-possums Eastern pygmy-possum Ad Lib Water Daily diet (per animal) 2.5 ml Nectar mix* 1 g Fruit – apple, banana, orange, pear or fruit in season Supplement Insect – 2–3 times per week 2 g Pollen grains – once per week. 2 g Pet health food – once per week. 1 Sultana – once per week Blossoms as available Fine seed mix especially during spring/summer * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

Fresh flowers from eucalypts, bloodwoods, melaleucas, banksias and callistemons should be provided wherever possible. After several days the flowers can be sprayed with a fine mist of nectar to increase possum activity. Mountain pygmy-possum Ad Lib Water Daily Diet (per animal) 14 g Fine seed mix* 2 g Fruit and vegetables, eg apple, orange, pear, corn, sweet potato Sunflower seeds 2 Mealworms Supplement Dog chow or Eukanuba® Pet Food Kibble – twice per week 1–2 Crickets – 3–4 times per week 1 -- Almond or Walnut – 3–4 times per week 2 1 Moth – 3–4 times per week. * Diet used by Healesville Sanctuary.

Other food items that are readily consumed include raisins and earthworms, with foods such as apple, cheese, egg, pear, avocado, lettuce, sprouted wheat, mince, banana, orange, fly pupae, moths, tomato, carrot, potato and melon eaten in decreasing preference, with cat chow and rodent food not eaten at all (Arlidge et al. 1993).

Possums and Gliders

6.1.4 Petaurus gliders Sugar glider Ad Lib Water Daily Diet (per animal) Dog chow/ Eukanuba® Pet Food Kibble 6 g Fruit, chopped 1 tsp Nectar mix* 1 g Fly pupae 5 g Corn 2 g Sprouted seed* 2 Mealworms Supplement Pollen granules – once per week 3 Sultanas – 3–4 times per week 2 Sunflower seeds – once per week 1 g Pet health food (small cube) – once per week 1 Almond – once per week Insects – 3–4 times per week (eg moths) Acacia, eucalypts, other blossoms as available * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

10 Mealworms Supplement Eukanuba® Pet Food Kibble – once per week 1.5 g Pet health food – once per week 0.5 g Egg – once per week 0.4 g Pollen Insects (including crickets and moths) – 3–4 times per week 1 branch acacia/flowering gum per week * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

Fresh flowers from eucalypts, bloodwoods, melaleucas, banksias and callistemons should be provided wherever possible. After several days the flowers can be sprayed with a fine mist of nectar to increase possum activity. The quantity of food offered for other species of gliders should be adjusted according to body size to minimize the potential for overfeeding or underfeeding. In particular, the amount of nectar mix should be monitored as some species such as the gliders and pygmy possums can become very overweight.

Ad Lib Water

6.1.5 Striped possum Ad Lib Water

Daily Diet (per animal) 1 Eukanuba® Pet Food Kibble 20 g Mixed fruit and vegetables – 10mm cub - Avoid soft fruits 5 ml Nectar mix* 2 g Fly pupae 5 g Corn 1 g Sprouted seed* 2 Mealworms

Daily Diet (per animal) 15 g Live crickets 12 g Soaked primate pellets 20 g Mealworms 25 g Insectivorous bird mix 50 g Fruit eg apples, avocado, banana, black persimmon, canistel, cherry, custard apple, grape, lychee, mamey sapote, mango, mangosteen, melon, nectarine, orange, paw paw, peach, plum, rambutan, sapodilla

Squirrel glider

Supplement 0.4 g Pollen grains – once per week 1.5 g Pet health food – 10mm cube – once per week Cricket – 3–4 times per week Acacia, eucalypts, other blossom when available * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

Yellow-bellied glider Ad Lib Water Daily Diet (per animal) 30 ml Nectar mix* 15 g Mixed fruit 4 g Fly pupae

* Diet derived from London Zoo (F. Wheeler and A. McKenna pers. comm.) and Rainforest Habitat (Carmichael 2000)

Supplement Nectar mix given occasionally consisting of honey, boiled egg (with shell), high protein baby cereal, farex and water (F. Wheeler and A. McKenna pers. comm.). Decomposing rotten logs, such as eucalypts and acacias, with lots of borers should be supplied whenever possible to encourage natural foraging (Carmichael 2000). Insectivorous bird mix (Carmichael 2000) 50% Mildura cake (egg cake)* 15% Wombaroo Insectivore Mix 15% Egg and biscuit mix 10% Hard boiled egg

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5% Grated cheese 5% Fly pupae * See recipe below.

Egg cake recipe 2 kg Self-raising flour 100 g Margarine or butter 12 Eggs 750 g Sugar Add water to make up to normal cake mix consistency and bake in flat cake tin in moderate oven. (T. Carmichael pers. comm.) 6.1.6 Leadbeater’s possum Ad Lib Water Daily Diet (per animal) 15 ml Nectar mix* 3 g Mixed fruit 1 g Fly pupae 3–4 Mealworms Supplement Eukanuba® Pet Food Kibble – twice per week 0.2 g Pollen grains – once per week Insects (including crickets and moths) – 3–4 times per week Acacia branch weekly * Diet used by Healesville Sanctuary * See Section 6.1.10 for nectar mix formula

6.1.7 Ringtail possums Ad Lib Water Daily Diet (per animal) 4 g Apple 4 g Pear, or other hard fruits 4 g Carrot 3 g Banana 3 g Sprouted seed* 6 g Fly pupae Supplement 2 g Dog chow/ Eukanuba® Pet Food Kibble – twice per week 1 Almond – shelled – 3–4 times per week 5 g Grated egg and cheese – twice per week 5 Sultanas – 3–4 times per week Native flowers eg Banksia, eucalypts as available Fresh branches of foliage to eat eg E. ovata, E. dives, E. maculata and Leptospermum spp. * Diet used by Healesville Sanctuary

6.1.8 Greater glider Ad Lib Water Fresh branches of Eucalyptus leaves eg E. viminalis, E. radiata, E. fastigata, E. obliqua, E. ovata, E. cypellocarpa, E. umbra, E. intermedia, E. exserta and E. drepanophylla. Other species also known to be eaten M. quinquenervia * Diet derived from Foley et al. (1990) and Kavanagh and Lambert (1990) and captive observations.

There is no artificial diet for the greater glider as they are strict folivores and like koalas, must be fed eucalypt species. They need 45–50 g of dry matter of leaves per day (Foley et al. 1990). 6.1.9 Cuscuses, brushtail possums and scaly-tailed possum Brushtail possum Ad Lib Water Daily diet (per animal) 3 Eukanuba® Pet Food Kibble 30 g Medium apple ( 1--4 ) 40 g Orange ( 1--4 ) 35 g Banana ( 1--4 ) 35 g Carrot (medium) ( 1--4 ) 35 g Pear ( 1--4 ) 15 g Slice corn 6 g Sprouted seed* 3 g Greens, eg silverbeet, sow thistle, wandering jew, spinach 1 -- Kiwi fruit – when available 2 Supplement 3 g Egg and cheese – twice per week 3 g Sultanas or sunflower seeds – 3–4 times per week 1 Almond – 3–4 times per week Other fruits in season, eg kiwi fruit Fresh acacia and eucalyptus branches as available * Diet used by Healesville Sanctuary

Scaly-tailed possum Although a diet similar to that used for the brushtail possum is likely to be adequate, scaly-tailed possums have been fed on a mixture of rolled oats and crushed nuts with a small quantity of Farex, mixed with honey to a firm consistency (Fry 1971). They also appear to readily eat eucalypt leaves, casuarina nuts – from which they prise out the seeds and blossoms of eucalypt, grevillea, callistemon, melaleuca, hypocalymas, hibbertia,

Possums and Gliders

calothamnus, paw paw, tomato, guava, feijoia and rose. They readily eat nuts such as brazil, barcelona, cashew, pistachio, almonds and walnuts but usually ignore peanuts (Fry 1971). Branches of Trachymere sp., Xanthostemon sp., Planchonia careya and Eucalyptus sp. should also be provided (Runcie 1999). They usually reject gum leaves and don’t eat insects, meat or eggs at all (Fairfax 1982).

times to avoid stereotypic expectations. It is very difficult to increase the activity time of large folivores due to their slow metabolism and resulting high digestion times, however replacing foliage in exhibits regularly appears to stimulate activity (W. Gleen pers. comm.).

7. Handling and transport

Cuscuses The brushtail possum diet, enlarged or reduced according to body size, works well for cuscuses. Other food items they have been fed include sweet potato, yam, lettuce, and leafy vegetation from eucalypts and other plants (Menzies 1972; Shoemaker and Croxton 1982).

7.1 Timing of capture and handling

6.1.10 Nectar mix 900 ml Warm water 900 ml Honey 6 Shelled hard-boiled eggs 150 g High-protein baby cereal 6 tsp Sustagen (vitamin supplement)

7.2 Catching bags

Method 1. Add the warm water into a two litre jug and then slowly add the honey and stir so that it dissolves. 2. Blend the eggs (no shells) until mushy. 3. Add half the honey/water mix and blend. Add remainder of mix and blend. 4. Add Sustagen and half the baby cereal and blend. 5. Add remainder of baby cereal. Blend for 1.5 minutes to make lump free. 6. Can be stored for up to two weeks.

6.2 Supplements As per individual diets.

6.3 Presentation of food Most species of possums and gliders are generally fed with a feed dish placed either on the ground or on a platform placed on a side wall or on the trunk or branch of a tree. Captive observations suggest that the branches of eucalypts for greater gliders should be placed near the top of the enclosure, as they do not appear to like having to descend to feed (Collins 1973). In captivity, both exudivores and folivores have a tendency to eat what they need and then return back to their nest boxes. Therefore, to maximize the time they spend on display (particularly for the exudivores) the food should be spread out in small amounts (see Section 9.1). This will also increase their exercise and reduce the incidence of obesity. This strategy can be further enhanced by feeding at irregular

Possums and gliders are generally best caught during the day while they are asleep in their nest boxes. If they are held in a nocturnal house, you can often catch them early in the morning before the lights go out. Alternatively, they can be netted or trapped within the enclosure.

Smaller species can be easily held in calico cloth bags. The small to medium money bags used by banks are ideal for species below the size of a sugar glider, while the larger bank bags work well for the petaurids. Larger possums such as ringtails, greater gliders, brushtail possums and cuscus should be placed in larger cotton, calico or hessian bags. Feathertail gliders can be weighed in plastic bags (that are not sealed or have several small holes at the top to allow plenty of air to enter) using a fine scale spring balance as the weights will be more accurate and the animals easier to see and handle.

7.3 Capture and restraint techniques It is often easy to avoid direct handling or restraint of the possums (unless required for a checkup) as quiet individuals can generally be encouraged to move from the nest box into a bag (W. Gleen pers. comm.). If the animal or animals are to be moved to another enclosure, such as during an exhibit renovation, it is often easy to place a catching bag snugly in the nest box entrance and carefully carry the whole nest box to the new enclosure where the catching bag is removed. 7.3.1 Small possums Small species such as feathertail gliders and pygmy-possums can be easily picked up and held in the hand, as they generally do not bite or, if they do, it is not painful. 7.3.2 Medium to large possums and gliders Larger species, such as the petaurids and ringtail possums, will bite and scratch with their very sharp claws. These species should be caught and handled with care. They are best caught in their nest box by plugging

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(a) (b)

Figure 4. Handling techniques for (a) ringtail possums and petaurids and (b) brushtail possums. Note that long leather gloves are often used for handling brushtail possums. Photo by Stephen Jackson.

up the entrance hole with a cloth bag, taking the nest box off the wall, placing it on the ground in an enclosed well-lit area and then carefully opening the box and placing a catching bag over the animals. If they are out in the enclosure they can generally be caught with a hand-held net that is gently inverted into a catching bag (making sure the claws are not caught). Ringtail possums will usually try and escape from you if they are healthy and alert. Although they rarely stand and fight, like brushtail possums, they do possess a good bite and sharp claws that can inflict painful wounds. They can be caught with a catching net, home-made soft catchpole or can be covered with a blanket or bag and placed into a catching bag or cage/box for transport. Ringtail possums and petaurids can be restrained by holding the head and shoulders with one hand and the feet and tail with the other (Fig. 4a). Brushtail possums and cuscus can be caught in a similar way to petaurids or ringtail possums, however they can also be caught using a noose connected to a long pole. Try to place the noose around one armpit and the neck (like a winner’s sash) as this lessens the strangulation effect and you are able to manoeuvre the animal into a waiting carry bag, box or cage with more control. When catching brushtail possums or cuscus, use a large hessian bag. A pillowslip is not recommended for restraining brushtail or ringtail possums as pillowslips are usually made out of light cotton and tear easily, however calico bags work well. Always use any bag inside

out (ie overlock stitching showing on the outside) because it is very easy for animals to catch their claws in the stitching, resulting in the claws being pulled out, or the animal becoming entangled. Apart from a catchpole, a blanket can be spread out over the animal, giving a wider area in which to control it. When folded, blankets give handlers extra protection against being bitten through the blanket. With practice and gentle pressure, you will be able to determine the head and body of the possum through the blanket so that you can handle the animal. Once captured, brushtails and ringtails can be grabbed by the tail (at the base of the tail is best), and held in one of several ways: ■

■

■

Held totally off the ground. Possums tend to climb up themselves and can bite your hand or arm. This can be avoided in brushtail possums by slowly twirling the animal, as if you were mixing a cake. Lift the animal so that its front feet are still touching the ground or other surface such as a tree trunk. This usually eliminates the desire for the animal to try to climb up its own tail and bite you, as it is generally trying to get away. Hold the tail and the scruff of the neck or hold the neck between the index and middle fingers or between the thumb and index finger for large animals (Fig. 4b). This is best achieved if the animal is in a bag by pushing the head down to control it

Possums and Gliders

with one hand and running the other hand up the back until the grip around the neck can be achieved. Then hold the base of the tail with the other hand. You can confidently hold the animal’s tail securely under the armpit, freeing up one of your hands. When a possum is being held only by its tail, it can be transferred to a bag which is being held by a second person by swinging it in head first with one fluid motion. Once the animal’s body is at least 95% in the bag, quickly release your grip on its tail and, at the same time, lift the bag off the ground by gripping it around the neck. Some people find it easier to hold the bag themselves rather than trying to coordinate someone else swinging a bag around with an aggressive possum in their hand! If the animal is being held by the tail and the neck, it can be placed in the bag. Sometimes it is worth giving a short sharp flick when you let go of the animal into the bag. This propels the animal to the bottom of the bag, allowing you to tie it up. Once the animal is inside, unroll the top of the bag and tie it shut about seven-eighths of the way up the bag. Make sure you do not catch the tail or any other part of the body in the neck of the bag. It is often easier to hold the bag slightly upside down, with the opening held closed by your hand just prior to tying the bag up, as all possums generally climb upwards inside the bag. This should ensure that all parts of the possum are fully inside the bag. It is important not to place a possum in a hessian (or any other) bag on your lap as they can bite you through the bag. The darkness of a bag or box generally helps to calm the animal. Always place the animal in a dark cage or box and cover it with a blanket, or place the cage into the hessian bag before transportation. Nose injuries often occur from the possum trying to escape through the wire of the box. Usually the injury only consists of a blood nose, some swelling and scraping on top of the nose. Many people do not use gloves, as they tend to dramatically reduce the dexterity of the fingers, and the manoeuvrability of the hands. Having said that, given the very sharp claws and severe biting potential of large species, such as brushtail possums, some people swear by the use of long leather gloves. It may be worthwhile to have a pair handy and judge for yourself.

7.4 Weighing and examination A useful technique for examining the pouches of possums and gliders involves using a transparent plastic tube and an otoscope (Roberts and Kohn 1991). This

allows a clear view of the animal through the tube and confines the front limbs for examination. Weighing is best undertaken by placing the possum in a catching bag as described above and using either hanging or digital scales if available (especially for small species of possums).

7.5 Release Possums and gliders are generally best released either directly into the nest box, if that’s where they were first caught, on the ground or onto a branch or tree trunk.

7.6 Transport requirements 7.6.1 Box design The various species of possums and gliders are relatively easily transported. For short distances (eg several hours drive away) they are readily transferred in a catching bag, although they should ideally be placed in a nest box with the entrance plugged up, which acts as a secondary barrier if they escape from the bag. The nest box also provides protection, particularly for small species, from other objects that may crush them. Whenever possums and gliders are transported via air they should be placed in a recommended wooden box suggested by the International Air Transport Association (IATA 1999). Within this box the possum or glider can be held directly inside a bag (for shorter distances, eg several hours) and provided with nesting material so that it does not roll around too much. If the possum or glider is to travel longer distances it should be placed inside the box and provided with adequate nesting material. 7.6.2 Furnishings When placed in a wooden box, possums and gliders should be provided with clean, soft nesting material, such as shredded paper, whether they are placed inside a bag or not, to provide insulation and to stop them rolling around excessively during the trip. 7.6.3 Water and food When transporting animals in wooden boxes a water container, that has no sharp edges, should be secured to the side of the box. Water can be provided by placing a piece of clean sponge or rag inside the container and soaking it with fresh water or by using a dripper bottle. A small amount of food that is not likely to be easily spoiled can be provided. Females with pouch young should not be sent unless the young have only recently been born and are still permanently attached to the teat.

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7.6.4 Animals per box Ideally, all individuals should be housed separately during transport. The very small species such as honey possums and, possibly, feathertail gliders can be transported together if they have previously been held together in the same enclosure. Females with pouch young should not be transferred unless the young have only recently been born and are still attached to the teat. 7.6.5 Timing of transportation Ideally, animals should be transported overnight or in the cooler part of the day, though the temperature should not be too cold (eg between 10–20°C). 7.6.6 Release from the box Once in the new enclosure, open the bag or box, uncover the animal’s head so that it can see outside, and then leave it to emerge from the bag or box when it is ready. The bag and box are then removed once the animals have fully emerged.

8. Health requirements Edited by Dr Rosie Booth

8.1 Daily health checks Each animal should be observed daily for any signs of injury or illness. It is very important to be familiar with the normal behaviour of the group or individuals, as deviations from this pattern will assist in identifying if there is a potential problem. For example, places where an individual rests may change, it may not approach when it normally does, or approaches when it normally does not. Providing a small amount of food that the possum or glider prefers when you first enter the enclosure to encourage the animals to approach you will help you to observe their condition, movement and development. The most appropriate time to do this is generally when the enclosure is being cleaned or at feeding. During these times, each animal in the enclosure should be checked and the following assessed: ■ ■

■ ■ ■ ■ ■

■

Coat condition Fur on the enclosure floor or elsewhere, suggesting fighting or mating Discharges from the eyes, ears, nose, mouth or cloaca Appetite Faeces – number of pellets and consistency Changes in demeanour Injuries – including abrasions, swelling around the face, lameness and any asymmetry Presence and development of pouch young by observation of the bulge in the pouch

8.2 Detailed physical examination 8.2.1 Chemical restraint Pre-anaesthetic fasting is not required for adult animals as they are not prone to regurgitation (Vogelnest 1999). If being hand-reared, they should be fasted for one hour prior to anaesthesia to prevent the potential for regurgitation of the formula. Sedation can be undertaken with diazepam (Valium®) at 0.5–1.0 mg/kg given intramuscularly in the thigh muscle for minor procedures and handling (Vogelnest 1999). Injectable agents are useful for large or fractious possums. Tiletamine/zolazepam (Zoletil®) is the agent of choice. It can be used at 4–10 mg/kg intramuscularly or 1–3 mg/kg intravenously in the lateral coccygeal vein near the base of the tail (Vogelnest 1999). Tiletamine/ zolazepam (Zoletil®) is not recommended in Petaurus gliders, as it has been implicated in mortality of three healthy squirrel gliders (Holz 1992; Booth 1999). Inhalation anaesthesia via mask induction is preferred for small possums and gliders (R. Booth pers. comm.). Isoflurane is preferred for inhalation anaesthesia, although halothane in oxygen can also be used. Mask induction is simple, rapid and smooth with maintenance via the mask or intubation in larger species (Vogelnest 1999). 8.2.2 Physical examination The physical examination may include the following: ■

■ ■

■

■

Body condition – can be assessed by muscle palpation in the area over the scapula, spine and temporal fossa or by examining the base of the tail and allocating a condition score (Austin 1997). It can be assessed by palpation of muscle mass over the spine of the scapula, the temporal fossa and/or the base of the tail. With experience, condition scores can be allocated (Austin 1997; Viggers et al. 1998). Temperature – usually 35–36°C, taken via the cloaca. Weight – record and compare to previous weights. Trends in body weight give a good general indication of the animal’s state of health, provided age, sex and geographical location are taken into account. Animals in captivity should be weighed monthly to indicate trends. Pulse rate – normally 200–300 beats per minute at rest in sugar gliders (Booth 1999). The rate varies greatly with species, decreasing with increasing body size. The rate is taken over the femoral artery or direct heart rate. Respiratory rate – Normally 16–40 breaths per minute at rest in sugar gliders (Booth 1999), monitored via auscultation of the lungs, it varies

Possums and Gliders

■

■

■

■

■

■

greatly with the species, with the rate decreasing with increasing body size. Fur – check for alopecia, ectoparasites, fungal infections or trauma. Eyes ➝ Should be clear, bright and alert ➝ Normal bilateral pupillary light response ➝ Normal corneal reflex ➝ Should not have any discharges Also check for the presence of lumps over body and auscultation of lungs Cloaca ➝ Should be clean ➝ Check for faeces around the cloaca Pouch ➝ Condition of the pouch ➝ Check whether lactation is occurring by milking teats ➝ If pouch young are present, record sex, stage of development, weight if detached from the teat and measure to determine age from growth curves, if available Males ➝ Check testes – size (length, width, depth) and consistency (firm, not soft) ➝ Extrude penis and assess ➝ Check the size and activity of the sternal gland and forehead gland in Petaurus gliders.

8.3 Known health problems Possums and gliders suffer several problems in captivity. The majority of parasites and diseases that have been recorded are presented below. 8.3.1 Ectoparasites Cause – Numerous species of ectoparasites, including ticks and fleas, have been found on different possums and gliders. Leadbeater’s possum has been found with three species of fleas and one species of tick (Lindenmayer et al. 1994). Ectoparasites of Petaurus include mites of the genera Guntheria and Petauralges and an Atopomelid (Booth 1999). Some 19 species of mite, 10 species of tick and 10 species of flea have been found on brushtail possums (Presidente 1982a; Presidente et al. 1982; Presidente 1984). Brushtail possums have also been found with mites including Sarcoptes scabei resulting in sarcoptic mange (Munday 1988) and Trichosurolaelaps crassipes that is capable of causing irritation and alopecia of the lower back (Booth 1994). Ixodes holocyclus is a common ectoparasite of the mountain brushtail possum and less common on the common brushtail possum,

which has demonstrated resistance to their establishment (Booth 1994). Signs – Generally seen on the animal when captured, by excessive grooming, hair loss or inflamed skin. Diagnosis – Visual observations or a skin scraping and microscope examination to identify the parasites Treatment – Treated with acaricides, carbaryl powder (50 g/kg has been used topically and in the nest box to control mites (Booth 1999). Injectable ivermectin also controls a range of ectoparasites. Prevention – By maintaining good hygiene and routine examination of the fur. Quarantine of new arrivals helps prevent the introduction of ectoparasites. 8.3.2 Endoparasitic worms Cause – A number of cestodes, trematodes and nematodes have been found in or on various species of possums and gliders. Cestodes such as Bertiella have been recorded from the northern cuscus and the brushtail possum (De Mendonica 1983; Rose 1999). Nematodes have also been found in various species of cuscus held captive at Baiyer River (George 1982) and in the Australian spotted cuscus and southern cuscus (Speare et al. 1984). Numerous internal parasites have also been recorded from both species of brushtail possum including the lungworm Marsupiostrongylus and Trichostrongylus sp. (Presidente et al. 1982; Viggers and Spratt 1995; Rose 1999). The trematode Athesmia sp. has been found in the liver and the nematodes Parastrongyloides, Paraustrostrongyloides and potentially Paraustroxyuris have been found in the gut of sugar gliders (Spratt et al. 1990). A review of parasites found in tropical species of possums can be found in Speare et al. (1984). Signs – Not obvious unless diagnosed. May cause diarrhoea or ill thift (R. Booth pers. comm.). Diagnosis – Faecal flotation and the presence of eggs or proglottids (segments that make up the worms). Treatment – Anthelmintics can be used without apparent side effects in possums and gliders and include fenbendazole at a dose of 20–50 mg/kg PO s.i.d. for three days, oxfendazole at a dose of 5 mg/kg PO once only, and ivermectin at a dose of 200 ug/kg PO or subcutaneously once only (Booth 1999). Prevention – Good hygiene by the removal of faeces and quarantining of new animals. 8.3.3 Protozoans Cause –The protozoan parasite Toxoplasma gondii causes toxoplasmosis after the ingestion of felid faecal material containing sporulated oocysts (Rose 1999).

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Signs – Infection is often not apparent with clinical illness often occurring in animals that are immunosuppressed or hand reared (Rose 1999). The severity of the illness ranges from mild malaise to peracute mortality with other signs including depression, weakness, anorexia, pyrexia, dyspoeia, ataxia, hemiplegia, quadriplegia, coma, convulsions, muscle stiffness, diarrhoea, emesis, uveitis, retinitis or cataract formation (Rose 1999). Diagnosis – Antemortem diagnosis of toxoplasmosis is confirmed by serological testing to detect rising IgG Toxoplasma gondii titres. Direct Agglutination Test or Modified Agglutination Test using the commercial kit Antigene Toxo-AD and microtiter plate reagents (bioMerieux SA, Marcy l’Etoile, France) are useful (Rose 1999; Bettiol et al. 2000; Miller et al. 2000). Most commercial veterinary laboratories offer indirect haemagglutination inhibition tests for the detection of IgG. Indirect fluorescent antibody tests may be used to determine serum IgM concentrations (Rose 1999). Treatment – Drugs used to stop the replication of the parasite. Clindamycin is the drug of choice and is administered parenterally or orally at a dose rate of 10–15 mg/kg every night to 12 hours for as long as four weeks (Rose 1999). Sulfadiazine and pyrimethamine are used in combination to treat toxoplasmosis, sulfamethazine at 30–60 mg/kg PO every 12 hours and pyrimethamine 0.25–0.5 mg/kg PO every 12 hours. These drugs act synergistically to inhibit the synthesis of folinic acid, which is required by Toxoplasma gondii (Rose 1999). A folinic acid supplement will prevent the development of anaemia or leucopoenia by providing folinic acid 5.0 mg/day or brewers yeast 100 mg/kg/day (Rose 1999). Prevention – Prevention of access to cats and cat faecal matter is required. Cat faeces may contaminate bedding straw, sand or other substrates so cats should be excluded from storage areas (R. Booth pers. comm.). 8.3.4 Bacteria Cause – Yersinia pseudotuberculosis (Yersiniosis) has been confirmed as the cause of death of six Leadbeater’s possums at Melbourne Zoo, with typical lesions in a seventh. Lesions included multiple abcessation of the liver, spleen and kidneys with at risk animals being treated prophylactically with antibiotics (Booth 1994). Outbreaks of yersiniosis are thought to be associated with stress or immunosuppression (Rose 1999). Salmonella has been found in possums, however it seems to only target immunosuppressed or stressed individuals. Predisposing factors include overcrowding,

transportation, exposure to extended periods of cold conditions and young animals (Booth 1994). The yeast Cryptococcosis neoformans has been established as the cause of death in four Leadbeater’s possums in captivity. The lesions produced were meningoencephaltis and broncopneumonia (Booth 1994). Transmission is via inhalation of contaminated dust, and disease has been reported in a wide range of species. Infection generally occurs in immunosuppressed hosts and usually involves the central nervous system, nasal mucous membranes, lungs or skin (Booth 1994). Clinical signs include dilated pupils, head tilt, circling and uncoordination (Booth 1994). Mycobactium spp. and Leptospira spp. have also been found to be significant pathogens in possum species (Booth 1999). Signs – Although many animals will harbour Yersinia without affect, it is capable of causing multisystemic illness (Rose 1999). Yersiniosis results in either rapidly fatal enteritis or septicaemia or subacute to chronic multisystemic abscessation. Clinical signs of the rapid septicaemic form of the disease may include depression, dehydration, diarrhoea and melaena. Diagnosis – Yersinia is generally diagnosed by isolating organisms from within lesions. Yersinia can be difficult to isolate. However, cooling tissue samples briefly may increase the likelihood of isolating the organism (Rose 1999). Treatment – Usually treated with broad-spectrum antibiotics. Once clinical signs are apparent, animals may respond poorly to therapy (Rose 1999). Prevention – High standards of husbandry and hygiene are required and the protection of food and water from wild birds. Minimizing stress may also assist in its prevention (Rose 1999). 8.3.5 Fungus Cause – The fungus Candida albicans can result from antibiotic therapy causing candidiasis or thrush. It can also result from less than adequate hygiene or stress in hand-reared joeys (Blyde 1999; Woods 1999). Signs – Candida can result in diarrhoea that often has a foul yeast-like smell with a yellowish-green and sometimes frothy or curdled appearance (Woods 1999). With oral thrush it can result in the mouth becoming sore, ulcers and/or white plaques or crusting around the mouth and a rust coloured crusty discharge (Woods 1999). Diagnosis – Diagnosis is made through Gram stains of the faeces or oral cavity with high numbers of budding yeasts being used to confirm the diagnosis (Blyde 1999). The organisms are about half the size of a red blood cell

Possums and Gliders

and stain blue-purple (Woods 1999). It should be noted that Candida is normally present in the gastrointestinal tract of many marsupials in low numbers so the presence of yeasts in faecal smears does not necessarily indicate a problem (Blyde 1999; Woods 1999). Treatment – Can be given as Nilstat® Oral Drops (Wyeth Ayerst for Womens Health) or Mycostatin® Oral Drops (Bristol-Myers Squibb Pharmaceuticals) at 0.1–0.5 ml/kg orally three times per day over 3–5 days (Blyde 1999; Woods 1999). Failure of a candida associated diarrhoea to resolve using nystatin provides an alert to concurrent disease such as salmonellosis (Woods 1999). Prevention – Maintain high hygiene standards by frequently cleaning the possum so that excess milk formula or urine does not build up. It is also important to minimize stress, which reduces the animal’s ability to fight infection (Woods 1999). 8.3.6 Nutritional osteodystrophy Cause – Also known as hind limb paralysis, this condition is commonly reported in pet sugar gliders but has not been recorded in zoo collections (Booth 1999; pers. obs). It appears to be due to a calcium deficient diet that often includes only fruit and meat (Booth 1999; pers. obs). Nocturnal animals are presumed to rely on gut absorption of vitamin D3, rather than skin absorption of ultraviolet light to convert vitamin D1 to D3. Diets should contain approximately 1% calcium, 0.5% phosphorus and 1500 IU/kg of vitamin D3 on a dry weight basis (Booth 1999). Signs – Sudden onset of hind limb weakness or paralysis (Booth 1999). Diagnosis – Radiography of vertebral, pelvic, and long bones demonstrating osteoporosis. Spinal trauma is a differential diagnosis (Booth 1999). Treatment – Cases identified early may respond to a high calcium, additional vitamin D3 diet and strict cage rest (Booth 1999). Prevention – Hind-limb paralysis can be prevented by providing adequate calcium in the diet. Insects fed to gliders or pygmy-possums should be supplemented with calcium. Dusting insects with calcium powder is less reliable than feeding (gut loading) a high calcium diet 48 hours before they are fed out (Booth 1999). 8.3.7 Bloat Cause – Has been observed in common ringtail possums due to a build-up of gas in the gastrointestinal tract and has been recorded in both adult and juveniles. The intestines may twist and strangulate resulting in rapid death without surgical intervention (R. Booth pers. comm.).

Signs – The abdomen is extremely distended, feels tight and makes a drum sound when tapped (R. Booth pers. comm.). Diagnosis – Palpation and radiography (R. Booth pers. comm.). Treatment – Animals generally die. Surgery is potentially an option if they are caught in time. Early cases may respond to transabdominal removal of gas with a trocar and cannula (R. Booth pers. comm.). Prevention – Possible causes include poor diet and/or insufficient native browse (A. Gifford pers. comm.). Ensuring an appropriate diet and plenty of browse appears to be very important. 8.3.8 Alopecia Regular episodes of fur loss (alopecia) from September to January each year have been observed in female ground cuscus (Best 1998). This hair loss was characterized by a single rough, circular patch of bare skin on the dorsal surface of the trunk or lower neck. Each patch was located in an asymmetrical, rather than bilateral, position with respect to the animal’s midline. The skin where the hair loss occurred and the fur immediately adjacent to the bare area always appeared unaffected. Clinical examination of successive samples revealed no abnormalities (Best 1998). It was suggested that this fur loss may be the result of either seasonal hormonal or temperature changes.

9. Behaviour 9.1 Activity cycles Observations of captive sugar gliders with different light:dark lengths (L:D of 14:10, 12:12, 9:15) showed that although the amount of time utilized increased with increasing night length, the proportion of the night utilized decreased (Goldingay 1984). Activity within different night lengths increased from 9.7 hours at 14:10, to 10.3 hours at 12:12 to 18.8 hours at 9:15. The mean percentage of the night spent active decreased from 51.7% at 14:10, to 45.7% at 12:12, to 46.3% at 9:15. The peak period of activity was also shortly after the lights went out (Goldingay 1984). These results suggest that night:day lengths of 12:12, or slightly shorter nights, are preferable, although the change in day length may be important for initiating reproduction. The diet can also be important for the activity of possums and gliders, with the smaller possums (that are exudivore/insectivores) spending more time foraging, which increases with increasing body size up to the

227


Exudivore s

Folivore s

100

P. australis

80

% Time Feeding

228

P. norfolcensis 60

P. breviceps

P. gracilis

40

Ps. peregrinus Pe. volans

20

T. vulpecula

A. ursinus

0 4

5

6

7

8

9

10

Ln Body Mass (g) Figure 5. Relationship between body size, diet and proportion of night that different species of possums spend feeding. From Jackson and Johnson (2002). Note that Ailurops ursinus is the bear cuscus that occurs on Sulawesi.

largest exudivore (the yellow-bellied glider)(Fig. 5; Jackson and Johnson 2002). In contrast, the larger folivores spend less time feeding, and this reduces even further with as body size increases (Fig. 5; Jackson and Johnson 2002). Therefore, there are predictable limitations to the activity (and therefore visibility to the public) that can be achieved, even with activity feeds, when attempting to display possums and gliders in nocturnal houses. The thermoregulatory disadvantages of small size have been significantly reduced in the smaller members of the Petauridae and in all the Burramyidae, Acrobatidae and Tarsipedidae by the use of group huddling, nest construction (in tree hollows) and daily or seasonal torpor (Smith and Lee 1984). A number of authors have suggested torpor and hibernation as mechanisms to conserve energy and increase fasting endurance during poor weather, lower temperatures and during periods of food shortage (Wakefield 1970; Fleming 1980; Wooller et al. 1981; Renfree et al. 1984; Jones and Geiser 1992). Mountain pygmy-possums do not appear to enter hibernation unless their body mass reaches a certain level, which appears to be between 50 and 70 g (Fleming 1985a; Geiser et al. 1990). It is not known if seasonal hibernation in mountain pygmy-possums is regulated by a circannual rhythm, or changes in food availability, temperature or photoperiod (Geiser and Broome 1991). Wang (1989) described two types of torpor, one involving daily torpor with minimum body temperatures that are metabolically defended during torpor (11–28°C), and a second type that involves deep and prolonged torpor (hibernation) with minimum body temperatures (1–6°C) and torpor bouts lasting between one and three weeks. Larger species that undergo torpor

do so for only short periods while those of lower weights, except the honey possum, undergo periods of hibernation (Table 9). The honey possum may require torpor rather than hibernation because of the milder temperatures experienced in the areas where they are found in the south-west of Western Australia. Torpor is strongly air temperature dependent with higher temperatures resulting in significantly shorter bouts and a higher metabolic rate (Geiser and Broome 1993). During winter when temperatures fall they can be kept more active or even prevented from entering torpor by maintaining temperatures above approximately 12°C (Geiser and Broome 1993; L. Andrews pers. comm.). It is also worth noting that captive-bred feathertail gliders have been found to differ from wild gliders in behaviour (longer activity periods) and physiology (less frequent torpor, shorter torpor, shallower torpor, higher metabolic rates during rest and torpor, and slower rates of rewarming). Captive populations also often become hypothermic and are unable to rewarm (Geiser and Ferguson 2001). Mountain pygmy-possums also showed differences in behaviour and physiology between wild and captive animals. Wild possums fattened extensively during the pre-hibernation season, which was followed by seven months of torpor and hibernation, compared with captive-bred animals that neither fattened nor entered torpor in two consecutive winters (Geiser et al. 1990). Although torpor has been observed in mountain pygmy-possums in captivity (pers. obs.), it is likely that the artificial conditions in captivity do not provide the appropriate environmental cues for seasonal physiological alterations in this species (Geiser et al. 1990).

Possums and Gliders

Table 9. Weights and the occurrence of torpor or hibernation within the Australian members of the Phalangeroidea. Species

Weight (g)

Torpor/Hibernation

Ref.


100–166

Torpor?

1, 2

Petaurus breviceps

95–160

Torpor

1, 3

Burramys parvus

30–82

Hibernates

1, 4, 5


25–40

Hibernates?

1, 6

Cercartetus nanus

15–43

Hibernates

1, 7

Acrobates pygmaeus

10–14

Hibernates

1, 8, 9


8–20

Hibernates

1, 10

Tarsipes rostratus

7–12

Torpor

1, 11

Cercartetus lepidus

6–9

Hibernates

1, 10

References: 1 Strahan 1995; 2 Smith 1980; 3 Fleming 1980; 4 Fleming 1985a; 5 Geiser and Broome 1991; 6 Atherton and Haffenden 1982; 7 Geiser 1993; 8 Fleming 1985b; 9 Jones and Geiser 1992; 10 Geiser 1987; 11 Withers et al. 1990.

9.2 Social behaviour 9.2.1 Honey possum Russell (1986) has made extensive observations of the behaviour of honey possums in captivity. Little is known about their dispersal, mating system or social organisation in the wild, though they are considered to be polyandrous and nest in groups (Wooller et al. 2000). A hierarchy exists with females, which are larger than males, appearing to show dominance over non-breeding females and males, by excluding others from food. Although aggressive encounters are uncommon, they have a range of aggressive agonistic behaviours including pawing, snout jabbing, lunging, jump attacks, chasing and wrestling (Russell 1986). 9.2.2 Feathertail glider Feathertail gliders appear to live in groups of up to 29, though two to five is normal. The groups usually consist of adults with the offspring of one or two litters (Fleming and Frey 1984; Ward 1990a; Strahan 1995). They generally show fidelity to one or two nests and the use of the same nest by other individuals is tolerated, suggesting they are polygynous (Fleming and Frey 1984). Breeding appears to occur best when animals are held in relatively large enclosures that contain a number of animals rather than in pairs (Woodside 1995). Their nest sharing, the presence of reproductive females with several males, and the little evidence of prolonged associations between males and females suggests they are promiscuous (Fleming and Frey 1984; Ward 1990a). 9.2.3 Pygmy-possums In the wild, they are normally solitary, especially during the breeding season (Ward 1990b, 1990c). The lack of prolonged associations between the sexes led to the conclusion that they are promiscuous (Ward 1990b,

1990c). In captivity, they generally appear to be socially tolerant with nest boxes readily shared, and males showing low levels of aggression even in the presence of females (eg Kerle 1984a). Other observations found that despite a number of nest boxes being available, individuals were most often nesting with others of the opposite or same sex, and only occasionally were individuals nesting on their own (Andrews 2003). Observations of wild long-tailed pygmy-possums showed that they build nests beneath the dead fronds of pandanus palms and in tree hollows (Dwyer 1977). The nests, which are spherical in shape, are constructed of dead leaves attached to stems and may be up to 15 cm in diameter and within a few metres of the ground. Adult females with regressing teats have been found together or with males in the same nest, however there are no other observations of adult or subadult individuals of either sex being found together with a lactating female (Dwyer 1977). Eastern pygmy-possums appear to be largely solitary, with individuals nesting either alone or with a female and young (Ward 1990b). One study of nest occupancy found solitary animals on 71.4% of occasions, lactating female with young on 20%, and only 8.6% having more than one independent individual. None of these groups contained a lactating female or more than one adult female, while four contained more than one adult male (Ward 1990b). In captivity, eastern pygmy-possums have been known to routinely share nest boxes with members of the same and opposite sex (L. Andrews pers. comm.). Female mountain pygmy-possums are usually sedentary and occupy food and shelter rich habitats both during and outside the breeding season, whereas males are often forced into habitat, at lower elevations, containing poorer resources (Mansergh and Scotts 1990). So, the males visit the female habitats during the breeding season and return to less favourable habitat

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afterwards (Mansergh and Scotts 1989; Mansergh and Broome 1994). A nest discovered in the wild in a granite boulderfield (buried by a layer of soil), was 15-20 cm in diameter and consisted of long, clean strands of moss (Brachythecium salebrosum) with a few blades of grass (Poa sp.) intertwined, which kept the possums dry while the surrounding soil was damp (Heinze and Olejniczak 2000). In captivity they generally appear to be socially tolerant and commonly share nest boxes, however aggression was observed when a new male was placed with an established pair, resulting in the resident male chasing the outsider (Arlidge et al. 1993; Kerle 1984a). The general high level of social tolerance is suggested to be advantageous in allowing huddling, which reduces heat loss (Fleming 1985a). Breeding females appear to defend their nest boxes. When a large number of males and females were placed together at Healesville Sanctuary (resulting in successful matings) the males inhabited nest boxes on the edge of their large enclosure. This appears to mimic the wild situation with the segregation of the sexes during the non-breeding season and the males traversing up the mountain in spring in order to mate (Mansergh and Walsh 1983; Mansergh et al. 1988). 9.2.4 Petaurids Little information is available on the social behaviour of the striped possum. Den sharing has been observed on several occasions in the wild in New Guinea, however observations in Australia suggest they rarely share dens and are more solitary than other petaurids (Hide et al. 1984; K. Handasyde pers. comm.). In one case in the wild, there was intense raucous rivalry between two males over an oestrous female, with all three producing continuous, rolling, guttural shrieks (Van Dyck 1995). They are also known to produce several vocalizations (Handasyde and Martin 1996; Carmichael 2000). As with other petaurids, scent marking plays an important role in the social life of the striped possum. They have an anal gland that exudes a very strong musty odour that is rubbed onto branches by the animal performing a cloacal drag (Biggins 1984; Carmichael 2000). Upon meeting, they raise their tails over and parallel to their backs with the fur on the tail standing on end and they may move their tails from side to side (Carmichael 2000). Leadbeater’s possums are monogamous in captivity with cohesion in the group being maintained by the dominant breeding pair spreading salivary odours during extensive grooming in the nest and mutual licking of the tail-base (Smith 1995a). Other behaviours include a chatter challenge call, attacking each other, grappling, sniffing and an alarm hiss when held against their will.

Colonies in the wild have been observed to contain a single adult female with one to three adult males, suggesting they are monogamous or polyandrous (Smith 1980). Females are more socially aggressive than males and readily attack and pursue animals of either sex from another colony (Smith 1995a). Similar observations in captivity suggest that captive colonies do not like the introduction of females and will fiercely attack them. Juvenile females should also be removed prior to sexual maturity to avoid being attacked. Yellow-bellied gliders live in family groups, generally of three to six individuals, but there may be up to eight (mean 2.6), comprising a male with one or two females and their offspring (Craig 1985; Goldingay and Kavanagh 1990; Goldingay et al. 2001). They can be monogamous, polygynous or even swap between the two depending on resource availability (Henry and Craig 1984; Craig 1985; Goldingay and Kavanagh 1990; Goldingay and Kavanagh 1991; Goldingay et al. 2001). Although all the petaurids make various calls, the yellow-bellied glider is by far the most vocal, having an extensive vocal repertoire and making numerous different calls throughout the night (Kavanagh and Rohan-Jones 1982; Goldingay and Kavanagh 1991; Goldingay 1994). As with all members of the genus Petaurus, the male has a well developed scent gland on the top of his head that is used to mark other members of the group. Other glands on the chest and the underside of the tail are also used to mark their territory and each other (Russell 1995). When gliders are held in a colony, members are regularly scent-marked by mature males and animals not bearing this scent are often attacked (Dunn 1982). Therefore, the introduction of unfamiliar animals into these groups should be attempted with great caution. The sugar glider is generally considered to be polygynous in the wild with colonies of two to seven (Henry and Suckling 1984; Suckling 1984; Quin 1995; Sadler and Ward 1999). In captive populations however, only one adult male in the colony is reproductively active, with the colony consisting of a monogamous pair, offspring and occasionally unrelated adult males (Bradley and Stoddart 1993; Mallick et al. 1994; Stoddart et al. 1994; Klettenheimer et al. 1997). Field-based studies by Sadler and Ward (1999) found clear evidence that sugar gliders are polygynous and the associations between adult males and their putative sons by Klettenheimer et al. (1997) were artefacts of captivity. Observations of the mahogany glider suggest they are territorial and live in pairs with home ranges that almost entirely overlap (86% compared with only approximately 11% with other males and females). An indication of

Possums and Gliders

their territorial behaviour was observed when a male glider viciously attacked a second glider (thought to be a male) and also by their foraging loops where they appear to cover the boundary of the home range every few nights (Jackson 2000b). The frequent den sharing and high degree of home range overlap suggests they are socially monogamous, though males have been observed to mate with the non-paired mate, indicating that extra-pair matings do occur (Van Dyck 1993; Jackson 2000b). Squirrel gliders live communally in groups of between two and nine individuals, with at least one male and several females, suggesting a polygynous mating system (Quin 1995). A family group typically comprises one mature male (more than two years old), and one or more adult females and their offspring (Suckling 1995). Up to two adult males may be present in a nest (with a single male more than three years old)(van der Ree 2002). The presence of multiple adult males of both sexes within a social group suggests the mating system is polygamous or polygynous (van der Ree 2002). Scent marking glands on the head are well developed (Suckling 1995). 9.2.5 Ringtail possums and greater glider Adult common ringtail possums regularly share hollows and/or dreys in a variety of combinations (Thomson and Owen 1964). Observations of common ringtail possums in the wild found most males (60%) associated with only one female at a time and this bond lasted through the breeding season, although they ‘sneaky breed’ with other females, suggesting a socially or facultative monogamous mating system. A few males that were generally older and larger associated with two females throughout the breeding season, suggesting polygyny (Ong 1994). Although ringtail possums are largely solitary, males actively initiate and maintain contact with females by constantly visiting their mates, at least once per night, throughout the year and more frequently during the breeding season and actively defend their mates from other males (Ong 1994). Captive observations have shown that a juvenile male viciously attacked a smaller unrelated female (Presidente 1982b), and a castrated male has been observed to attack other males and females (L. Andrews pers. comm.). Observations of captive and wild western ringtail possums suggest that adults do not share nest sites (nest boxes or dreys). Captive females do not tolerate adult males, although males rarely initiated agonistic behaviour (Ellis and Jones 1992). Adult females shared their nest boxes with their young until the pouch young were approximately 90 days old and nearly ready to emerge from the pouch for the first time. At this time the

older young was evicted from the nest box (Ellis and Jones 1992). Rock ringtail possums appear to live in family groups of a male, female and any offspring, in mutually exclusive home ranges. Observations suggest that males and females contribute equally to parental care and maintain the pair bond and nest by using scent marking (Runcie 2000). As a result of these observations the mating system in the rock ringtail possum is suggested to be obligate social monogamy (Runcie 2000). Little information is available on the social behaviour of the rainforest ringtails. Lemuroid ringtail possums have been observed to be by themselves on 64% of occasions, with green ringtails (94%) and Herbert River Ringtails generally being found by themselves (Winter and Atherton 1984). When these species were found in groups, which consisted of two or three, they were thought to comprise an adult male and female and/or a female with young (Winter and Atherton 1984). Greater gliders are largely solitary and in high densities in the wild the home ranges of males and females have often been found to overlap, indicating a polygamous mating system (Comport et al. 1996). In other low-density populations they have been found to have exclusive home ranges and males are able to maintain sole access to one or more females indicating a facultative monogamous mating system (Henry 1984). 9.2.6 Cuscuses, brushtail possums and scaly-tailed possum Common brushtail possums are highly territorial, polygynous, have a dominance hierarchy and often show aggression towards each other, particularly dominant males toward subordinate males (Biggins and Overstreet 1978). Females and males appear to mate with several mates and are likely to have a serial polygyny mating system (Lee and Cockburn 1985; Taggart et al. 1998). The mountain brushtail possum appears to be socially monogamous, forming strong pair bonds with pairs having home ranges that overlap by approximately 80%, remaining in close proximity to each other and their dens during the night (Martin et al. 2001). Genetic analysis of wild populations also suggests that most offspring are fathered by the socially paired mate (Martin et al. 2001). Communication by scent and sound includes well-developed chin, chest and anal glands and a range of vocalizations (How and Kerle 1995). Removing the dominant male for a short time does not appear to produce any significant changes in the dominance hierarchy of the rest of the group and the dominant male will readily reassert his dominance once he returns.

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When new animals are introduced into the group they generally occupy a low position in the hierarchy (Biggins and Overstreet 1978). Yearling females with their first pouch young are generally defensive and frequently keep to themselves, while mature females with young in the pouch or on their backs often get on well together (Presidente 1982a). Very little is known of the social behaviour of scaly-tailed possums except that they appear to have a number of dens and be largely solitary (Runcie 1999). Both sexes also appear to lack sternal and paracloacal glands, which are well developed in brushtail possums. The social behaviour of the various species of cuscus is also poorly known, however they are generally considered to be solitary. Males (eg spotted cuscus) are aggressive towards each other in captivity and cannot be housed together (Winter and Leung 1995).

9.3 Reproductive behaviour Courtship behaviour is not well understood for most species. The copulatory behaviour of the mahogany glider has been described (Van Dyck 1993). During this event, the male produced a soft ‘chew-chew-chew-chew’ at which the female made immediate efforts to join him. The female sniffed the male’s rump and then followed him up the tree to rest with him in the canopy. The two glided to a nearby tree where they curled up around one another. The male then lunged at the female and they copulated for approximately 23 minutes, during which time they both adopted a vertical head-down position on the trunk, with the male thrusting intermittedly. The male grasped the female’s dorsum in a similar fashion to that adopted by young back riding gliders newly emerged from the pouch and he bit her neck until they separated (Van Dyck 1993). Similar behaviour has been observed with brushtail possums, although they are a lot noisier.

9.4 Bathing Bathing is not normally observed in any of the possums and gliders.

9.5 Behavioural problems The different groups of possums and gliders appear to suffer little from behavioural problems.

9.6 Signs of stress Acute stress can be associated with loud vocalizations, threats and attacks or excess urination or defecation (Spielman 1994). Ringtail possums for example may launch themselves at a person while cuscus and brushtail possums can threaten and attack fiercely (Spielman 1994).

9.7 Behavioural enrichment Behavioural enrichment activities for possums and gliders can include: ■

■

■

■

■

■

■

Providing browse such as leaves, flowers or gums (see Section 6) Providing live food, such as mealworms or crickets, for insectivorous species as activity feeds at times throughout the day Placing food on branches (fruit spiked on branches) throughout the enclosure rather than in the one location in a feed tray Providing nesting material such as stringybark to promote nest building behaviour Providing those that are able with opportunities for gliding Housing them with other terrestrial species as appropriate Providing gums (Gum Arabic Powder food grade by Swift Ltd) in gum feeders for species that feed on them such as the Petaurus gliders (Hawkins 1999); feeding gums to Leadbeater’s possums has resulted in diarrhoea (Lynch 1995).

9.8 Introductions and removals Most introductions and removals can be undertaken with few problems. Some of the more social species, such as the petaurids, which live in family groups and who use scent to maintain the group structure, may need to be carefully observed to assess if there are any problems of aggression. Larger species such as the brushtail possums can be very aggressive towards each other so they also need to be carefully monitored to assess the level of aggression.

9.9 Intraspecific compatibility The social structure and mating system are influenced by several factors, including body size (smaller species often huddle together when it is cold to minimize heat loss), diet and its availability, and competition between individuals. In some species of mammals that have more than one mating system, it is generally the result of the males’ ability to defend females and/or resources. Polygyny is favoured when: ■

■ ■

Food resources are concentrated (Emlen and Oring 1977) Males can defend access to more than one female or Females do not require males to raise offspring (Emlen and Oring 1977; Kleiman 1977).

Monogamy is favoured when the reverse of the above is true.

Possums and Gliders

Table 10. Social structure and mating system of different genera of possums and gliders when held in captivity. Families are listed in order of approximately increasing body size. Genus

Social Structure

Mating System

Suggested Sex Ratio

Ref.

Tarsipedidae Tarsipes

Colonial

Polyandrous

3:5

1

Acrobatidae Acrobates

Colonial

Promiscuous

1:1–10:10

2, 3

Burramyidae Burramys Cercartetus

Colonial? Solitary

Polygamous Promiscuous

1:1–5:5 1:1–5:5

4

Petauridae Dactylopsila Gymnobelideus Petaurus

Solitary/Pairs Colonial/Pairs Colonial/Pairs

Polygamous? Monogamous Monogamous/Polygamous

Solitary or 1:1 Solitary or 1:1 Solitary or 1:1

5 6, 7 8, 9, 10, 11, 12

Pseudocheiridae Hemibelideus Petauroides

Solitary? Solitary

Solitary or 1:1 Solitary or 1:1

13, 14, 15

Petropseudes Pseudocheirus Pseudochirops Pseudochirulus

Solitary/Pairs Solitary/Pairs Solitary/Pairs Solitary/Pairs

Monogamous? Polygamous/Monogamous/ Polygynous Monogamous Monogamous/Polygamous Monogamous? Monogamous?

Solitary or 1:1 Solitary or 1:1 Solitary or 1:1 Solitary or 1:1

16 17, 18, 19 20 20

Phalangeridae Phalanger Spilocuscus Trichosurus Wyulda

Solitary/Pairs? Solitary/Pairs? Pair/Solitary? Solitary

Monogamous? Monogamous? Monogamous/Polygamous Monogamous?

Solitary or 1:1 Solitary or 1:1 Solitary or 1:1 Solitary or 1:1

21, 22 23

References: 1 Wooller et al. 2000; 2 Fleming and Frey 1984; 3 Ward 1990a; 4 Ward 1988; 5 Carmichael 2000; 6 Smith 1980; 7 Smith 1984b; 8 Henry and Craig 1984; 9 Henry and Suckling 1984; 10 Suckling 1984; 11 Craig 1985; 12 Jackson 2000b; 13 Henry 1984; 14 Henry 1985; 15 Comport et al. 1996; 16 Runcie 2000; 17 How et al. 1984; 18 Pahl 1987b; 19 Pahl and Lee 1988; 20 Winter and Atherton 1984; 21 How 1976; 22 How 1981; 23 Runcie 1999.

Therefore, in a captive environment with plenty of food, species that do at times practise polygyny in the wild should readily be able to exhibit it in captivity due to the ample food requirements and lack of competition (as they are usually housed in groups of one male and one or more females). Most of the smaller species of possums and gliders can readily be held together, however as a general rule the larger species are more solitary and aggressive. Therefore, males of species such as brushtail possums and cuscuses should never be housed together and invariably both sexes are held separately or as pairs to avoid or minimize aggression. The mating system for the different genera of possums and gliders is shown in Table 10.

9.10 Interspecific compatibility Generally, the smaller species of possums in the families Tarsipedidae, Acrobatidae and Burramyidae have been

held by themselves as they are normally kept in small enclosures for ease of viewing by the public, or for off exhibit maintenance. There is one record of eastern pygmy-possums being introduced to feathertail gliders, and immediately evicting the gliders from one of their nest boxes; however no further interspecific fighting was observed (Pepper-Edwards 1988). A number of the larger possums and gliders in the families Phalangeridae, Petauridae and Pseudocheiridae have been held with other species in captivity. As these species are generally arboreal and require larger exhibits, a number of terrestrial species can be held with them. These include short-beaked echidna Tachyglossus aculeatus, long-beaked echidna Zaglossus bruijnii, long-nosed bandicoots Perameles nasuta, eastern-barred bandicoots Perameles gunnii, long-nosed bandicoots Perameles nasuta, long-footed potoroos Potorous longipes, long-nosed potoroos Potorous tridactylus and

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brush-tailed bettongs Bettongia penicillata. Nocturnal birds such as nightjars and tawny frogmouths are generally not recommended to be housed with these species as there is likely to be aggression between them that may involve the birds being preyed upon. For example, squirrel gliders have been known to attack and kill Australian magpie-larks Grallina cyanolueca and halfgrown guinea-fowl Numida meleagris, while sugar gliders have been known to kill mice Mus musculus in captivity (Troughton 1941; Fleay 1954). Several species of possums and gliders have been held together including yellow-bellied gliders, with Leadbeater’s possums and greater gliders. Leadbeater’s possums have been housed successfully with ringtail possums, while brushtail possums have lived with tawny frogmouths Podargus strigoides (A. Gifford pers. comm.). Yellow-bellied gliders have also been held with grey-headed fruit bats Pteropus poliocephalus, which generally worked well, although there was occasional fighting between individuals over food (which frequently occurs in the wild eg pers. obs., Borsboom 1982). Some species of possums such as the mountain brushtail, common brushtail and cuscuses are generally housed by themselves due to their aggressive natures.

10. Breeding 10.1 Mating system The mating system varies between species and is dependent on factors such as body size and food availability (see Section 9.1). The mating system for species where it is known is shown in Table 10.

10.2 Ease of breeding 10.2.1 Honey possum Until recently, the honey possum has not bred well in captivity, however the use of a high nitrogen diet and large outdoor, natural-type enclosures appears to have resulted in more consistent breeding (Bradshaw et al. 2000). 10.2.2 Feathertail glider The feathertail glider breeds well at Taronga Zoo in large indoor enclosures, however it has not bred very well anywhere else. The trigger appears to be having large enclosures with a large number of animals, ie more than 12–15. They then appear to breed until they reach the carrying capacity of the enclosure and then, either breeding is reduced or natural mortality increases.

10.2.3 Pygmy-possums The eastern pygmy-possum has been held in captivity the most often and there has been little success breeding them until recently. In the past pygmy-possums have been placed in small enclosures, where they have lived well but not bred well. Recently Healesville Sanctuary has been successful in breeding them consistently by placing them in a large double meshed enclosure (10 × 5 × 3.3 m high) that was heavily planted with native grasses and flowering shrubs (Andrews 2003; Murphy et al. 2003). Under these conditions, over 30 pygmy-possums have been born over a five-year period (Andrews 2003). The mountain pygmy-possum has bred well from wild caught females, however first generation females invariably fail to breed. Captive-bred mountain pygmy-possums lack the seasonal changes in physiology exhibited by wild animals and generally do not increase body mass to the extent of wild-caught animals (Geiser et al. 1990). In the wild, the breeding period has been associated with 1) the spring equinox; 2) the arrival of the bogong moths; 3) arrival of males in female habitat and final emergence from hibernation, and 4) the loss of the snow cover at the end of the winter (Mansergh and Scotts 1990; Kortner and Geiser 1996). In captivity at Healesville Sanctuary a number of mountain pygmy-possums bred after being removed from refrigerators to a large outdoor enclosure where they were housed in a large group (of approximately equal sex ratio), subsequently breeding has been sporadic and it is not known if captive-born young have successfully bred. Therefore, it is not known if the refrigeration, large group size or the change to natural conditions resulted in the high initial breeding success. 10.2.4 Petaurids The smaller gliders, such as the sugar and squirrel gliders, generally breed well in captivity. Several hand-reared mahogany gliders, of which one was extraordinarily obese, have been held in captivity and have subsequently bred so it is likely they can breed well. The lack of success with breeding yellow-bellied gliders may be due to the small numbers held in captivity, their proneness to obesity and the fact that they have frequently been maintained in captivity after hand-rearing. Leadbeater’s possums generally breed relatively well as part of their international studbook, however individuals within the longstanding breeding program stopped breeding, so further recruitment from the wild was required. The halt in breeding may be due to increased inbreeding or other unknown factors.

Possums and Gliders

Striped possums have not bred well in captivity over the years, which has contributed to their poor representation in captive institutions. However, in 1999 London Zoo were successful in breeding them (F. Wheeler and A. McKenna pers. comm.). 10.2.5 Ringtail possums and greater glider The ringtail possums have not bred well in captivity, however this is possibly because institutions have not wanted to breed them as they are frequently handed into zoos or shelters and hand-reared. Greater gliders have bred very poorly in zoos, which may be due to the low numbers being brought into captivity. 10.2.6 Cuscuses, brushtail possums and scaly-tailed possum Cuscus have bred several times in captivity, however there are few records. Brushtail possums can breed well in captivity, however most institutions do not attempt to breed them due to their territorial nature, which means the offspring need to be removed upon maturity, and the difficulty in finding other institutions that will take them. The scaly-tailed possum has only been held in captivity for a relatively short period and has not had the opportunity to breed.

10.3 Reproductive status 10.3.1 Females Possums and gliders are generally placed in several categories depending on their reproductive status. The examination of reproductive status in medium to large species can be facilitated by putting them inside a transparent plastic tube and examining the pouch with an otoscope (Roberts and Kohn 1991). For females the categories are: ■

■

■

■ ■

Non-parous (females that have never bred) – pouch small with no skin folds, clean and dry, teats very small Parous (females that have bred previously but not presently) – pouch is small but distinct, dry and dirty, the teats are slightly elongated Pregnant – pouch is pink in colour and glandular in appearance, skin folds may be observed on the lateral margins Pouch young present – attached to the teat Lactating (young absent from the pouch but still suckling) – pouch area large, skin folds flaccid, hair

■

sparse and stained, skin smooth and dark pink, teats elongated Post lactation with teats expressing only clear liquid and/or regressing

If pouch young are present there are a number of developmental stages and measurements that can be recorded and compared to existing growth curves (See Section 10.16), or used to establish curves for future reference. These include: Developmental stages ■ Sex distinguishable ■ Tips of ears free ■ Papillae of facial vibrissae evident ■ Eyelashes visible ■ Eyes open ■ Fur visible – slight tinge, medium or well developed ■ Tips of first incisors through the gums ■ On back or in nest ■ Eating solids ■ Self feeding ■ Independent Measurements – (see Appendix 5) ■ Weight (g) – if not on teat ■ Head length (mm) – from the occiput to snout tip ■ Head width (mm) – maximum width across the zygomatic arches ■ Crown rump length (mm) – primarily for very small neonates ■ Body length (mm) – from snout tip to cloaca ■ Tail length (mm) – from the cloaca to the end of the last vertebra of the tail tip ■ Total length (mm) – from snout tip to tail tip ■ Tibia length (mm) – from the hip to the bottom of the pes ■ Pes length (mm) – from the heel to the base of the longest toe, not including the claw 10.3.2 Males In some species, such as the Petaurus gliders, the males have a scent gland in the middle of their forehead and on the sternum (also found in brushtail possums) that becomes increasingly developed with age. The activity of the gland can be measured from the following scale (Millis and Bradley 2001): 1. Little or no activity – little or no staining of the surrounding hair; little or no hair loss over the gland area; no obvious gland product 2. Medium level activity – some staining of the surrounding hair; some loss of hair over the gland area; waxy glandular products visible

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3. High activity – much staining of the surrounding hair; total loss over gland area; waxy glandular product prominent. In males of seasonally breeding species, the testes can increase in size during the breeding season. The testes should be measured by measuring the length, width and depth in millimetres. Testis volume can be calculated by using the equation V= π/6 × (length) × (width)2 (Spencer 1996).

10.4 Techniques used to control breeding The altered day/night lengths that result from maintaining possums and gliders for public display is likely to affect their breeding. In a group of brushtail possums moved from an outside enclosure to a room with a 10 h light and 14 h dark cycle, the possums indoors gave birth after 81 days compared with 134 days for the control group outdoors (Gemmell 1990). This suggests that photoperiod plays an important role in the initiation of breeding in the brushtail possum (Gemmell 1990). In further experiments on day length, brushtail possums were held in enclosures with a short day length (10 h light: 14 h dark) and long day length (14 h light: 10 h dark) (Gemmell and Sernia 1992). These resulted in the possums in the short day length enclosures breeding earlier in the year (12 Jan to 14 Feb) than the long day length possums (5 May to 8 August), with the possums in natural light giving birth from 3 March to 8 May (Gemmel and Sernia 1992). Over a two-year period the possums in both long and short day length conditions bred three times and those in natural lighting bred twice (Gemmell et al. 1993).

10.5 Occurrence of hybrids To date, there have been few hybrids between different species of possums. A female Victorian sugar glider and a male Queensland squirrel glider have produced a fertile hybrid (Fleay 1947). Zuckerman (1953) also reported a hybrid between a sugar glider and a squirrel glider.

10.6 Timing of breeding There is a large variation in the start and duration of breeding in the possums and gliders depending on the season and food availability. Breeding can be seasonal or continuous (Table 11).

10.7 Age at first and last breeding There is a large variation in the range of first and last breeding in the possums and gliders, with first breeding ranging from less than five months in the

pygmy-possums to approximately 36 months for the mountain brushtail possum. Breeding generally continues until death (Table 11). Oestrus can be determined by examining the urine for the presence of non-keratinised and keratinised epithelial cells, polymorpho-nuclear leucocytes and sperm (Duckworth et al. 1998). At the time of oestrus, there is a massive increase in the number of epithelial cells and leucocytes in the urine. In most species it is thought that the females can breed up until their death, however in the mountain brushtail possum records suggest that females show reproductive senescence prior to their death (Viggers and Lindenmayer 2000). They have been found not to successfully rear young after the age of approximately nine years, even though there are records of them living as long as 17 years (Lindenmayer et al. 1991; Viggers and Lindenmayer 2000).

10.8 Ability to breed every year All species of possums and gliders appear to be able to breed at least once per year.

10.9 Ability to breed more than once per year Most species of possums and gliders produce one or two litters per year (Table 11). Several species of possums have been observed to breed more often in captivity than they do in the wild. Ringtail possums have been observed to wean young earlier in captivity than in the wild (160 days vs 180–220 days respectively), reach maturity earlier (11 months vs 13 months), breed throughout the year and produce up to three litters per year (instead of one or two) (Thomson and Owen 1964; How et al. 1984; Roberts et al. 1990). Similar observations of higher fecundity in captivity have also been observed for the sugar glider, which can also produce three litters per year (MacPherson 1997).

10.10 Nesting requirements Most species require a nest box, even if they do not generally use tree hollows in the wild. Nesting material, which can include fresh branches of eucalypts, casuarina and leptospermum, should also be supplied so the leaves can be used (eg pygmy-possums, ringtails, petaurids). Branches of stringybark should be provided for some species (eg Leadbeater’s possum) so they can use the bark. Other material that has been used includes sea grass, fine dry grasses that are commercially available, hay and shredded paper, though these are generally

Possums and Gliders

Table 11. Reproduction and development of possums and gliders. Species

Birth Season

Litter Size (mean)

Litters/ Year

Permanent pouch exit (days)

Weaning (days)

Sexual Maturity (months) M

F

Ref.

Burramyidae Burramys parvus

Oct–Nov

1–4 (4)

1

33–37

70–75

12

12?

1, 2, 3, 4


Aug–Feb

1–4

–

34–45

92

15

–

4, 5


All year

3–6

2–3

25–30

50

12–15

–

4, 6, 7, 8, 9, 10

Cercartetus lepidus

Sep–Jan

2–4

–

–

90

–

–

1

Cercartetus nanus

Sep–Apr

2–6 (4)

2–3

30–42

50–65

4.5–5

4.5–5

11, 12

Petauridae Dactylopsila trivirgata

Mar–Jun

1–2

1

–

–

–

–

13, 14


May–Jun Oct–Nov

1–2 (1.5)

2

80–93

110–120

12

–

4, 15

Petaurus australis

Nov–May

1

1

90–100

180–240

24

18

4, 16, 17, 18, 19

Petaurus breviceps

Apr–Nov

1–2 (1.8)

1–2

70–74

110–120

8–15

12

4, 20, 21, 22, 23, 24

Petaurus gracilis

Apr–Sep

1–2 (1.6)

1

–

–

12

12

24

Petaurus norfolcensis

May–Dec

1–2 (1.7)

1

–

–

12

12

25, 26, 27


Aug–Nov

1

–

–

–

–

–

4

Petauroides volans

Mar–Jun

1

1

90–120

180–210

12+

12+

4, 28, 29, 30

Petropseudes dahli

Mar–Aug

1

–

–

–

–

–

4

Pseudochirops archeri

Aug–Nov

1

–

–

–

–

–

4

Pseudochirulus cinereus

All Year?

1

1

–

–

–

–

4

Pseudochirulus herbertensis

All year?

1

1

120

150–160

16

–

4, 31

Pseudocheirus occidentalis

Apr–Nov

1–2

1

104

–

10–11

–

32, 33

Pseudocheirus peregrinus

Apr–Nov

1–4 (2)

1–2

120

150–240

12

10–12

34, 35, 36, 37, 38

All year

2–4 (2.5)

2+

63–70

90

6

–

39, 40, 41

All year/ Seasonal

2–4 (2.5)

2

50–65

90–100

6–8

12

4, 42, 43, 44

Phalanger intercastellanus

Jun–Sep

2

1

–

–

–

–

4

Spilocuscus maculatus

Jun?

1–3 (1)

1

–

–

–

–

4

Trichosurus caninus

Mar–May

1

1

150–200

275

22–36

36

45, 46, 47

Trichosurus vulpecula

Mar–Nov

1

1–2

140–150

230

12–24

24

48, 49, 50, 51, 52, 53


Mar–Aug

1

1

150–200

>240

24

>18

4, 54, 55

Pseudocheiridae

Tarsipedidae Tarsipes rostratus Acrobatidae Acrobates pygmaeus

Phalangeridae

References: 1 Dimpel and Calaby 1972; 2 Kerle 1984b; 3 Mansergh and Scotts 1990; 4 Strahan 1995; 5 Atherton and Haffenden 1982; 6 Bowley 1939; 7 Casanova 1958; 8 Clark 1967; 9 Ward 1990c; 10 Ward 1992; 11 Turner 1983; 12 Ward 1990b; 13 Handasyde and Martin 1996; 14 Handasyde et al. 2001; 15 Smith 1984b; 16 Russell 1983; 17 Russell 1984; 18 Craig 1985; 19 Goldingay 1992; 20 Smith 1971; 21 Smith 1973; 22 Smith 1979; 23 Suckling 1984; 24 Jackson 2000a; 25 Quin 1995; 26 Millis and Bradley 2001; 27 van der Ree 2002; 28 Smith 1969; 29 Tyndale-Biscoe and Smith 1969; 30 Henry 1984; 31 Haffenden 1984; 32 Ellis and Jones 1992; 33 Jones et al. 1994; 34 Thomson and Owen 1964; 35 Hughes et al. 1965; 36 How et al. 1984; 37 Pahl and Lee 1988; 38 Ong 1994; 39 Renfree 1980; 40 Wooller et al. 1981; 41 Renfree et al. 1984; 42 Fleming and Frey 1984; 43 Ward and Renfree 1988; 44 Ward 1990a; 45 Smith 1973; 46 How 1976; 47 How 1981; 48 Lyne and Verhagen 1957; 49 Dunnet 1964; 50 Smith et al. 1969; 51 Crawley 1973; 52 Smith and How 1973; 53 How 1976; 54 Humphreys et al. 1984; 55 Runcie 1999.

237

238


Table 12. Duration of oestrous cycle and gestation for a number of possums and gliders. Species

Oestrous Cycle (days)

Gestation (days)

Post-partum oestrus

Embryonic Diapause

Ref.

Burramys parvus

–

13–16

–

–

1


–

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