Sneak preview of A Guide to Australian Skinks in Captivity by ABK/Reptile Publications and Australian BirdKeeper

A Guide to…

Australian

SKINKS in Captivity SNEAK PREVIEW

By Dr Danny Brown

BVSc (Hons) BSc (Hons)

CONTENTS ABOUT THE AUTHOR ....................................................................................................................................16 ACKNOWLEDGMENTS ......................................................................................................................................................17

INTRODUCTION ...............................................................................................................................................................19 GENERAL MANAGEMENT.............................................................................................................20 PET SUITABILITY ...........................................................................................................................................................................................20 CHOOSING YOUR STOCK ...............................................................................................................................................................20 Selecting an Individual Lizard ...................................................................................................................................................21 HANDLING AND HYGIENE ...........................................................................................................................................................22 TRANSPORTATION ....................................................................................................................................................................................24 Short Journeys.....................................................................................................................................................................................................24 Long Journeys ......................................................................................................................................................................................................25 Timber Boxes..........................................................................................................................................................................................................26 Plastic Containers ...........................................................................................................................................................................................27 PURCHASE AND FREIGHT ETIQUETTE ..................................................................................................................27 Buyers ................................................................................................................................................................................................................................27 Sellers .................................................................................................................................................................................................................................28 LEGAL REQUIREMENTS ....................................................................................................................................................................29 GENERAL SAFETY........................................................................................................................................................................................30 SECURITY....................................................................................................................................................................................................................31 QUARANTINE ......................................................................................................................................................................................................32

HOUSING INDOOR ENCLOSURES ..................................................................................................................................................32

Rack Systems ..........................................................................................................................................................................................................32 Tubs .......................................................................................................................................................................................................................................32 Tanks ....................................................................................................................................................................................................................................33 Pits ...........................................................................................................................................................................................................................................34 Timber Enclosures .........................................................................................................................................................................................34 Glass, Perspex or Plastic Moulded Commercial Terrariums ......................................................35 Mesh Terrariums ..............................................................................................................................................................................................35

OUTDOOR ENCLOSURES ........................................................................................................................................36

Pits ...........................................................................................................................................................................................................................................36 Aviaries ............................................................................................................................................................................................................................38 ENCLOSURE SIZE ..........................................................................................................................................................................................40 Minimum Enclosure Sizes .................................................................................................................................................................40 COMPATIBILITY ...............................................................................................................................................................................................41 page 3

VENTILATION ......................................................................................................................................................................................................42 SUBSTRATE .............................................................................................................................................................................................................43 Sand ......................................................................................................................................................................................................................................43 Soil ...........................................................................................................................................................................................................................................44 Gravel..................................................................................................................................................................................................................................44 Scoria...................................................................................................................................................................................................................................44 Leaf Litter .....................................................................................................................................................................................................................44 Potting Mix ................................................................................................................................................................................................................45 Sphagnum Moss ...............................................................................................................................................................................................45 Peat.........................................................................................................................................................................................................................................45 Bark and Wood Chip...................................................................................................................................................................................45 Wood Shavings ...................................................................................................................................................................................................45 Corn Cob Litter ....................................................................................................................................................................................................46 Walnut Shell Litter .........................................................................................................................................................................................46 Alfalfa/Lucerne Pellets ...........................................................................................................................................................................46 Compressed Timber Pellets ...........................................................................................................................................................46 Compressed Newspaper Pellets.............................................................................................................................................46 Zeolite and Clumping Cat Litter .............................................................................................................................................46 Paper....................................................................................................................................................................................................................................46 Artificial Grass ......................................................................................................................................................................................................46 Indoor/Outdoor Carpet ........................................................................................................................................................................47

HIDE SITES .....................................................................................................................................................................................................47

Vertical Hide Sites ..........................................................................................................................................................................................47 Horizontal Hide Sites ................................................................................................................................................................................48

ENCLOSURE ENRICHMENT ...............................................................................................................................50

Surface Litter ..........................................................................................................................................................................................................50 Branches and Hollows.............................................................................................................................................................................50 Artificial Plants ....................................................................................................................................................................................................51 Dried Plants ..............................................................................................................................................................................................................51 Live Plants ...................................................................................................................................................................................................................52

HEATING ..............................................................................................................................................................................................................53 HEAT CORD OR TAPE ..............................................................................................................................................................................53 HEAT MATS ..............................................................................................................................................................................................................54 HEAT ROCKS ..........................................................................................................................................................................................................54 CERAMIC HEATERS....................................................................................................................................................................................55 GLOBES...........................................................................................................................................................................................................................55 Standard Incandescent Globes................................................................................................................................................55 Reflector Globes ...............................................................................................................................................................................................55 Reptile Lamps .......................................................................................................................................................................................................55 Halogen Bulbs ......................................................................................................................................................................................................56 Infrared Globes ...................................................................................................................................................................................................56 Mercury Vapour Lamps (MVLs) ................................................................................................................................................56 Metal Halide Bulbs........................................................................................................................................................................................56 page 4

LIGHTING ..........................................................................................................................................................................................................58 THE SCIENCE OF LIGHTING .......................................................................................................................................................58 Visible Light..............................................................................................................................................................................................................58 Infrared ............................................................................................................................................................................................................................58 Ultraviolet A (UV-A) .....................................................................................................................................................................................58 Ultraviolet B (UV-B) ......................................................................................................................................................................................59 Ultraviolet C (UV-C)......................................................................................................................................................................................61 LIGHTING OPTIONS .................................................................................................................................................................................62 UV-B Emitting Fluorescent Tubes.........................................................................................................................................62 Black Lights...............................................................................................................................................................................................................63 Compact UV-B Emitting Lamps ...............................................................................................................................................63 Mercury Vapour Lamps .........................................................................................................................................................................64 ‘Modified’ Halogen (Quartz or Dichroic Halogens) Lamps.........................................................65 Metal Halide Lamps ....................................................................................................................................................................................65

THERMOSTATS ...................................................................................................................................................................................66

Probe Thermostats .......................................................................................................................................................................................66 On/Off Thermostats ....................................................................................................................................................................................66 Dimming Thermostats............................................................................................................................................................................66 Pulse Proportional Thermostats ............................................................................................................................................67

HUMIDITY .......................................................................................................................................................................................................67

FEEDING METHODS AND NUTRITION

INVERTEBRATE FOOD ITEMS......................................................................................................................70

Crickets—Acheta domestica .................................................................................................................................................................70 Cockroaches ............................................................................................................................................................................................................70 Mealworms—Tenebrio molitor .........................................................................................................................................................71 King Mealworms or Superworms—Zophobas morio .................................................................................71 Flies/Maggots/Pupae—Musca vetutissima ..................................................................................................................72 Slaters.................................................................................................................................................................................................................................72 Silkworms—Bombyx mori and other Caterpillars ...........................................................................................73 Termites ..........................................................................................................................................................................................................................73 Earthworms—Lumbricus terrestrius ...........................................................................................................................................73 Locusts—Chortoicetes terminifera .................................................................................................................................................73 Fruit Flies—Drosophila species .....................................................................................................................................................74 Snails—Helix aspersa and other species .........................................................................................................................74 Crustacea—Freshwater Crayfish, Prawns and Shrimp......................................................................74 Wax worms—Galleria mellonella ...................................................................................................................................................75 Wild Fodder ..............................................................................................................................................................................................................75 Nutritional Data Averages for Invertebrate Diets.....................................................................................76

VERTEBRATE FOOD ITEMS ................................................................................................................................77

Rats and Mice ........................................................................................................................................................................................................77 Chicks and Small Birds ...........................................................................................................................................................................78 Guinea Pigs ...............................................................................................................................................................................................................78 Fish ..........................................................................................................................................................................................................................................78 Reptiles ............................................................................................................................................................................................................................79 page 5

Nutritional Data Averages for Vertebrate Diets ...........................................................................................79

ARTIFICIAL DIETS.......................................................................................................................................................................80 HERBIVOROUS/OMNIVOROUS DIETS ....................................................................................................................80 Calcium to Phosphorus Ratio in Fruits and Vegetables ..................................................................81 CARNIVOROUS/INSECTIVOROUS DIETS ...........................................................................................................83

CULTURING INSECT FOOD ITEMS ..................................................................................................84

DIETARY SUPPLEMENTS .........................................................................................................................................93 CALCIUM ......................................................................................................................................................................................................................93 Gut Loading .............................................................................................................................................................................................................93 Dusting.............................................................................................................................................................................................................................94 PROTEIN........................................................................................................................................................................................................................95

FEEDING FACILITIES ...........................................................................................................................................................95 FEEDING PROBLEMS .........................................................................................................................................................96 TREATMENT ...........................................................................................................................................................................................................98 Assist Feeding.......................................................................................................................................................................................................98 Force Feeding........................................................................................................................................................................................................99 Tube Feeding .........................................................................................................................................................................................................99

BREEDING VISUAL SEXING.............................................................................................................................................................................100

Colour.............................................................................................................................................................................................................................100 Size ......................................................................................................................................................................................................................................100 Femoral and Preanal Pores .........................................................................................................................................................101 Hemipenal Bulges......................................................................................................................................................................................101 Paracloacal Spur Structures ......................................................................................................................................................101 OTHER SEXING TECHNIQUES .............................................................................................................................................101 Hemipenal Probing .................................................................................................................................................................................101 Hemipenal Popping................................................................................................................................................................................102 Hemipenal Transillumination .................................................................................................................................................103 Hemipenal Observation ..................................................................................................................................................................105 Hemipenal Plug Observation .................................................................................................................................................105 Hemipenal Palpation ............................................................................................................................................................................106 page 6

BREEDING AGE ..............................................................................................................................................................................106 COURTSHIP..............................................................................................................................................................................................106 MATING ..............................................................................................................................................................................................................106 STRATEGIES TO ENHANCE BREEDING SUCCESS................................107 COOLING..................................................................................................................................................................................................................107 SEPARATION .....................................................................................................................................................................................................109

REPRODUCTION ........................................................................................................................................................................109 REPRODUCTIVE STRATEGIES.............................................................................................................................................109 EGG TYPE ................................................................................................................................................................................................................110 CLUTCH & LITTER SIZE ...................................................................................................................................................................110 BREEDING FREQUENCY ...............................................................................................................................................................111 GRAVIDITY ...........................................................................................................................................................................................................111 CARING FOR BREEDING FEMALE SKINKS ...................................................................................................112

NEST FACILITIES ........................................................................................................................................................................113 ABOREAL SPECIES .................................................................................................................................................................................113 TERRESTRIAL SPECIES....................................................................................................................................................................114

EGG LAYING & BIRTHING...................................................................................................................................114 EGG MANAGEMENT ............................................................................................................................................................................115 Collecting and Handling .................................................................................................................................................................115 Determining Egg Viability ............................................................................................................................................................116

ARTIFICIAL INCUBATION ...................................................................................................................................118 INCUBATION FACILITY ...................................................................................................................................................................118 CONTAINERS.....................................................................................................................................................................................................119 HEATING ...................................................................................................................................................................................................................120 TEMPERATURE CONTROL .........................................................................................................................................................121 INCUBATION MEDIUM ....................................................................................................................................................................121 Vermiculite.............................................................................................................................................................................................................122 Perlite..............................................................................................................................................................................................................................122 Sphagnum Moss ...........................................................................................................................................................................................122 True Peat Moss ................................................................................................................................................................................................122 Coir Peat Moss ..................................................................................................................................................................................................122 Sand ..................................................................................................................................................................................................................................123 No Substrate .......................................................................................................................................................................................................123 INCUBATION REGIMES ...................................................................................................................................................................123 TEMPERATURE DEPENDENT SEX DETERMINATION.................................................................123

NATURAL INCUBATION ..........................................................................................................................................126 page 7

HATCHLING CARE ..................................................................................................................................................................126 FEEDING ...................................................................................................................................................................................................................126 Feeding Frequency ..................................................................................................................................................................................127 Supplementation ........................................................................................................................................................................................127 LIGHTING ................................................................................................................................................................................................................127 HOUSING.................................................................................................................................................................................................................127 HEATING ...................................................................................................................................................................................................................127 COMPATIBILITY ...........................................................................................................................................................................................127

COMMON DISEASES AND DISORDERS

DISCLAIMER............................................................................................................................................................................................128 NUTRITIONAL DISORDERS ...............................................................................................................................128 OBESITY ....................................................................................................................................................................................................................128 METABOLIC BONE DISEASE (CALCIUM/VITAMIN D3 DEFICIENCY) ...............129 Early Onset Metabolic Bone Disease ..........................................................................................................................129 Late Onset Metabolic Bone Disease ............................................................................................................................130 Delayed Metabolic Bone Disease.....................................................................................................................................130 Reproductive Metabolic Bone Disease...................................................................................................................131 GUT IMPACTION ........................................................................................................................................................................................131

PARASITIC DISORDERS ..............................................................................................................................................133 INTERNAL PARASITES .....................................................................................................................................................................133 EXTERNAL PARASITES....................................................................................................................................................................134

SKIN DISORDERS ........................................................................................................................................................................135 DYSECDYSIS.......................................................................................................................................................................................................135 SCALE ROT ............................................................................................................................................................................................................136

NAIL, TOE AND LIMB DISORDERS...................................................................................................138 EYE DISORDERS.............................................................................................................................................................................139 EYE TRAUMA.....................................................................................................................................................................................................139 PHOTOKERATOCONJUNCTIVITIS ...............................................................................................................................139 PRIMARY BACTERIAL EYE INFECTIONS ..........................................................................................................139

RESPIRATORY DISORDERS................................................................................................................................139 BACTERIAL PNEUMONIA ...........................................................................................................................................................139 VITAMIN A DEFICIENCY ...............................................................................................................................................................140 HUMIDITY RELATED PROBLEMS..................................................................................................................................140 PARASITIC PNEUMONIA .............................................................................................................................................................140

TRAUMA............................................................................................................................................................................................................140 BITE INJURIES .................................................................................................................................................................................................140 THERMAL BURNS .....................................................................................................................................................................................141 page 8

REPRODUCTIVE DISORDERS.......................................................................................................................142 PRE-OVULATORY AND POST-OVULATORY STASIS (EGG BINDING OR DYSTOCIA) ..........................................................................................................................................142 UTERINE INFECTION ..........................................................................................................................................................................144 HEMIPENAL INJURIES AND INFECTION..........................................................................................................145 CONGENITAL DEFECTS ..................................................................................................................................................................145

NASAL AND ORAL DISORDERS.........................................................................................................147

NASAL ABRASIONS—NOSE RUBS ............................................................................................................................147 JAW DISEASE/PERIODONTITIS/STOMATITIS.........................................................................................147

ADMINISTRATION OF MEDICATIONS ...................................................................................148 Subcutaneous or Intramuscular Injections .....................................................................................................148 Liquid Oral Medication......................................................................................................................................................................149 Oral Tablet Medication.......................................................................................................................................................................151

MAKING THE MOST OF YOUR REPTILE VETERINARIAN ..........................................................................................................................................151

SPECIES

BLUE-TONGUED AND SHINGLEBACK SKINKS

PRONUNCIATION .....................................................................................................................................................................................154

DESCRIPTION..............................................................................................................................................................................158

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................158

IN THE WILD .....................................................................................................................................................................................169

DISTRIBUTION AND HABITAT ...........................................................................................................................................169

IN CAPTIVITY ...............................................................................................................................................................................171

STATUS ........................................................................................................................................................................................................................171

HOUSING .......................................................................................................................................................................................................171 INDOOR ENCLOSURES....................................................................................................................................................................171 Summary...................................................................................................................................................................................................................173 OUTDOOR ENCLOSURES ............................................................................................................................................................173 COMPATIBILITY ...........................................................................................................................................................................................174

BREEDING RECORDS FOR BLUE-TONGUED SKINK SPECIES ......................................178 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................179 LONGEVITY .........................................................................................................................................................................................................182

ACKNOWLEDGEMENTS .........................................................................................................................................182 page 9

BURROWING SKINKS PRONUNCIATION .....................................................................................................................................................................................183

DESCRIPTION..............................................................................................................................................................................187

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................187

IN THE WILD .....................................................................................................................................................................................191

DISTRIBUTION AND HABITAT ...........................................................................................................................................191

IN CAPTIVITY ...............................................................................................................................................................................194

HOUSING .......................................................................................................................................................................................................194 INDOOR ENCLOSURES....................................................................................................................................................................194 Summary...................................................................................................................................................................................................................195 OUTDOOR ENCLOSURES ............................................................................................................................................................196 COMPATIBILITY ...........................................................................................................................................................................................196

FEEDING ..........................................................................................................................................................................................................196 BREEDING....................................................................................................................................................................................................197 INCUBATION AND HATCHLING DEVELOPMENT..............................................................................198 BREEDING RECORDS FOR BURROWING SKINK SPECIES..................................................199 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................200 LONGEVITY .........................................................................................................................................................................................................200

ACKNOWLEDGEMENTS .........................................................................................................................................200

CREVICE SKINKS AND THEIR ALLIES PRONUNCIATION .....................................................................................................................................................................................201

DESCRIPTION..............................................................................................................................................................................202

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................202

IN THE WILD .....................................................................................................................................................................................213

DISTRIBUTION AND HABITAT ...........................................................................................................................................213

IN CAPTIVITY ...............................................................................................................................................................................214

HOUSING .......................................................................................................................................................................................................215 INDOOR ENCLOSURES....................................................................................................................................................................215 Summary...................................................................................................................................................................................................................218 OUTDOOR ENCLOSURES ............................................................................................................................................................219 COMPATIBILITY ...........................................................................................................................................................................................220

BREEDING....................................................................................................................................................................................................221 BREEDING RECORDS FOR CREVICE SKINKS AND THEIR ALLIED SPECIES ...................................................................................................................................................................224 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................225 LONGEVITY .........................................................................................................................................................................................................226

ACKNOWLEDGEMENTS .........................................................................................................................................226

FOREST AND WATER SKINKS PRONUNCIATION .....................................................................................................................................................................................227

DESCRIPTION..............................................................................................................................................................................232

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................232

IN THE WILD .....................................................................................................................................................................................235

DISTRIBUTION AND HABITAT ...........................................................................................................................................235

IN CAPTIVITY ...............................................................................................................................................................................236

HOUSING .......................................................................................................................................................................................................236 INDOOR ENCLOSURES....................................................................................................................................................................236 Summary...................................................................................................................................................................................................................237 OUTDOOR ENCLOSURES ............................................................................................................................................................238 COMPATIBILITY ...........................................................................................................................................................................................238

FEEDING ..........................................................................................................................................................................................................238 BREEDING....................................................................................................................................................................................................239 BREEDING RECORDS FOR FOREST AND WATER SKINK SPECIES .......................241 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................242 LONGEVITY .........................................................................................................................................................................................................242

ACKNOWLEDGEMENTS .........................................................................................................................................242

PRICKLY FOREST SKINK PRONUNCIATION .....................................................................................................................................................................................243

DESCRIPTION..............................................................................................................................................................................244

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................244

IN THE WILD .....................................................................................................................................................................................246

DISTRIBUTION AND HABITAT ...........................................................................................................................................246

IN CAPTIVITY ...............................................................................................................................................................................247

INDOOR ENCLOSURES....................................................................................................................................................................247 Summary...................................................................................................................................................................................................................249 OUTDOOR ENCLOSURES ............................................................................................................................................................249 COMPATIBILITY ...........................................................................................................................................................................................249

BREEDING RECORDS FOR THE PRICKLY FOREST SKINK ...................................................250 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................251 LONGEVITY .........................................................................................................................................................................................................251

ACKNOWLEDGEMENTS .........................................................................................................................................251

RAINBOW SKINKS PRONUNCIATION .....................................................................................................................................................................................252

DESCRIPTION..............................................................................................................................................................................259

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................259

IN THE WILD .....................................................................................................................................................................................264

DISTRIBUTION AND HABITAT ...........................................................................................................................................264

IN CAPTIVITY ...............................................................................................................................................................................268

HOUSING .......................................................................................................................................................................................................270 INDOOR ENCLOSURES....................................................................................................................................................................270 Summary...................................................................................................................................................................................................................271 OUTDOOR ENCLOSURES .......................................................................................................................................................... 271 COMPATIBILITY ...........................................................................................................................................................................................272

INCUBATION AND HATCHLING DEVELOPMENT..............................................................................274 BREEDING RECORDS FOR RAINBOW SKINK SPECIES ............................................................274 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................274 LONGEVITY .........................................................................................................................................................................................................274

ACKNOWLEDGEMENTS .........................................................................................................................................274

SAND SWIMMERS PRONUNCIATION .....................................................................................................................................................................................275

DESCRIPTION..............................................................................................................................................................................279

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................279 page 12

IN THE WILD .....................................................................................................................................................................................283

DISTRIBUTION AND HABITAT ...........................................................................................................................................283

IN CAPTIVITY ...............................................................................................................................................................................285

INDOOR ENCLOSURES....................................................................................................................................................................286 Summary...................................................................................................................................................................................................................287 OUTDOOR ENCLOSURES ............................................................................................................................................................287 COMPATIBILITY ...........................................................................................................................................................................................288

INCUBATION AND HATCHLING DEVELOPMENT..............................................................................290 BREEDING RECORDS FOR SAND SWIMMER SPECIES.............................................................291 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................291 LONGEVITY .........................................................................................................................................................................................................291

ACKNOWLEDGEMENTS .........................................................................................................................................291

SLENDER BLUE-TONGUED AND PINK-TONGUED SKINKS PRONUNCIATION .....................................................................................................................................................................................292

DESCRIPTION..............................................................................................................................................................................296

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................296

IN THE WILD .....................................................................................................................................................................................301

DISTRIBUTION AND HABITAT ...........................................................................................................................................301

IN CAPTIVITY ...............................................................................................................................................................................302

HOUSING .......................................................................................................................................................................................................302 INDOOR ENCLOSURES....................................................................................................................................................................302 Summary...................................................................................................................................................................................................................304 OUTDOOR ENCLOSURES ............................................................................................................................................................304 COMPATIBILITY ...........................................................................................................................................................................................305

BREEDING RECORDS FOR CYCLODOMORPHUS SKINK SPECIES .........................308 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................308 LONGEVITY .........................................................................................................................................................................................................309

ACKNOWLEDGEMENTS .........................................................................................................................................309 page 13

SMALL TERRESTRIAL SKINKS PRONUNCIATION .....................................................................................................................................................................................310

DESCRIPTION..............................................................................................................................................................................316

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................316

IN THE WILD .....................................................................................................................................................................................320

DISTRIBUTION AND HABITAT ...........................................................................................................................................320

IN CAPTIVITY ...............................................................................................................................................................................323

HOUSING .......................................................................................................................................................................................................323 INDOOR ENCLOSURES....................................................................................................................................................................323 Summary...................................................................................................................................................................................................................325 OUTDOOR ENCLOSURES .......................................................................................................................................................... 325 COMPATIBILITY ...........................................................................................................................................................................................325

FEEDING ..........................................................................................................................................................................................................325 BREEDING....................................................................................................................................................................................................326 INCUBATION AND HATCHLING DEVELOPMENT..............................................................................328 BREEDING RECORDS FOR SMALL TERRESTRIAL SKINK SPECIES .....................329 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................330 LONGEVITY .........................................................................................................................................................................................................330

ACKNOWLEDGEMENTS .........................................................................................................................................330

STRIPED SKINKS PRONUNCIATION .....................................................................................................................................................................................331

DESCRIPTION..............................................................................................................................................................................335

ADULTS, JUVENILES, SEXING, SUBSPECIES ............................................................................................335

IN THE WILD .....................................................................................................................................................................................338

DISTRIBUTION AND HABITAT ...........................................................................................................................................338

IN CAPTIVITY ...............................................................................................................................................................................340

HOUSING .......................................................................................................................................................................................................340 INDOOR ENCLOSURES....................................................................................................................................................................340 Summary...................................................................................................................................................................................................................341 OUTDOOR ENCLOSURES ............................................................................................................................................................342 COMPATIBILITY ...........................................................................................................................................................................................342

BREEDING....................................................................................................................................................................................................343 INCUBATION AND HATCHLING DEVELOPMENT..............................................................................344 BREEDING RECORDS FOR STRIPED SKINK SPECIES .................................................................344 HYBRIDISATION AND COLOUR VARIANTS .................................................................................................344 LONGEVITY .........................................................................................................................................................................................................345

ACKNOWLEDGEMENTS .........................................................................................................................................345

AUSTRALIAN HERPETOLOGICAL SOCIETIES AND USEFUL WEBSITES HERPETOLOGICAL SOCIETIES ..........................................................................................................................................346 OTHER USEFUL WEBSITES.......................................................................................................................................................347

BIBLIOGRAPHY

PRINTED LITERATURE......................................................................................................................................................................347 ONLINE RESOURCES ..........................................................................................................................................................................350

S EIPPER

GLOSSARY .....................................................................................................................................................................................352

Carlia pectoralis

page 15

HANDLING AND HYGIENE

D BROWN

• The skin should shed cleanly. Retained sheds may not be significant in a single individual but if multiple specimens within the enclosure have problems, it may indicate overly hot and dry conditions. • Inspect the tail—is it the original or a modified tail? A modified tail is usually defined by a significant change in the tail colouration and surface features. A modified tail is not a significant issue but some keepers require a perfect tail on a specimen. A modified tail may indicate fighting between individuals, rough handling, wild origins or heat or cold stress. An individual with tail changes is no less healthy than one with a normal tail—but it may demand a lower price. • Check for surface parasites. Inspect the eye sockets and armpits for red mites. Although these parasites are non pathogenic, they can be unsightly. They often occur in specimens housed in outdoor enclosures, in enclosures with natural furnishings, such as leaf litter, and in wild caught specimens. • Determine if the individual has been sexed. Ask the seller about the sexing method that has been used and, if possible, request the sexual features be demonstrated to you. • Inspect the skink’s enclosure. Note if the conditions are clean and tidy or if the occupants are overcrowded. • Observe the health of other skinks in the collection. Note if the seller appears to possess a genuine knowledge of the specimens in his or her care.

The use of correct handling techniques when managing lizards is necessary to prevent injury to the lizard and to yourself, the handler. Most specimens employ anti-predator mechanisms such as tail dropping—known as tail autotomy. They are more at risk of injury when employing these methods than you. Large specimens may deter handlers by inflicting pain upon the aggressor through biting or scratching. Correct handling techniques will avoid small lizards employing anti-predator mechanisms and reduce the risk of injury inflicted by large specimens. Following Cyclodomorphus gerrardii. Most skinks have the ability are the specific handling issues associated to drop their tails at predetermined separation points with skinks and techniques that may be enacted to avoid problems. Skinks posses very few active defence mechanisms other than biting, urination or defecation. The latter is almost a certainty with some species—particularly Eremiascincus—whereas larger species will more commonly urinate when handled. Bites by most small skinks are of little concern—that is, if they manage to bite at all—however, the pressure exerted by medium and large specimens can be quite surprising. Skinks are tenacious biters. Although their teeth are rarely sharp enough to cut the skin, they can crush snail shells with their bite. If you do become the victim of a bite, attempts to remove a skink can merely aggravate the situation and result in a firmer bite. In most cases, your grip on the skink should be released, page 22

D BROWN

Commercial ‘clamp lamp’ from IKEA™

Using a mounting block to attach a lamp to a glass surface

IKEA™ sells a wonderful range of ‘clamp lamps’. Position heat lamps towards one end of the enclosure to allow a heat gradient to be established and to encourage air flow from one area to another. Use in-line dimming units such as the IKEA Dimma™ in small enclosures to regulate maximum temperatures and avoid overheating.

LIGHTING THE SCIENCE OF LIGHTING The provision of appropriate lighting is important for the general wellbeing of many reptile species. There is much debate regarding the species that do and do not require lighting and what types of lighting are suitable. Lighting can be broken down into visible light that allows us to see our reptiles and reptiles to see each other, infrared that produces heat, Ultraviolet A (UV-A), Ultraviolet B (UV-B) and Ultraviolet C (UV-C).

Visible Light Any type of incandescent bulb or fluorescent tube will supply visible light.

Infrared This is utilised predominantly for its heating properties.

Ultraviolet A (UV-A) This essential form of light occurs in sunlight at wavelengths of 320–400 nanometres (nm) providing beneficial behavioural and psychological effects. Although these effects are difficult to measure, it is well known that direct sunlight causes lizards to behave differently than when exposed to artificial light—for example, moving a blue-tongued skink into an outside enclosure can cause its colouration to change and its personality and behaviour to alter. UV-A has no impact on vitamin activation but is a part of a reptile’s visible spectrum. Within it, they can see colours and patterns that are not visible to humans but which are important in interactions between individual reptiles. Lizards also recognise UV-A reflective markings on plant and insect food items. UV-A is often supplied with UV-B or via full spectrum lighting. Determining the required level of UV-A is impossible due to the varying needs of each species. page 58

light doubles. The use of a curved reflector doubles the UV-B output by focusing any lost light downwards. Double fluorescent tubes will double the output, however, this is equal to the same as one tube with a reflector. Double tubes with reflectors triple the output. Mesh covers significantly reduce UV-B output. A disadvantage of all UV-B emitting devices is a process known as decay. As soon as a new tube is switched on and achieves a stable temperature, reactions occur between the phosphorous coating, mercury, tungsten and electrical components. These reactions result in a gradual reduction in the lamp’s UV-B output—initially approximately 5–10% in the first 100 hours of use, then a slower decline over the rest of its working life. The UV-B output never ceases but it may reach a point where the intensity is ineffective for vitamin D3 metabolism. Tubes should be replaced every 6–12 months or as indicated by a UV meter.

Black Lights Often used in nightclubs as a decorative effect to enhance white colouration, black lights are specific UV-producing fluorescent tubes. The Black Light Blue™ lamp (BLB) is not recommended— it produces dangerously high levels of UV light. The NEC T10™ black light is widely used in herpetological circles and produces ideal levels of UV-A and UV-B at distances of 20–40cm. These lights decay rather fast and should be replaced every six months. They should be paired with a standard fluorescent or full spectrum tube, as they produce inadequate visible light.

Compact UV-B Emitting Lamps D BROWN

These narrow fluorescent tubes have been modified to fit into a small area by twisting and compressing the tube and mounting it on a normal light fitting, usually an Edison screw. They require no further modification as the ballast starter is mounted in the base. UV-B compact lamps provide a diffuse but intense UV-B glow directed downwards, low heat and a uniform light gradient in a vertical fashion.

Compact UV-B and reflector

D BROWN

NEC-T10™ black light and UV-B tubes

Compact UV-B lamps

page 63

BREEDING VISUAL SEXING The correct identification of gender is the first step towards breeding success. For many species, this process is simple—for others it requires educated guesswork. There are various methods of sexing skinks, which range in complexity and reliability. Visual sexing is one of the most common methods and involves the examination of a skink’s secondary sexual characteristics including colour, size and hemipenal bulges. Following is an outline of each method. For more specific details of distinguishing features in each species refer to the individual species chapters.

Colour

D BROWN

Many skink species display considerable sexual dimorphism with regard to colour patterns in particular. Some species display distinct differences in overall colouration—for example, males may display colouration and females lack colouration. In other species, males and females may be similar in colouration and males may display highlights in areas such as the chest, face, throat and ventral abdomen.

Liopholis modesta male (below). Some skinks may show subtle visible sexual dimorphism in colouration

Carlia jarnoldae male (below). Some skinks show striking seasonal sexual dimorphism

Size There is considerable disparity in size between the sexes of many species of skinks, with males often 50% larger than the size of females. In many burrowing skinks, including Anomalopus and Lerista, and in Cyclodomorphus skinks, females are invariably the larger gender. During hatchling stage, there is generally no significant difference in the total length of the sexes, however hatchlings of the dominant sex may sometimes be bulkier with a broader head, a broader neck and wider shoulders. The female appears smaller and more delicate. There are many other methods by which sex can be determined by size, depending on the species kept. Variations in the structural components of the body may be apparent when comparing two individuals with the same SVL. These variations usually appear as differences in the shape and size of the head and the overall build of the body. The male is generally larger with a wider and thicker head, a broader neck and wider shoulders. The female appears smaller and more delicate. page 100

The nesting substrate should be kept wet enough that it retains moisture for 5–7 days—so that you are not required to interfere with the nest site regularly. It should be loosely packed to ensure the egg laying female can easily push or dig her way into the substrate—it should not be so loose that it offers no burrowing support. For arboreal species there is a preference for entrance holes placed on the top of the nesting container. The containers should be almost completely filled to the top, allowing just enough space for the female to rest comfortably on top of the substrate. Regardless of the container depth, most females will lay their eggs directly on the bottom of the container. An ideal minimum container size is 1.5–2 x SVL deep x 1–2 SVL wide. This allows ample room to dig, turn around and position for egg laying.

TERRESTRIAL SPECIES

J LUKE

Terrestrial skink species tend to be fussier about their nesting sites, possibly because they would normally have more choice regarding the features of an egg laying site in the wild, such as soil texture, soil moisture, soil depth and orientation of the nest site. In captivity, suitable nesting sites are either a nest container that bears little resemblance to a natural nest site or a substrate of uniform consistency and limited depth. Thankfully, many terrestrial species are somewhat understanding of variation in nesting conditions if the nest sites are prepared appropriately and alternative sites are eliminated. Generally, the acceptance of available conditions depends as much on the species as the individual specimen. Multi-generational captive bred individuals readily accept artificial nest sites and will just dig a hole, lay their eggs and get on with life. Other female specimens may make several attempts at digging before selecting a site to their liking. Nesting containers for terrestrial species should measure approximately 2−3 SVL long x 2 SVL wide x 0.5−1 SVL high. The entrance hole may be positioned on the side or top of the container. Artificial nesting sites may be more readily accepted if basking sites located adjacent to the tub lip are raised to the same level using something such as a large paver or brick.

EGG LAYING AND BIRTHING Female skinks commence egg laying after digging a hole in the nesting substrate, generally close to the bottom of the enclosure or container. She will then turn around, reverse into the hole, lay her eggs and then backfill the hole with soil. In burrowing skinks, the female will use her head to force her body deep into the nesting substrate, occasionally flexing sideways to widen the hole. If large chunks of material impede the passage of her head, she may grip the items with her mouth and pull them out of the way. A small cavity will usually be present around the immediate vicinity of the eggs while the remainder of the tunnel is well packed with soil. The female will reverse out of the hole after laying, and push the soil back in place with her head. Some species lay communally with dozens of eggs found in a single area. Whether this is due to a lack of suitable laying sites or a ‘safety in numbers’ strategy is not clear. Eremiascincus richardsonii. Most skink species dig an enlarged cavity at the end of the burrow in which to place the eggs

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W COSSELL

D BROWN

A commercial Hovabator™ poultry incubator being used for reptile eggs

A commercial Kimani Reptihatch™, a quality reptile specific incubator

overheated. Simple 12V computer fans are ideal for this purpose and may be set up using a 12V transformer—your electrician should be able to inexpensively wire it up for you. Avoid installing a 240V computer fan—these generate a fair amount of heat and may make it difficult to control the temperature within the incubator.

TEMPERATURE CONTROL An incubator will require a thermostat to maintain the appropriate temperature for hatching. When using incandescent bulbs, a simple probe thermostat, on/off type thermostat or dimming thermostat is sufficient. The sensor for the thermostat should be positioned away from the heat source to ensure it measures the actual air temperature. I have found it useful to place the sensor inside a dummy container, such as an incubation container filled with dry medium to achieve this. Use of a dimming thermostat will lengthen the life of the light bulb in comparison to other types of thermostats. When using heat cord, a probe, on/off thermostat or dimming thermostat can be used, however a pulse proportional thermostat provides more precise control over temperatures in a smaller range as modifications to heat cord power supply are made more often than with other thermostats. Pulse proportional thermostats generally use less power, as they rarely force the heat cord to work at full power. Temperatures should be similar throughout an incubator. Multiple digital thermometer probes may help achieve this, as they allow temperatures to be monitored at various sites. If significant differences are noted, they can be corrected by changing the direction of fans to move heat around. Alternatively, different incubation regimes may be utilised in different areas, taking advantage of higher temperatures on upper shelves.

INCUBATION MEDIUM Incubation medium is the material or substrate into which lizard eggs may be placed for hatching. It should be biochemically stable, well aerated, sterile, and retain moisture without decomposition. Suitable incubation mediums include vermiculite, perlite, sphagnum moss, true peat moss, coir peat moss, sand and no substrate. page 121

D BROWN

COMMON DISEASES AND DISORDERS DISCLAIMER

Although lizards are generally quite hardy by nature, they will occasionally become unwell or develop lesions—despite a keeper’s best intentions. This chapter will explore the common disorders that affect lizards, the associated clinical signs and treatment options. Most health issues require a degree of veterinary assistance, as many medications are available by prescription only. Therefore, a full physical examination of your lizard by a veterinarian is often required before medication can be prescribed. This is a legal requirement designed to establish proper drug use and slow the development of drug resistance caused by the inappropriate use of medication. Veterinarians who fail to meet these legal requirements may be fined and lose their practicing licence. Please do not ask your veterinarian to supply drugs without a prescription. The numerous medications discussed in this chapter are not for your own home treatment—my aim is to assist Basic anatomy of a skink Lampropholis delicata you if you ever seek advice from a nonreptile veterinarian who is unsure of the available treatment options. Many of the medications recommended here are rarely marketed for use with reptiles—they are often not registered as reptile medications and their recommended dosages have been developed using anecdotal evidence—not through official clinical trials conducted by drug companies. The medications recommended in this chapter are believed to be safe based on current evidence in veterinary literature. The following advice is not intended to be a substitute to veterinary care. Always follow the instructions provided by your veterinarian. Any recommendation in this text is to be used at your own risk.

NUTRITIONAL DISORDERS OBESITY Like in any species of animal, lack of activity coupled with excess nutrition can lead to obesity in lizards. In most cases, obese lizards are quite obviously quite rotund, usually around the abdomen and tail base. Other specimens may store fat internally in large abdominal fat pads that may not seem obvious from the outside or may mimic gravidity. The major organ influenced by obesity is page 128

D BROWN

Tiliqua scincoides intermedia—male (below) and female. In two skinks with identical trunk lengths, males usually have proportionately longer necks and heads

SEXING

D BROWN

Blue-tongued and shingleback skinks are not easily sexed until they reach at least 80% of adult SVL. Most herpetologists rely on visual sexing to distinguish males and females, however there are many urban myths surrounding distinguishing features—including that males have thinner and more lateral bodies and thicker throats than females, orange eyes compared to the female’s brown eyes and brighter ventral skin colour. Although these supposed distinguishing features

Head of a typical male Tiliqua scincoides intermedia

Head of a typical female Tiliqua scincoides intermedia

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D BROWN M THOW

S EIPPER

Albino Tiliqua scincoides scincoides

S EIPPER

Albino Tiliqua scincoides scincoides

A ELLIOTT

Albino Tiliqua scincoides scincoides

Calico (Piebald) Tiliqua nigrolutea

Albino Tiliqua nigrolutea

M THOW

T. r. rugosa forms natural intergrade zones where they meet T. r. aspera and T. r. pallara . A natural hybrid zone between T. r. aspera and T. r. rugosa occurs in the area between the Zanthus and Balladonia regions in Western Australia. A natural hybrid zone between T. r. rugosa and T. r. pallara occurs near the Murchison River and in the surrounding hinterland in Western Australia. Colour variants are common in this group. Patternless Tiliqua nigrolutea Populations in higher altitude areas are generally darker, presumably to aid in thermoregulation. The Shingleback Skink T. rugosa varies dramatically in some populations. page 180

G STEPHENSON S MACDONALD

Some rainbow skinks possess obvious striking colours, such as Carlia schmeltzii

DESCRIPTION ADULTS

Rainbow skinks are small, generally colourful skinks. They range in size— the smallest species Lygisaurus aeratus measures 30mm SVL and the largest species Carlia rostralis measures 70mm SVL. The majority of species in this group measure 38–60mm SVL. A typical specimen measuring an average length of 45mm SVL will weigh an average of 2–3 grams. Other species have a more subtle beauty, such as Lygisaurus foliorum Colouration varies—most species in this group are referred to as rainbow skinks, although not all species are as brightly coloured as the name suggests. Most are plain brown with pale spotting and darker mottling. Some plain brown specimens may show considerable iridescence on their scales. Some species may be brown to greyish brown with bright red, blue or orange throats, necks, flanks and tails. Many species are similar in appearance and can be distinguished according to features such as the number of keels on their body scales and the shape of their ear opening. Some rainbow skinks display a peculiar and attractive habit of tail wriggling when they feel stressed, during feeding and when approaching each other. Different species move their tails in different manners, with some holding them at different angles from the ground, varying the speed and intensity at which the tail is waved. For example, C. amax waves its tail slowly at 40−70 degrees above the horizontal whereas the Shaded-litter Rainbow Skink C. munda waves its tail faster at 10−30 degrees above the horizontal. Other behaviours commonly used to assert and reinforce territories include head bobbing, conspicuous perching and the patrolling of territorial borders. page 259

COMPATIBILITY Sand swimmers are generally placid towards each other once compatible pairs or groups have been established. They can be housed in pairs. In large enclosures they can be housed in groups consisting of one male and 2−3 females. Males do not usually tolerate other males, but groups of females get along. Although usually peaceful, males have been known to occasionally turn on females with no warning. This may result in subtle injuries, such as a few missing scales, or it can be as significant as a lost tail or limb. At worst, injuries may become life threatening. I suspect this aggression may be caused by a lack of receptiveness from the female and a lack of places to escape to in these situations. Temporary separation for a couple of weeks will often restore harmony, provided it is the aggressor that is removed. Sand swimmers should never be kept with other skinks, as they will fight viciously. They may be housed with Central Netted Dragons Ctenophorus nuchalis with few problems—this combination has never caused me any issues. The Mosaic Desert Skink E. musivus has been recorded as eating other skinks.

FEEDING

D FISCHER

In the wild, sand swimmers feed on any available insect including grasshoppers, bugs, beetles, ants, termites, spiders, moths, flies and centipedes. Large specimens have been recorded consuming other reptiles such as small skinks, geckos and typhlopids and even very small mammals—presumably juveniles. In captivity, they will accept any insect item offered including cockroaches, crickets, slaters, termites and house flies. Some will also accept juvenile bearded dragon pellets and very small pinkie mice.

Eremiascincus richardsonii. Sand swimmers will tackle large food items with aggression

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