Nutrition of Turtles and Tortoises

Turtles, tortoises and terrapins are all in the group known as chelonians. They all possess a shell. The term tortoise is usually used to refer to terrestrial turtles in the United States, but we do have a few that stay predominately on the land, but are referred to as turtles, for example, the box turtle and the North American wood turtle. As they are such a diverse group of animals, it would be expected that the different species would have widely diverse diets. Green sea turtles are largely vegetarian and consume primarily see grasses, and the other sea turtles are mainly carnivorous, feeding on jellyfish, crabs, sea urchins, fish, sponges and barnacles. Some land tortoises are vegetarian, and spend their days grazing and foraging. Box turtles eat a little bit of everything encountered, and they are considered omnivores, meaning that they consume lots of bugs and worms, as well as plant material. Water turtles begin life as meat eaters and as they mature, they begin to consume more and more plant material.

Correctly feeding your pet turtle or tortoise begins with knowing exactly what kind of chelonian you actually have. If you are unsure as to what kind of turtle or tortoise you actually own, check in an atlas, or ask a knowledgeable herper or breeder to help you in the proper identification. Once you know what type of chelonian that you have, feeding it becomes a lot easier.

Land tortoises, such as the African Spur-thighed (Geocholone sulcata), the Leopard (G. pardalis), Star (G. elegans), Red-footed (G. carbonaria), Yellow-footed (G. denticulata), Hermann's (Testudo hermanni), marginated (T. marginata), Russian (T. horsfieldi), Greek (T. gracea), Egyptian (T. kleinmanni) and Hinged-backed (Kinixys spp.) can all be fed primarily the same type of diet, although some are from tropical forests, others are found in grasslands, and yet others are from desert regions. Other rare tortoises, the Galapagos (G. elephantopus) and the Aldabra (G. gigantea) are giant tortoises that experienced herpers should maintain.

If at all possible, during warm weather, tortoises should be placed outdoors to allow them to graze, exercise and bask in the sun. Outdoor enclosures should be secure, with solid barriers (tortoises will try to get through barriers they can see through, so wire isn't the best barrier). Since tortoises like to dig, it is preferable to bury 6-18 inches of barrier to prevent escape. An outdoor enclosure should have shade and water, and should be secure to prevent possible predators (dogs, raccoons, opossums, etc.) and dangerous insects, such as fire ants, from injuring tortoises. Pesticides can poison tortoises and turtles, and toxic plants should be removed from the enclosure. The pen should be raked periodically, and any bits of metal, nails, pieces of glass or plastic or other debris should be removed.

Sunshine is vital for turtles and tortoises in order for synthesis of vitamin D to occur. If you are unable to place your pet chelonian outdoors (for example, if you live in an apartment), full-spectrum fluorescent lighting should be used as a light source over the cage (and it should be 12 inches or closer to the herp for proper utilization). Sunlight must be unfiltered by glass or plastic to provide the necessary ultraviolet light for vitamin D production, so don't think that placing a glass aquarium next to a window will do. That will not allow a chelonian to properly absorb the ultraviolet rays.

Tortoises should be fed a diet of about 95% vegetables. The majority of the veggies should be dark green leafy (collard, mustard, radish, turnip, kale, cabbage, dandelions, bok choy, broccoli leaves, clover, legumes, cut grass from your yard, and cut weeds). If you feed grass or weeds from your yard, make sure that no pesticides have been applied, and that weeds are non-toxic. Other vegetables that can be fed in lesser amounts include spinach, Swiss chard, red leaf, romaine, beet greens, thawed frozen mixed vegetables, peas, cauliflower, green beans, squash, green peppers, and clover. Hibiscus flowers and leaves, grape leaves, carnations, roses, nasturtiums and squash flowers are also relished. Alfalfa pellets can be soaked and offered. Prickly pear cactus pads (minus spines) can be fed.

Tortoises really seem to like fruits. However, fruits tend to be mineral poor and have an incorrect calcium:phosphorus ratio, so they should be offered as about 5% of the diet. Tortoises enjoy melons, grapes, apples, oranges, peaches, pears, plums, strawberries, raspberries, bananas (with the peel), mangos, papaya, prickly pear fruit and tomatoes.

Red and yellow-foot tortoises naturally consume more fruits than other tortoises, so the portion of fruit in the diet can be increased to 15-20%.

You may have seen commercial tortoise diets offered in pet stores. These can be soaked and offered as a small portion of the diet. I raise several species of tortoises, and I have been pleased with the quality of commercial diets, which I feed in addition to veggies and fruits. To avoid having a tortoise selectively choose only preferred food items, the daily diet should be chopped small enough so that the tortoise can't pick and choose. Daily, several dark green leafies should be offered, as well as some other veggies and a small amount of fruit. If you add tortoise chow to the mixture, you should not need to supplement with calcium or vitamins. If you don't use commercial chow, a calcium supplement may be lightly dusted over the salad daily, and a vitamin supplement can be lightly added every week or so.

Hatching turtles and tortoises should be fed daily, and adults can be fed every other day or three times per week. Fresh, clean water should always be available for them to drink and to soak in. For all species, the first year of life is very important, since they are growing rapidly during that time. It is vital that they receive a balanced diet to prevent bone and shell problems.

Box turtles should be fed a diet that is very different from the tortoises. Young box turtles will eat primarily animal material. As unappealing as this might appear to you, they should be offered earthworms, slugs, snails, beetles, millipedes, spiders, crayfish and grasshoppers. Chopped up pinky mice are very good for them. If you can't provide this type of diet, commercial box turtle chow might be the answer for you. This can be used as a good portion of the diet, but some worms and crawlies should still be offered.

Box turtles also will eat plant material, including mushrooms, tomatoes, strawberries, raspberries, and other fruits. Box turtles should eat about 50% animal proteins, and 50% plants (including 75% veggies and 25% fruits). Use the fruits and vegetables from the tortoise list as your guide.

Some box turtles are very finicky, and for those difficult pets, it might be better to offer a commercially prepared box turtle chow, and added animal and plant materials. They need lots of beta-carotene (a precursor of vitamin A) in the diet to prevent medical problems.

Aquatic turtles, while often plentiful in pet stores, are among the most difficult reptiles to correctly care for. Red-eared sliders, painted turtles, mud and musk turtles, map turtles, soft-shell turtles, snapping turtles, cooters, matamatas, Reeve's turtles and Asiatic box turtles all require clean, warm water for swimming. They will almost always eat their meals in the water. It is easiest if water turtles can be taught to eat their meals in a separate small container of water, because foods are the most common offender in fouling the water. By feeding in a small container of water, it is possible to maintain a clean habitat more easily. The water in the main tank should be filtered or changed regularly. There should be a place to allow a water turtle to completely climb out of the water to bask.

Aquatic turtles should be fed a variety of foods. Commercial floating food sticks can be used as a portion of the diet. Small turtles should be offered chopped earthworms, snails, slugs, shrimp in the shells, chopped up whole fish (frozen and thawed to kill parasites), chopped mice, and gut-loaded insects. Raw chicken, lean beef, liver and gizzards can be offered very sparingly. As water turtles get older, they will usually consume dark green leafy vegetables (see the list given for tortoises). They may also consume duckweed, anarchis, algae and some fruits. They should still be offered meats and floating sticks, as well.

Chelonians that are fed a diet too high in protein and other nutrients may develop shell abnormalities that will affect them for life. Tortoises fed exclusively primate chow, dog food or cat food will usually develop grossly deformed shells, especially the carapace (top shell). The shell may become domed and misshapen, which can affect the ability to walk and move normally. Severely overweight chelonians may actually have fat bulging out around the armpits and groin. This is unhealthy, as well. Rarely, a chelonian may develop goiter (a type of thyroid disease from lack of iodine) from a diet of almost exclusive cabbage.

It is very important that each species of turtle and tortoise be properly maintained at the correct temperature range for efficient digestion. Chelonians kept at the incorrect temperature will have problems properly digesting food, and they will be more prone to many diseases. In addition to being maintained properly, some species will naturally hibernate in given geographic areas. It can be beneficial to simulate this natural rhythm and allow certain tortoises to hibernate naturally. It is best to have a tortoise thoroughly evaluated by a vet familiar with hibernation prior to cooling one down for the winter. Sick, thin or heavily parasitized tortoises should not be hibernated.

It can be a real challenge to properly feed and care for chelonians. Since some turtles and tortoises can live for 50 years or more, it is vital that they receive a well-balanced diet for proper growth and development. For all species, variety is the key. Don't allow a chelonian to selectively consume only a few preferred food items. Vary the diet frequently, provide the correct environment, and have your chelonian examined by a herp veterinarian periodically, and your pet should live for a very long time. Come to think of it, add consulting your attorney to the list of things to do for your tortoise, so that you can provide for it in your will! Pick an interested young friend or relative to will your chelonian to, for, with excellent care, it might outlive your family!

Copyright 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
All Rights Reserved

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