What Should I Feed My Turtle?
First, know what species you are feeding. Diet and every other facet of care is determined by the natural habitat of the turtle. For instance, River Cooters eat a diet primarily composed of plants, while Map Turtles prefer animal matter. American Box Turtles are omnivores who eat a little bit of everything. The Malayan Box Turtle should eat plenty of plants with just a little bit of animal matter, but the Chinese 3-Striped Box Turtle eats "meats" almost exclusively. The red-eared slider starts out life eating mostly bugs, worms and other invertebrates, but becomes more omnivorous as it matures. (Please note: The information on this page does not apply to tortoises, which often have highly specialized diets. For tortoise diet information visit the Tortoise Trust Website and this article on Tortoise Foods.)
Reproducing the natural diet as much as is possible will make your turtle happier and healthier. In the wild, turtles choose from among a variety of foods that are in season and available. Variety is one key to a good diet for your turtle. Calcium is the other important key. Supplementation isn't necessary if enough variety is used in the diet. (After all, no one provides vitamins for the wild turtles, and they tend to be healthier than captives.)
You can read about the complicated relationships between calcium, phosphorus, vitamin D3 and other elements at several websites. The point to remember is that phosphorus is in most of the foods that turtles eat. It is the calcium side of the ratio that demands attention. Providing calcium separately allows the turtle to decide when it needs more calcium. Cuttlebone, plaster block, boiled and crushed eggshells, and crushed oystershell can all provide calcium on demand. Just providing a good source of calcium is not enough, however. Dietary calcium is not properly utilized in the absence of vitamin D3. Turtles can manufacture D3 if provided access to UV-B rays from direct sunlight or a good reptile light (e.g. Reptisun or Reptile D-Light.) Or D3 can be provided in the diet through supplements like Rep-Cal. A few foods block the absorption of calcium because of their high oxalic acid content. It's important not to overuse these foods, but they may have some benefits as natural vermifuge agents. Some foods contain goitrogens that can lead to iodine deficiency if overused. (Providing cuttlebone can correct this problem too, as it contains trace iodine.) High levels of protein put an abnormal stress on the kidneys, and may be implicated in some shell deformities. It's best to avoid excessive use of meats intended for human consumption and other high protein food sources. When used sparingly as part of a varied diet, no harm is likely to result, but high protein meats should not be used as a staple. It is important to use a great variety of foods, and not overuse any one type. Remember that all plants provide protein too, so it is not difficult to get enough protein in the diet.
For many years, turtle hobby enthusiasts have resorted to following lists of "good" foods and "bad" foods. Turtles in the wild pay no attention to these lists. :-) They avoid difficulties that could arise from some of the so-called bad foods by eating them sparingly, as part of a great natural variety around them. When they feel the need for calcium, they seek out eggs from amphibians & birds, or gnaw on carrion bones, or even eat mineral-rich dirt and sand. When humans intervene in the lives of wild animals, they tend to over-analyze things, to the detriment of the animals. By avoiding foods on the "bad" lists, we cheat our animals of many nutritious menu items. For instance, cabbage is often forbidden because of the high goitrogen content. If you fed your turtle nothing but cabbage, and never let it have iodine in any other form, the turtle could indeed develop kidney problems and goiter. So just use cabbage as one of the many item on the menu, and provide cuttlebone for the iodine replacement. Rather than avoiding perfectly fine, nutritious foods such as spinach or broccoli, we should use everything in moderation. And always keep calcium available in a separate form (such as cuttlebone.)
There are very few foods that should be avoided of strictly limited.
1.) Reptiles do not utilize milk products at any stage of their lives, and lack the enzymes to break down lactose. So do not feed cheese, yogurt, or other dairy products to your turtles.
2.) Canned and other processed foods often are very high in salt and other preservatives. The effects of these things are not fully known, but they would not be part of a natural diet. It would be prudent to limit their use.
3.) Avoid candy, chocolates, breads, and any other refined sugars and flours, or other highly processed food-like products.
4.) Although some turtles are known to eat poisonous plants in the wild, the specifics of that behavior are not well studied. It is probably wisest to avoid the use of toxic plants in their habitats (i.e. poison ivy, rhubarb plants, avocado plants, etc.)
In general, however, it all comes down to variety. If you feed
just cantaloupe and crickets, there will be problems down the line. There's
nothing wrong with those foods. They're simply insufficient. If you feed
a wide variety of foods, the occasional use of cabbage, lettuce, or even
cooked beef heart will not cause problems. Further, feeding some foods that
are low calcium foods, or high in phosphorous or oxalates, will matter not
at all if a separate source of calcium (cuttlebones/ plasterblocks/ eggshells/
crushed oystershell) is always available. This is more in keeping with the
way turtles feed in the wild anyway. While some keepers carefully consider
the calcium/phosphorus ratio, turtles don't waste a precious second pondering
the chemical analysis of their food. If it's tasty and it's there, they'll
eat it! Later, they'll munch some carrion bones or birds' eggshells and
get caught up on calcium. It may be impossible for us to really "think
like a turtle" but we can at least try. Turtles fed a wide variety
of foods are happier and less likely to develop dangerous food fetishes.
Try *Many* of These Foods for Omnivorous Turtles
aquatic plants (duckweed, water lettuce, parrot feather, etc.), watercress, collards, turnip greens, red and green leaf lettuce, romaine lettuce, dandelion, chickweed, plantain weed, carrot tops, red clover, endive, fig leaves, grape leaves, sow thistle, tufted vetch
squashes, peas in the pod, okra, grated or sliced carrots, sweet potatoes
figs, grapes, blueberries, cantaloupe, blackberries, tomato, banana, strawberry, apple, citrus fruits, mango, kiwi, pumpkin-- all fruits are fine for occasional use
geraniums (Pelargonium species), Chinese Lantern (Abutilon hybridum not Physalis sp.), nasturtium, borage, hyssop, hostas, hibiscus, carnations, daylilies, petunia, pansies, chives, dandelion, rose and rose hips
silkworms, earthworms, crickets, snails, shrimp, slugs, waxworms, mealworms,
zoophobas, pinky mice (live or pre-killed), cooked chicken or turkey, boiled
eggs, cooked fish.
prepared turtle foods:
Commercial foods can be used as part of the diet--
Reptile Tri-Cal or Rep-Cal are the best calcium/D3 supplements by far.
A jar of Rep-Cal is rather expensive, but lasts a very long time. Tri-Cal
even comes in a handy shaker bottle. Use once a week. Vitamin supplements
may also be used.
The Tortoise & Turtle Feeding Manual, by A. C. Highfield
© 1999 Mary Hopson, Anchorage, AK
This information sheet may be freely copied and distributed.
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