Reptiles For Dummies

Transcription

1 Reptiles For Dummies Dr. Shane Simpson B.V.Sc. (Hons), GCM(VP), CMAVA Karingal Veterinary Hospital 328 Cranbourne Road, Frankston, VIC, 3199 P: F: Be it fear or fascination people have always had a thing for reptiles. Dinosaurs have long captured our imaginations and celebrities like the late Steve Irwin have brought reptiles into people s living rooms all around the world. Factors such as these mean that the number of reptiles being kept as pets seems to be increasing at an exponential rate. Consequently the number of reptiles being presented to veterinary clinics has and will continue to increase. If the thought of having to see a reptile in a consultation makes you weak at the knees then you are not alone. Amazingly many veterinarians would rather not see reptiles. For a minority it is due to fear...yes there are Veterinarians that are afraid of snakes! For all the others it is simply because they do not have the knowledge or experience in the field of reptile medicine and surgery. At Veterinary School we get little to no exposure to reptiles and so we graduate with no confidence in our abilities in treating these wonderful animals. Hopefully the following will provide you with some basic information for treating reptiles in your practice. Reptile Taxonomy It is important to know what reptile species you are examining because it has major implications to their temperaments, husbandry requirements, disease possibilities and in some cases whether their bite can kill you or not! There are approximately 7500 reptile species throughout the world. In Melbourne a veterinarian in general practice is likely to see less than 0.2% of this number of species. A simplified taxonomy of reptiles in Australia is shown in Figure 1. Some of the common species seen from each Order include: 1. Eastern Long Neck Turtle (Chelodina longicollis) 2. Jungle Carpet Python (Morelia spilota cheynei) 3. Coastal Carpet Python (Morelia spilota mcdowelli) 4. Diamond Python (Morelia spilota spilota) 5. Centralian Carpet Python (Morelia spilota bredlii) 6. Children s Python (Antaresia childreni) 7. Bluetongue Lizard (Eastern and Blotched) (Tiliqua scincoides ssp.) 8. Central Bearded Dragon (Pogona vitticeps)

2 Figure 1. Simplified Reptile Taxonomy in Australia In more specialised reptile practices other species such as assorted monitors and other lizards, crocodiles and various species of snakes would also be seen. Many reptile owners (or herpers as they often call themselves) have a somewhat cynical view of veterinarians and will often do a lot of research into finding a veterinarian that is competent with reptiles rather than just go to the local veterinary clinic... even in the case of an emergency! Once you have established what species of animal you are dealing with you should then gain some understanding of where it originates from e.g. is it a desert or tropical species? What is its natural habitat? I can recommend four books to aid in getting this information: i. A Complete Guide to Reptiles of Australia by Steve Wilson and Gerry Swan ii. Keeping and Breeding Australian Pythons edited by Mike Swan iii. Keeping and Breeding Australian Lizards edited by Mike Swan iv. The Australian Reptile Keepers series These are available through and

3 History Taking Getting an accurate history is one of the cornerstones of reptile medicine. Taking a history is like conducting a job interview... you have to ask the right questions! Areas to be questioned include: 1. Source i. Is the animal captive bred or wild caught? Wild caught animals sometime do not adjust to captivity and develop maladaptive syndrome when confined. Wild caught animals can also have higher internal parasite burdens. ii. Where did the owner get the animal? Pet shop, breeder, local or interstate. iii. How long have they had the animal? 2. Heat i. What type of heat source is used? ii. Is it a radiant or convective source? iii. It is controlled by a thermostat? iv. Does the enclosure have a thermometer? v. Where are the thermostat and thermometer positioned within the enclosure? vi. Does the client know the difference between a thermostat and a thermometer? vii. Are the heat sources guarded? 3. Light i. Is a UVB light available? ii. What type of visible light is available? iii. Where is it positioned in the tank in relation to the animals? iv. When was it last changed? v. Is there any glass between the light and the animals? vi. Do the animals have any exposure to natural sunlight? vii. What is the light cycle? i.e. How long is the light on for over a 24 hour period? 4. Humidity i. What is it in the enclosure? ii. Is it measured? i.e. Is there a hygrometer present? 5. Cage size i. Size? ii. Ventilation? iii. Materials that it is constructed of? iv. How often is it cleaned and with what? v. Are cage mates present? If so how many, what sex and what species? 6. Cage Furniture i. What items are in the cage? e.g. hides, rocks, branches, logs, plants etc. 7. Substrate i. What is it? ii. How often is it cleaned/changed? iii. Is it suitable for the species involved?

4 8. Feeding i. What is being fed? ii. How often is it being fed? iii. Where is the food sourced? 9. Water quality (for aquatic species) i. Is the water tested regularly and for what? ii. How much and how often is the water changed? iii. What form of filtration is in place? iv. Is the water heated and if so to what temperature? 10. Illness History i. How long does the owner think the animal has been sick? ii. Are any health records kept? e.g. Feeding, shedding, weight data Husbandry While it is vital to obtain a very detailed and specific history about the way the animal is kept, it is impossible to determine if there are any problems with the way the animal is maintained if you don t have an appreciation of how the animal should be housed in the first place! In addition, the vast majority of problems seen in reptiles are related to poor husbandry. The basic principles of reptile husbandry can be covered by the seven H s. Heat (and Light) Reptiles are NOT cold blooded. They are ectothermic meaning they regulate their body temperature by behavioural and physiological mechanisms rather than producing their own body warmth. Their body temperature is therefore dependent on the environmental temperature. All reptiles have what is referred to as an Active Temperature Range or ATR. This is the temperature range where reptiles are capable of normal, voluntary activity. Below this temperature reptiles will just simply shut down until the temperatures are more suitable. Each species of reptile has a different ATR. The Preferred Optimal Temperature Range/Zone (POTZ) or Preferred Body Temperature (PBT) refers to the specific temperature range selected by a particular species of reptile when presented with a thermal gradient. Each reptile species has its own POTZ and it is only when the animal is in its POTZ that its physiology is functioning at its best. It should be noted that the highest temperature in the enclosure the reptile can access is usually higher than the PBT. The PBT for a number of the commonly kept species is shown in the table below. Species PBT ( C) Eastern Log Neck Turtle Children s Python Carpet Python Diamond Python

5 Bluetongue Lizard Central Bearded Dragon Reptiles should therefore be exposed to temperatures that they would normally experience in the wild. Their enclosure should offer a range of temperatures within it to allow the animal to choose its thermal environment and therefore thermoregulate. This is achieved by having heat sources strategically placed within the enclosure. Two main types of heating are used by reptile keepers. These are radiant sources (e.g. lamps, ceramic heat emitters) and convective (e.g. heat mats, heat tapes and heat rocks). Different species of reptiles prefer different heat sources e.g. large snakes rely primarily on radiant heat where as small snakes like convective sources. Heat sources should be thermostatically controlled in order to avoid overheating. Some reptile owners do not recognise the difference between a thermostat and a thermometer. Thermostat readings are only a guide and they must be calibrated for individual enclosures using a thermometer. The temperature gradient is NOT a reading of the thermostat setting. Lighting for reptiles is a complex and often poorly understood component of husbandry by reptile owners. Ultraviolet light is essential for the synthesis of vitamin D 3 and calcium metabolism. Many of the common Australian species that are kept indoors need to have ultraviolet light provided with a wavelength of nm. This falls within the UVB range. There are many types of lights manufactured to provide this and some do it better than others. They need to be replaced as per the manufacturers guidelines as their UV light production decreases with time. In general most need to be replaced every 6 to 9 months. All reptiles should be provided with a natural day and night cycle of light and dark. Ensure that the reptile is not exposed to white light 24 hours a day. Exposing reptiles to natural, unfiltered sunlight for at least ½ hour 2-3 times per week is beneficial. Humidity Humidity requirements vary greatly between reptile species. An appreciation of where a particular species comes from will give a good indication. Desert species like Central Bearded Dragons need around 40% humidity where as far north Australian inhabitants such as the Green Tree Python obviously like it much more humid. Humidity can be controlled by altering the size of the water bowl. A heat mat under the bowl can be used to increase the humidity if required. Misting with a spray bottle may also be required. Humidity should be monitored using a hygrometer and the enclosure must be adequately ventilated. Hide To reduce stress levels all captive reptiles need somewhere to hide. Ideally several hide places should be provided within a cage and be situated in different locations. This will allow the animal to select its preferred location. Hides can include toilet rolls and small cardboard boxes through to plastic artificial rock hides that are commercially available.

6 Hygiene Good hygiene is essential for maintaining the health of captive reptiles. Owners should have a hygiene and maintenance schedule. The choice of an appropriate substrate in the enclosure is vital. Alternatives include newspaper, pelleted newspaper kitty litter, fine sand and many commercially produced substrates. It must be easily cleaned and should not be able to be ingested. Drinking water should obviously be fresh and free from faecal matter. Many reptiles have a habit of using their water bowls as toilets. The commonest cause of disease in captive aquatic turtles is poor water quality. The water should be regularly tested for ph, ammonia, nitrate and nitrite levels. It should be changed regularly and adequate filtration is a must. Suitable cleaning agents for reptile enclosures include F10 or a weak bleach solution. There are several other cleaning products available that are marketed for reptiles and they are likely to be satisfactory. Healthy Appetite Given there are over 7500 species of reptiles in the world it is not surprising that their diets are greatly varied. It is important to understand the appropriate diet for the species being dealt with. Bluetongue lizards and Central Bearded Dragons begin liking insects only but as they age they both develop a taste for fruits and vegetables. Small lizards can be fed daily while adult lizards are usually fed every 2-3 days. All Australian snakes are carnivores and as they grow from a hatchling their prey item s size can be increased through the various stages of pinkie, fuzzy, weaner and adult mice or rat. Hatchlings can be fed every 4-5 days while adult pythons can be fed every days. It is not unheard of though for large snakes to only feed once every 3 to 9 months Turtles will normally only eat in the water. It is preferable to feed all reptiles in a separate feeding enclosure where possible. This reduces the amount waste food in the enclosure and allows for snakes to be more easily handled. Never feed snakes together in the same enclosure. Never feed live rats and mice to snakes. Prey should be frozen for at least 4 weeks to remove parasites and for welfare concerns. Habitat It is common for reptiles to be house in too large an enclosure. If it is too big small reptiles may find it difficult to thermoregulate because it may be difficult to heat the enclosure adequately. Snakes should be able to stretch out to their full length. There are Codes of Practices available that give guidelines as to minimum sizes of enclosures. Handling Reptiles should not be over handled as this will cause stress though this is species dependent. Placid lizards such as Central Bearded Dragons are not fazed by handling whereas other species like Eastern Water Dragons will try an escape at the first opportunity. Snakes should not be handled for at least 3 days after eating due to the risk of regurgitation.

7 Hands should be washed prior to and after touching reptiles to limit the potential spread of disease and to be rid of any mammalian scent. A snake will instinctively strike if it smells a mammal. All reptiles brought into your clinic should be adequately contained. They should never be brought in draped over the shoulder and not in a container. This can be stressful for the animal, particularly if there are dogs and cats in the waiting room. It is also stressful for non-reptile owning clients! Clinical Examination As with all clinical examinations a thorough and systematic approach is needed. It is however important to be aware of the unique anatomy and variety of the class Reptilia. Here are some specific tips, tricks and points about the handling and physical examination of reptiles. Turtles. i. Turtles are generally easy to handle. ii. They should be weighed and measured. A tailor s tape can be used to take a straight carapace length (SCL). iii. Turtles are restrained by holding the caudal or lateral edge of the carapace. iv. Watch the mouth of short-neck turtles (Emydura spp.) as they have a habit of biting and are usually more mobile than their long-neck counterparts. Turtles do not have teeth but they have a sharp beak. They tend not to let go once they have latched on. v. There are glands located on the bridges of the shell that discharge a pungent fluid that stays for hours if it gets on your hands. vi. Agitated turtles will often urinate when picked up. vii. All except one Australian freshwater turtle are side-necked or pleurodirous. This makes it often very difficult to straighten their neck for examination. viii. The central groove in the carapace deepens with age. ix. The mouth can be difficult to open. A guitar plectrum or a corner of radiography film can be used to gently lever the mouth open. x. Coelomic cavity can be palpated via the prescapular and preformal fossas depending on the size of the patient. Lizards. i. Some species of reptiles may drop their tails when handled (e.g. small skinks, including Bluetongue lizards, geckoes). ii. Certain species like Eastern Water Dragons and monitors are more likely to bite. Avoid this as it REALLY hurts! Control the head behind the mandible with the thumb and index finger while holding the rear legs up against the tail or just below the pelvis with your other hand. iii. Young Eastern Water Dragons can be hypnotised by laying them on their backs and stroking their abdomens. iv. Skin tenting, as in mammals, may indicate dehydration. v. Like turtles, examination in the mouth can be difficult.

8 vi. Some species, particularly monitors will scratch and whip their tails in defence. vii. Large fat pads can be felt on either side of the abdomen in many dragon species. viii. It is difficult to perform coelomic palpation in large skinks versus dragons due to their muscle tone and inelastic skin. Snakes. i. Pythons of all sizes may bite and constrict, even the ones the owners say have never bitten before! ii. Venomous snakes should only be handled after being accurately identified and only if the handler is experienced and known to be competent by the Veterinarian. iii. Never put your hand in a snake bag without knowing EXACTLY what is in it! iv. Snakes should be weighed and its movements closely observed. A snout-to-vent length (SVL) can be taken. v. The snake s head can be controlled in a similar fashion to that of a lizard. Because snakes only have one occipital condyle, dislocation at the joint can occur more easily than in other animals if the head is held too firmly. To prevent this allow your hand to move as the snake moves its head, with only slight resistance. vi. Restraining the head will often make them struggle, whereas gently handling them by supporting the body tends to make them relax. vii. Auscultation with a stethoscope is a waste of time. viii. Snakes will excrete voluminous faeces and urates if distressed. This is particularly so for Diamond Pythons. ix. A snake that feels threatened may wrap the end of its tail around the consult table or other furniture. They can be VERY difficult to dislodge. x. Scrub Pythons and Water Pythons are usually difficult to handle. Common Problems in Captive Reptiles Unfortunately captive reptiles get sick and injured. The following is a brief introduction to some of the common conditions seen and some ideas on how best to treat them. 1. Anorexia Anorexia is not a disease but a possible sign of a problem. There are many reasons for a captive reptile to become anorexic and not all of them are due to illness. Particular attention must be made to obtaining a thorough history and assessment of the heating in the enclosure before treatment is instituted if necessary. 2. Stomatitis This condition is most commonly seen in pythons but can occur in lizards and turtles. Affected snakes are usually inappetant. In the early stages it presents with mild petechial haemorrhages in the gums, mild swelling and possible drooling. As it progresses the swelling worsens, abscesses may form and underlying bone may be exposed. Severe cases may need surgical debridement. The cause is multifactorial and usually indicates some husbandry related issue. The animal should be checked for other problems as stomatitis often occurs secondary to other problems.

9 3. Mites The snake mite, Ophionyssus natricis, is a common external parasite of pythons and certain lizard species. They are blood-sucking mites that can cause general dermatological changes and have been linked to the transmission of a number of diseases. They can be difficult to eliminate. 4. Internal Parasites Ascarids, cestodes and other internal worm infestations are common in captive reptiles. Coccidia is also a common problem in lizards, particularly Central Bearded Dragons. 5. Ventral Scale Rot or Blister Disease This is a common problem seen in pythons that are exposed to high humidity, inappropriate substrate, suboptimal temperatures or poor hygiene. In the early stages small blisters appear on the ventral scales. As the problem progresses these scales may peel away in patches and become infected. Treatment requires correctly the husbandry problem, systemic antibiotics and topical medications. 6. Abscesses Abscesses are very common in captive reptiles. They may form after haematogenous spread of pathogens or a more direct cause such as a wound. Treatment most often requires surgical curettage and antibiotic therapy. 7. Metabolic Bone Disease This is the most common nutritional deficiency affecting lizards and turtles. Young lizards often twitch or have paresis in the hind limbs and tail. Some come in lame after breaking a leg because of poor bone density. It is caused by a deficiency of calcium in the diet, a lack of exposure to UVB light or a combination of both. Snakes are generally not affected because they are fed whole mammalian prey. Treatment requires calcium supplementation and correction of any lighting deficiencies. 8. Respiratory Disease Reptiles lack a diaphragm and have a varied and unusual respiratory system that makes them prone to respiratory disease. Pythons often present with open mouth breathing and a respiratory wheeze. Lizards will often show upper respiratory signs such as sneezing and blephritis. Turtles will often have buoyancy issues. 9. Obesity Many reptiles are overfed and overweight. Certain species of reptiles such as Central Bearded Dragons and Children s pythons are prone to obesity. Being fed too much, too often or too much high fat food can cause obesity. In addition captive reptiles do not tend to get exercised and have their food handed to them with little or no work. Obesity can cause hepatic lipidosis that just as in feline patients can be a difficult and frustrating condition to treat. 10. Reproductive Problems A range of reproductive diseases are seen in reptiles. Follicular stasis and egg binding are common. Causes include injury, debilitation, lack of an appropriate substrate to lay the eggs, suboptimal temperatures, calcium deficiency, obesity and poor muscle tone.

10 11. Shell Rot Shell rot is a seen in turtles where water quality is an issue. Areas of the shell soften and become necrotic. These areas need to be curetted clean and a topical antibiotic ointment applied. The turtle may need to be kept out of the water for a period of time to let the shell dry out. 12. Hypovitaminosis A This occurs in turtles that are fed exclusively frozen fish diets. It presents as swelling of the eyelids caused by squamous metaplasia of the epithelium. In severe cases the respiratory system is affected. Treatment requires vitamin A supplementation and correction of the dietary deficiency. 13. Burns Reptiles have a penchant for burning themselves. Something in their physiology seems to make then unable to sense when they are burning. Combine this with putting them in close proximity to heat lamps and other heat sources and you are bound to get problems. Burns can be very severe and often need aggressive treatment. Antibiotics, analgesia and debridement are often required. 14. Shell Fractures Turtles are often presented after being hit by cars or attacked by dogs. Each case should be assessed for internal injuries and the extent of shell damage. The fractures should be treated as open wounds and fibre glass should be avoided. 15. Dysecdysis Problems shedding skin is a very common condition that affects snakes and to a lesser extent, lizards. Left untreated it can result in bacterial dermatitis that ultimately can cause septicaemia. In lizards retained shed can constrict around the toes resulting in the loss of the digits. Dysecdysis is often caused by a lack of humidity. Conclusion Reptiles are an incredibly interesting group of animals. They are becoming an increasingly popular pet and veterinarians need to have at least a basic understanding of their husbandry, handling and the diseases that they commonly present with in order to provide at least basic veterinary attention. References 1. Bradley T. Basic Reptile Handling and Restraint Proceedings of the Western States Veterinary Conference, Las Vegas, USA. 2. Cannon M. Taxonomy and Identification of Common Reptile Species Proceedings of the Australian Veterinary Association Conference, Canberra, Australia. 3. Carmel B. Rapid Reptile Results Proceedings of the Australian Veterinary Association Conference, Hobart, Australia. 4. Johnson R. Husbandry and Its Relationship to the Health and Welfare of Captive Reptiles Proceedings of the Australian Veterinary Association Conference, Canberra, Australia. 5. The Healthy Reptile Consultation (How to Look Like a Reptile Vet) Proceedings of the Australian Veterinary Association Conference, Canberra, Australia.

11 6. Johnson R. Some Commonly Occurring Conditions in Captive Reptiles Proceedings of the Australian Veterinary Association Conference, Canberra, Australia. 7. Johnson R. Physical Examination and Diagnosis in Captive Reptiles Proceedings of the Australian Veterinary Association Conference, Canberra, Australia. 8. Mader D. Reptiles Knowing the Normal Proceedings of the Western States Veterinary Conference, Las Vegas, USA. 9. Simpson M. Some Commonly Occurring Conditions in Captive Reptiles Part Proceedings of the Australian Veterinary Association Conference, Canberra, Australia. 10. Simpson S. Reptile ER. AEC Seminar Acknowledgements Thank you to Damian Goodall from Eye For Nature Wildlife Photography for allowing me to use his stunning photography in my presentation. Check out his website at