Reptiles are cold blooded vertebrates who are members of the class Reptilia. Living reptiles comprise turtles, crocodiles, lizards, snakes and rhynchocephalians. They belong to the tetrapod vertebrate’s category, meaning that they have four legs or are descended from four legged ancestors.
From turtles to snakes, reptiles make great pets as many find them surprisingly cute. Although we know that they make interesting pets, not much is known about if the nutritional needs of reptiles are met by their pet owners. But it is important to make sure that your scaly friend receives adequate nutrition since there are not many resources available on reptile food.
A number of things can affect the feeding behaviours of reptiles, from temperature and humidity, to stress, cage furniture and nutrition intake. The physical conditions of the reptile enclosure and sufficient quantity of feeding areas (if enclosure is shared with other reptiles) are important in encouraging adequate feeding habits.
Reptiles are fed a variety of prey, including rabbits, rats, mice, small birds, larvae, and insects. It’s recommended that prey should be sourced from commercial breeding centres, and offered as dead to reptiles, to prevent injury to the predators.
Knowing the reptile species’ habits in the wild is essential and relevant to informing on what foods and nutrient levels are appropriate for their diet. Providing two or more prey species for feed is beneficial in delivering a wider variety of nutritional benefits, as well as limiting dependence on a single prey species (which could present issues if the specific species becomes difficult to obtain), however this is dependent on what is nutritionally appropriate for the specific predator’s needs.
Categorised in four groups
Reptiles are categorised in four groups, carnivores, insectivores, herbivores or omnivores. Carnivores are relatively easy to give a balanced diet and less likely to have nutritional deficiencies, since they eat the whole animals, which aren’t in short supply.
They should be fed frozen, thawed or freshly killed prey animals. Feeding thawed food is especially beneficial to reptiles such as snakes, who may detect small temperature changes, as it encourages and stimulates reluctant feeders to eat.
Insectivores include animals that are commonly fed insects including crickets, mealworms, wax worms and inch worms. It’s recommended to feed these reptiles on a high calcium diet and to stick with well-known brands, whilst dusting crickets and mealworms with vitamins (containing D3) and calcium (with no additional vitamin D).
Some insectivores may also eat pinkie mice, wingless fruit flies or earthworms for additional nutrients, and others have unique specialised diets that may be difficult or impossible to provide regularly (for example the horned lizard needs a specific species of ants), in which case they should not be purchased and kept in captivity.
Herbivores require high fibre diets, with 90 to 98 percent of calories from plants, and should be fed a mixture of dark leafy greens with vegetables and fruits added. One way this can be provided with fresh grass or grass hay.
Most herbivores (and all omnivores) require an additional protein source, which may include hard-boiled eggs (with the shell), trout chow, tofu, alfalfa pellets, and cooked white meats. Feeding too much animal protein to herbivores can lead to kidney disease, so should only be done in moderation (once or twice a week).
The most important nutrient
Water is the most important nutrient for reptilians. Knowing the specific requirements of the reptile when it comes to water containers is pertinent, for example some reptiles won’t drink from bowls, and instead need mist sprayed on plants or the side of the cage, or even water dropped on a leaf.
Water containers should be deep enough to bathe (necessary to aid the proper shedding of skin for some reptiles) and shallow enough to exit easily and must be cleaned regularly and disinfected weekly.
Reptile food must contain all the essential amino acids to demonstrate biological value and provide an adequate energy source. Essential fatty acids are also crucial for cellular integrity, but it’s important to not feed too many to avoid obesity. Carbohydrates and fibre are important for herbivores for rapid energy production.
The key vitamins needed in reptile food are (fat-soluble) Vitamin A, D, E and K, as well as (water soluble) B vitamin complex and vitamin C. Another possibility for providing the necessary vitamin D absorption in the months where exposure to unfiltered natural sunlight is limited ultraviolet light.
An important consideration when feeding reptiles prey is preventing disease and the transmission of parasites. Paying attention to the freezing and thawing process in storing food is key. When freezing rats and mice, ensure the freeze storage conditions are optimal, keeping the temperature at -20°C and in thick plastic bags to prevent deterioration and help maintain the animal surface texture to be similar to live animals. When Thawing, seal the food in a zip lock bag, and place it in water that is just warmer than the prey animal’s normal body temperature. Make sure to use a cooler and ensure water loss is minimal (hydration of prey is crucial).
Research is lacking
Research on the nutrient requirements of reptiles is lacking, so there is no official scientific justification for product superiority. Manufactured diets are potentially simpler and more economical compared to fresh produce and live prey diets.
That said, they might not have rational formulas and lack micronutrient concentrations from the manufacturer. So, when using commercial products, it is advisable to only get products that provide information on the formulations and specific nutrient requirements.