Sneak preview of A Guide to Australian Skinks in Captivity

A Guide to…

Australian SK

INK

S in Captivity By Dr D

anny Brown

BVSc (Hons) BSc (H

ons)

reptilepublications

By Dr Danny Brown BVSc (Hons) BSc (Hons)

A Guide to…Australian

SKINKSin Captivity

reptilepublications

SNEAK PREVIEW

ABOUT THE AUTHOR ....................................................................................................................................16

ACKNOWLEDGMENTS ......................................................................................................................................................17

INTRODUCTION ...............................................................................................................................................................19

GENERAL MANAGEMENT .............................................................................................................20

PET SUITABILITY ...........................................................................................................................................................................................20

CHOOSING YOUR STOCK ...............................................................................................................................................................20Selecting an Individual Lizard ...................................................................................................................................................21

HANDLING AND HYGIENE ...........................................................................................................................................................22

TRANSPORTATION ....................................................................................................................................................................................24Short Journeys.....................................................................................................................................................................................................24Long Journeys ......................................................................................................................................................................................................25Timber Boxes ..........................................................................................................................................................................................................26Plastic Containers ...........................................................................................................................................................................................27

PURCHASE AND FREIGHT ETIQUETTE ..................................................................................................................27Buyers ................................................................................................................................................................................................................................27Sellers .................................................................................................................................................................................................................................28

LEGAL REQUIREMENTS ....................................................................................................................................................................29

GENERAL SAFETY ........................................................................................................................................................................................30 SECURITY ....................................................................................................................................................................................................................31 QUARANTINE ......................................................................................................................................................................................................32

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

OUTDOOR ENCLOSURES ........................................................................................................................................36Pits ...........................................................................................................................................................................................................................................36Aviaries ............................................................................................................................................................................................................................38

ENCLOSURE SIZE ..........................................................................................................................................................................................40Minimum Enclosure Sizes .................................................................................................................................................................40 COMPATIBILITY ...............................................................................................................................................................................................41

CONTENTS

VENTILATION ......................................................................................................................................................................................................42 SUBSTRATE .............................................................................................................................................................................................................43Sand ......................................................................................................................................................................................................................................43Soil ...........................................................................................................................................................................................................................................44Gravel ..................................................................................................................................................................................................................................44Scoria ...................................................................................................................................................................................................................................44Leaf Litter .....................................................................................................................................................................................................................44 Potting Mix ................................................................................................................................................................................................................45 Sphagnum Moss ...............................................................................................................................................................................................45 Peat.........................................................................................................................................................................................................................................45Bark 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 ...............................................................................................................................50Surface 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 ................................................................................................................................................55Reflector Globes ...............................................................................................................................................................................................55 Reptile Lamps .......................................................................................................................................................................................................55 Halogen Bulbs ......................................................................................................................................................................................................56 Infrared Globes ...................................................................................................................................................................................................56Mercury Vapour Lamps (MVLs) ................................................................................................................................................56 Metal Halide Bulbs ........................................................................................................................................................................................56

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

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

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

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

VERTEBRATE FOOD ITEMS ................................................................................................................................77Rats and Mice ........................................................................................................................................................................................................77 Chicks and Small Birds ...........................................................................................................................................................................78 Guinea Pigs ...............................................................................................................................................................................................................78 Fish ..........................................................................................................................................................................................................................................78 Reptiles ............................................................................................................................................................................................................................79

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

ARTIFICIAL DIETS .......................................................................................................................................................................80

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

CULTURING INSECT FOOD ITEMS ..................................................................................................84Crickets—Acheta domestica .................................................................................................................................................................84Speckled Feeder Roaches—Nauphoeta cinerea ..................................................................................................87Locusts—Chortoicetes terminifera .................................................................................................................................................87Bush Flies—Musca vetutissima .........................................................................................................................................................88Mealworms—Tenebrio molitor and King Mealworms—Zophobas morio ........................90Slaters .................................................................................................................................................................................................................................91Lesser Wax worms (Indian Meal Moths)—Plodia interpunctella .................................................91Fruit Fly/Vinegar Fly/Ferment Fly—Drosophila species .....................................................................92

DIETARY SUPPLEMENTS .........................................................................................................................................93

CALCIUM ......................................................................................................................................................................................................................93Gut Loading .............................................................................................................................................................................................................93Dusting.............................................................................................................................................................................................................................94

PROTEIN........................................................................................................................................................................................................................95

FEEDING FACILITIES ...........................................................................................................................................................95

FEEDING PROBLEMS .........................................................................................................................................................96

TREATMENT ...........................................................................................................................................................................................................98Assist Feeding .......................................................................................................................................................................................................98 Force Feeding ........................................................................................................................................................................................................99Tube Feeding .........................................................................................................................................................................................................99

BREEDINGVISUAL SEXING.............................................................................................................................................................................100Colour .............................................................................................................................................................................................................................100Size ......................................................................................................................................................................................................................................100Femoral and Preanal Pores .........................................................................................................................................................101Hemipenal Bulges ......................................................................................................................................................................................101Paracloacal Spur Structures ......................................................................................................................................................101

OTHER SEXING TECHNIQUES .............................................................................................................................................101Hemipenal Probing .................................................................................................................................................................................101Hemipenal Popping................................................................................................................................................................................102Hemipenal Transillumination .................................................................................................................................................103Hemipenal Observation ..................................................................................................................................................................105Hemipenal Plug Observation .................................................................................................................................................105Hemipenal Palpation ............................................................................................................................................................................106

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 .................................................................................................................................................................115Determining Egg Viability ............................................................................................................................................................116

ARTIFICIAL INCUBATION ...................................................................................................................................118

INCUBATION FACILITY ...................................................................................................................................................................118

CONTAINERS .....................................................................................................................................................................................................119 HEATING ...................................................................................................................................................................................................................120

TEMPERATURE CONTROL .........................................................................................................................................................121

INCUBATION MEDIUM ....................................................................................................................................................................121Vermiculite .............................................................................................................................................................................................................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

HATCHLING CARE ..................................................................................................................................................................126

FEEDING ...................................................................................................................................................................................................................126 Feeding Frequency ..................................................................................................................................................................................127 Supplementation ........................................................................................................................................................................................127 LIGHTING ................................................................................................................................................................................................................127 HOUSING .................................................................................................................................................................................................................127 HEATING ...................................................................................................................................................................................................................127

COMPATIBILITY ...........................................................................................................................................................................................127

COMMON DISEASES AND DISORDERSDISCLAIMER ............................................................................................................................................................................................128

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

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

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

NAIL, TOE AND LIMB DISORDERS...................................................................................................138

EYE DISORDERS .............................................................................................................................................................................139EYE TRAUMA.....................................................................................................................................................................................................139PHOTOKERATOCONJUNCTIVITIS ...............................................................................................................................139PRIMARY BACTERIAL EYE INFECTIONS ..........................................................................................................139

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

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

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

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

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

SPECIESBLUE-TONGUED AND SHINGLEBACK SKINKSPRONUNCIATION .....................................................................................................................................................................................154

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

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

IN THE WILD .....................................................................................................................................................................................169DISTRIBUTION AND HABITAT ...........................................................................................................................................169

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

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

FEEDING ..........................................................................................................................................................................................................174

BREEDING....................................................................................................................................................................................................175BREEDING RECORDS FOR BLUE-TONGUED SKINK SPECIES ......................................178HYBRIDISATION AND COLOUR VARIANTS .................................................................................................179 LONGEVITY .........................................................................................................................................................................................................182ACKNOWLEDGEMENTS .........................................................................................................................................182

BURROWING SKINKSPRONUNCIATION .....................................................................................................................................................................................183

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





FEEDING ..........................................................................................................................................................................................................196

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

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

CREVICE SKINKS AND THEIR ALLIESPRONUNCIATION .....................................................................................................................................................................................201

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





FEEDING ..........................................................................................................................................................................................................220

BREEDING....................................................................................................................................................................................................221

BREEDING RECORDS FOR CREVICE SKINKS AND THEIR ALLIED SPECIES ...................................................................................................................................................................224

HYBRIDISATION AND COLOUR VARIANTS .................................................................................................225 LONGEVITY .........................................................................................................................................................................................................226


FOREST AND WATER SKINKSPRONUNCIATION .....................................................................................................................................................................................227

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


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

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

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

STATUS ........................................................................................................................................................................................................................236


FEEDING ..........................................................................................................................................................................................................238

BREEDING....................................................................................................................................................................................................239

BREEDING RECORDS FOR FOREST AND WATER SKINK SPECIES .......................241



PRICKLY FOREST SKINK

PRONUNCIATION .....................................................................................................................................................................................243

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


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


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

STATUS ........................................................................................................................................................................................................................247


FEEDING ..........................................................................................................................................................................................................249

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


RAINBOW SKINKSPRONUNCIATION .....................................................................................................................................................................................252

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




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

FEEDING ..........................................................................................................................................................................................................272

BREEDING....................................................................................................................................................................................................273INCUBATION AND HATCHLING DEVELOPMENT ..............................................................................274BREEDING RECORDS FOR RAINBOW SKINK SPECIES ............................................................274HYBRIDISATION AND COLOUR VARIANTS .................................................................................................274 LONGEVITY .........................................................................................................................................................................................................274


SAND SWIMMERSPRONUNCIATION .....................................................................................................................................................................................275

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





FEEDING ..........................................................................................................................................................................................................288BREEDING....................................................................................................................................................................................................289INCUBATION AND HATCHLING DEVELOPMENT ..............................................................................290BREEDING RECORDS FOR SAND SWIMMER SPECIES .............................................................291HYBRIDISATION AND COLOUR VARIANTS .................................................................................................291 LONGEVITY .........................................................................................................................................................................................................291


SLENDER BLUE-TONGUED AND PINK-TONGUED SKINKSPRONUNCIATION .....................................................................................................................................................................................292

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





FEEDING ..........................................................................................................................................................................................................306

BREEDING....................................................................................................................................................................................................307BREEDING RECORDS FOR CYCLODOMORPHUS SKINK SPECIES .........................308HYBRIDISATION AND COLOUR VARIANTS .................................................................................................308 LONGEVITY .........................................................................................................................................................................................................309


SMALL TERRESTRIAL SKINKSPRONUNCIATION .....................................................................................................................................................................................310

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


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


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

STATUS ........................................................................................................................................................................................................................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


STRIPED SKINKSPRONUNCIATION .....................................................................................................................................................................................331

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


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


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

STATUS ........................................................................................................................................................................................................................340


FEEDING ..........................................................................................................................................................................................................342

BREEDING....................................................................................................................................................................................................343

INCUBATION AND HATCHLING DEVELOPMENT ..............................................................................344

BREEDING RECORDS FOR STRIPED SKINK SPECIES .................................................................344



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

BIBLIOGRAPHYPRINTED LITERATURE......................................................................................................................................................................347ONLINE RESOURCES ..........................................................................................................................................................................350

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

Carlia pectoralis

S EI

PPER

• Theskinshouldshedcleanly.Retainedshedsmaynotbesignificantinasingleindividualbutifmultiplespecimenswithintheenclosurehaveproblems,itmayindicateoverlyhotanddryconditions.

• Inspect the tail—is it theoriginalor amodified tail?Amodified tail isusuallydefinedbyasignificantchangeinthetailcolourationandsurfacefeatures.Amodifiedtailisnotasignificantissue but some keepers require a perfect tail on a specimen. Amodified tailmay indicatefightingbetweenindividuals,roughhandling,wildoriginsorheatorcoldstress.Anindividualwithtailchangesisnolesshealthythanonewithanormaltail—butitmaydemandalowerprice.

• Checkforsurfaceparasites.Inspecttheeyesocketsandarmpitsforredmites.Althoughtheseparasitesarenonpathogenic,theycanbeunsightly.Theyoftenoccurinspecimenshousedinoutdoorenclosures,inenclosureswithnaturalfurnishings,suchasleaflitter,andinwildcaughtspecimens.

• Determineiftheindividualhasbeensexed.Asktheselleraboutthesexingmethodthathasbeenusedand,ifpossible,requestthesexualfeaturesbedemonstratedtoyou.

• Inspecttheskink’senclosure.Noteiftheconditionsarecleanandtidyoriftheoccupantsareovercrowded.

• Observe thehealthofother skinks in thecollection.Note if the sellerappears topossessagenuineknowledgeofthespecimensinhisorhercare.

HANDLING AND HYGIENEThe use of correct handling techniqueswhen managing lizards is necessary topreventinjurytothelizardandtoyourself,the handler. Most specimens employanti-predator mechanisms such as taildropping—knownastailautotomy.Theyaremoreatriskofinjurywhenemployingthesemethodsthanyou.

Large specimens may deter handlersby inflicting pain upon the aggressorthroughbitingorscratching.

Correcthandlingtechniqueswillavoidsmall lizards employing anti-predatormechanismsandreducetheriskofinjuryinflicted by large specimens. Followingarethespecifichandlingissuesassociatedwithskinksandtechniquesthatmaybeenactedtoavoidproblems.

Skinkspossesveryfewactivedefencemechanismsotherthanbiting,urinationordefecation.Thelatter isalmostacertaintywithsomespecies—particularlyEremiascincus—whereaslargerspecieswillmorecommonlyurinatewhenhandled.

Bitesbymostsmallskinksareoflittleconcern—thatis,iftheymanagetobiteatall—however,the pressure exerted by medium and large specimens can be quite surprising. Skinks aretenaciousbiters.Althoughtheir teethare rarelysharpenoughtocut theskin, theycancrushsnailshellswiththeirbite.

Ifyoudobecomethevictimofabite,attemptstoremoveaskinkcanmerelyaggravatethesituationand result inafirmerbite. Inmostcases,yourgripon theskinkshouldbe released,

D B

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Cyclodomorphus gerrardii. Most skinks have the ability to drop their tails at predetermined separation points

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 LIGHTINGThe 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.

Commercial ‘clamp lamp’ from IKEA™ Using a mounting block to attach a lamp to a glass surface

D B

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D B

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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 LightsOften 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 LampsThese 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.

D B

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N

Compact UV-B lampsCompact UV-B and reflector

D B

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N

D B

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NEC-T10™ black light and UV-B tubes

BREEDINGVISUAL SEXINGThe 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.

ColourMany 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.

SizeThere 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.

D B

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D B

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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

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 SPECIESTerrestrial 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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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 CONTROLAn 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 MEDIUMIncubation 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.

A commercial Hovabator™ poultry incubator being used for reptile eggs

A commercial Kimani Reptihatch™, a quality reptile specific incubator

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COMMON DISEASES AND DISORDERSDISCLAIMERAlthough 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 you if you ever seek advice from a non-

reptile 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

OBESITYLike 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

Basic anatomy of a skink Lampropholis delicata

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SEXINGBlue-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

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

Head of a typical male Tiliqua scincoides intermedia

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Head of a typical female Tiliqua scincoides intermedia

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. Populations in higher altitude areas are generally

darker, presumably to aid in thermoregulation. The Shingleback Skink T. rugosa varies dramatically in some populations.

Albino Tiliqua scincoides scincoides

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Albino Tiliqua nigrolutea

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Calico (Piebald) Tiliqua nigrolutea

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Patternless Tiliqua nigrolutea

DESCRIPTIONADULTS 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.

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.

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

Other species have a more subtle beauty, such as Lygisaurus foliorum

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COMPATIBILITYSand 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 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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Sneak preview of A Guide to Australian Skinks in Captivity

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