The keeping of pet snakes, lizards and chelonians (shelled reptiles) is still a relatively new hobby and many pet owners start from a high level of ignorance about their pet. Many do not even know which species of reptile they have bought or the correct diet and housing needs for the pet. Consequently poor husbandry is a major factor leading to malnutrition, debilitation and illness in pet reptiles.
All reptiles are ectothermic, meaning they are unable to generate metabolic heat and rely instead on the temperature of their environment. This basically means they draw their heat from the environment and not from their food. An advantage of this is that they need not waste energy maintaining body temperature--consequently most reptiles have a much slower metabolism with a metabolic rate only 25-35% that of mammals.
As ambient environmental temperature plays a vital role in reptile metabolism, food gathering and digestion, pet owners must provide the correct thermal range in captivity. This thermal range will depend on whether the animal comes from a temperate, subtropical or tropical climate. The majority of reptiles come from the tropics where it is warm all year round. Those that come from cooler climates have to hibernate when the temperature drops. Diurnal temperatures for tropical reptiles range from 26-37°C while temperate reptiles need a range of 24-29°C. Exact thermal requirements for each reptile species are available from reference books.
Due to their need for constant heat, reptiles must be kept contained either in a vivarium or heated enclosure. The vivarium should be rectangular to allow for a temperature gradient (i.e., hot end and cool end) and as large as possible to avoid problems with dominance and bullying. Territorial males tend to get more access to food and heat, allowing both increased food intake and more efficient digestion. The minimum requirement for lizards is three times the animal's length and two times its width. Arboreal (tree living) lizards like the iguana need increased cage height at 2-3 times the animal's length.
The design of the tank can be chosen from two approaches. The minimalist sterile tank with newspaper and bare essentials (as in for example a hospital tank) or a more aesthetically pleasing environment with major emphasis on enriching the pets surroundings. The advantage of this naturalistic tank design is a less stressed, leaner and healthier reptile. The disadvantage is that cage hygiene may suffer and impactions can occur from the reptile ingesting the substrate.
Cage furniture should be supplied according to the animal's needs. Arboreal reptiles like the iguana and chameleon need branches and foliage while terrestrial animals like tortoises and geckos need shelters. Secretive animals like the royal python need hidey holes as they like to eat in dark privacy. It is essential that tanks for snakes are secured with locks as they are notorious for their ability to wriggle out through tiny crevices and end up days later in a neighbour's apartment!
Heating should be provided to maintain the POTZ (Preferred optimum temperature zone). This is the thermal range of the reptile's natural habitat at which it functions optimally and has a maximum immune response. This can be provided by a heat lamp or heat pad or both. The heat pad should not occupy more than 30% of the tank and there must be no direct contact between either the heat pad and heat lamp as thermal burns are common. Heat pads should be placed under or attached to the side of the vivarium and heat lamps should be protected by wire mesh. Hot rocks are not recommended. A thermometer should be placed at each end of the tank to give accurate temperature readings.
The type of heating will depend on whether the reptile is a heliotherm or a thigmotherm. Heat lamps are best for heliotherms--these are reptiles which derive radiant heat from the sun and include diurnal species that bask in the sun. Heat pads can be used for thigmotherms--these include the nocturnal (e.g., leopard gecko) and crepuscular species that obtain their heat via conduction.
All diurnal reptiles need visible daylight and the photoperiod will depend on their natural habitat. Temperate reptiles should have 13-15 hours light in summer and only 9-12 hours in winter. Providing too long a photoperiod can lead to ovarian follicle problems and obesity.
Ultraviolet light is important for reproduction and Vitamin D absorption. Lack of UVB range leads to lack of vitamin D and subsequent nutritional osteodystrophy (metabolic bone disease). UV lights must be provided and located within 30cm of the reptile's basking area for maximum effect. They should be changed every 6 months. Traditionally UVB lights were fluorescent (tubular) but incandescent bulbs which provide both heat and UV light are now available. However as these can get very hot they can only be used in larger enclosures. Natural sunlight is the best source of ultraviolet light of all but must be unfiltered as UVB cannot penetrate through glass.
Humidity is very important to aid shedding (ecdysis) and prevent dehydration. The relative humidity for each species is available from reference books and a hygrometer is essential to give accurate readings. Humidity can be provided by mist spraying, water features, shallow water dishes or humidity chambers in focal parts of the tank. Live potted plants and moistened substrate would also help. Increasing humidity must not however be at the expense of poor ventilation as this will only lead to the buildup of bacteria and fungal problems.
The floor material is an important consideration for terrestrial or burrowing species, Newspaper, reptile mats and Astroturf are easy to keep clean but not aesthetic.
Coarse bark chips, wood chips, sand and stones are commonly used to produce a more naturalistic terrain. Food should be served in a dish to avoid the risk of the reptile ingesting the substrate. Sand (even so called 'calcium sand') is a common cause of impactions in juvenile or sickly reptiles.
Water bowls should be washed and disinfected daily to avoid Pseudomonas infections. Spot cleaning should be performed daily. Tanks should be cleaned and disinfected weekly. Gloves should be worn for tank cleaning and waste material must be kept well away from any food producing areas. The best disinfectants are quaternary ammonia compounds (e.g., Arklens / F10), dilute hypochlorites and iodophors.
Routine Health Care
The owner should keep records of feeding frequency, shedding and weight. A yearly veterinary examination is recommended with faecal parasitic examination. Annual blood for haematology / biochemistry tests may be needed.
When a new reptile is introduced it should be isolated and quarantined for at least 6 months during which time three faecal samples should be checked. New arrivals should also be checked thoroughly for mites as these are a common carrier of bacteria and viruses.
The diet of the reptile will depend on whether it is omnivore, herbivore or carnivore. Carnivores have a short simple gastrointestinal tract while herbivores have a large colon for fermentation of fibre.
Carnivores eat a diet high in animal protein and fat and the only carbohydrate is from the gut of their prey. All snakes are carnivores and are fed mainly rats and mice in captivity. As a general rule the smaller the snake the smaller the prey with juvenile snakes being fed pinkies (neonatal) mice. As freshly killed prey has the same quality as live prey it is not recommended or humane to feed live prey. Frozen food is acceptable although owners should be aware that after 6 months there is deterioration in taste, texture, smell and nutrients. Snakes should never be fed from the hand as they may inadvertently learn to strike the hand. A feeding tongs should always be used.
Many lizards are insectivores and in captivity the diet usually consists of crickets, locusts, mealworms and waxworms. Most invertebrates have an exoskeleton of chitin that is low in calcium. This deficiency can be rectified by 'gut loading' i.e., feeding the insects after purchase with calcium rich foods. Insects should also be dusted with calcium powder before feeding at least twice weekly and then hand feed to the reptile to prevent wastage.
Herbivores include most terrestrial tortoises and lizards like the green iguana, chuckwalla and uromastyx. They need a diet high in cellulose, calcium and vitamin A and low in fermented sugars and fats. Herbivores normally eat daily and can be fed a variety of chopped dark green leafy vegetables. Tropical species can also be fed some fruit. As herbivores are very visual reptiles, bright coloured foods of red, yellow and orange colour are readily accepted. All food should be well washed and fit for human consumption.
Omnivores derive their energy from a mixture of protein and fats as juveniles with more carbohydrate and fibre as adults. Many species like bearded dragons and aquatic turtles eat mainly animal protein when juvenile but become more herbivorous when older.
The frequency of feeding will depend on the species and size. Rapidly growing young lizards like bearded dragons and chameleons need to be fed twice daily. Chelonians and lizards usually eat daily or every other day. Small snakes feed about twice weekly while large snakes feed only every 2-4 weeks. Reptiles need the correct environmental temperatures to digest their food--if they are kept at sub optimal temperatures they may become anorexic or regurgitate.
This will vary with species--chameleons in the wild sip dew off leaves so will not drink from a water bowl in captivity. They can either be misted with a warm water spray twice daily or provided with a drip feed water system which allows water to drip onto foliage into a collecting water bowl beneath. Tortoises prefer to immerse their head while drinking so should be provided with a large shallow tray. Many snakes like a water dish in which they can soak so a large dog bowl or cat litter tray filled with water should be provided.