Health and Husbandry

A Gulf Coast Turtle and Tortoise Society Care Sheet

By Dr. Robin Scott; edited by Julie Young - GCTTS Member

Table of Contents

The Body Craves Calcium
The Problem with Supplements
The Role of Vitamin D
Diseases Caused by Calcium Deficiency
Problems with the Kidneys
Dietary Problems
Miscellaneous Feeding Information


This article is an abstract of the talk given by Dr. Robin Scott, DVM at a meeting of the Gulf Coast Turtle & Tortoise Society.

Dr. Scott's talk was about the proper feeding of chelonians and diseases associated with poor nutrition. She began her talk by defining the three general categories of chelonians and noting the diet each group generally follows: Tortoises - herbivore (eat plant material) Box Turtles - omnivore (eat any-and-everything, half plant material and half meat) Water Turtles - carnivore (eat meat)

All turtles and tortoises need a proper ratio of calcium and phosphorus in their diets, but in captivity, this ratio is difficult to maintain. Many animals fall into ill health due to an improper ratio of these minerals. The culprit is almost always a poor diet.

A normal mineral balance in a turtle's body would be two parts calcium for each one part phosphorus. That means for every two molecules of calcium floating through the animals bloodstream, there would be one molecule of phosphorus. But often, proportions become imbalanced and an overabundance of phosphorus develops. When the body recognizes this, it tries to regain its correct balance. The body starts stealing calcium from the animal's bones to put calcium into the bloodstream. The bones actually self-destruct in order to provide the body with the calcium it needs.

The Body Craves Calcium

A turtle's body finds many uses for calcium. The hard, protective shell, of course, is made mostly of bone material. And in order to grow at the normal rate and in the proper shape, bones need calcium. Some less noticeable uses of calcium are for the proper functioning of muscles. Calcium is also required for the formation of eggs.

Many owners bring young turtles to Dr. Scott and complain that their pets have soft shells. In these cases, the shell is often contracted on the bottom, where it has been deformed by the pulling of muscles on the shell. In adult females, a calcium-related complaint is that the animal is egg bound - she can't expel her eggs. This may be because the adult's shell is deformed - too thick, thin, knobby, or bumpy - and won't allow the egg enough room to pass. Or a lack of calcium could prevent the uterus from contracting and pushing the egg out.

The Problem with Supplements

Dr. Scott pointed out again that calcium/phosphorus related problems are the most common ailments she sees. But simply feeding turtles a store-bought nutritional supplement isn't always the answer. Always read the back label of a supplement to check the calcium/phosphorus ratio. If the two minerals are perfectly balanced that's great if your turtle is `normal' - if it has no deficiencies. But since 90% of the animals Dr. Scott sees do have a calcium deficiency, adding equal amounts of calcium and phosphorus won't correct the imbalance. So read the label and choose a supplement with more calcium than phosphorus, or with calcium only and no phosphorus.

The Role of Vitamin D

Vitamin D is a very important nutrient in the diet because it enables the animal to absorb calcium from the digestive tract. Under the best conditions, a pet turtle will live outdoors where it will be exposed to sunlight, a chemical reaction goes on in the skin that provides Vitamin D to the animal's body. So most animals that live outdoors will probably be fine, and the owner will have no reason to supply Vitamin D as a supplement.

But animals that live indoors will need a Vitamin D supplement. Dr. Scott cautions us to remember that window glass and aquarium walls filter out the beneficial sun rays. A Reptisun [5 or] a special UVB light can provide Vitamin D producing rays. However, if the bulb is more than 8-10 inches above the animal, it does little good. Also, even if the light bulb has not burned out, after about six months, the bulbs loose their UVB producing effectiveness.***

Diseases Caused by Calcium Deficiency

Metabolic bone disease is the number one malady affecting captive reptiles. The term metabolic bone disease describes a whole series of symptoms caused by an imbalance of calcium, phosphorus or Vitamin D. In animals with the disease, calcium is pulled out of the bones to supply the body's demands. This leaves bones soft and weak, even rubbery. They break easily of become deformed, resulting in soft shells, bowed legs, or fallen jaws.

Foods with a normal calcium balance include asparagus, banana, tomato, cantaloupe, zucchini, strawberries, plum, carrot, figs, endive, alfalfa hay/pellets, earthworms, crickets ,slugs, and whole prey such as mice.

Problems with the Kidneys

Calcium can be lost through the kidneys. A sick animal can also loose the ability to convert Vitamin D through the kidneys.

Dietary Problems

Dr. Scott's basic message was to provide foods that have ratios of calcium to phosphorus that are higher than 2 to 1, and, stay away from things with more phosphorus than calcium. If you feed worms to your turtles, prefeed the worms with a low quality dog food (such as Walmart's Old Roy). Premium dog foods have too much Vitamin D and other minerals, and too little calcium. Instead of dog food, you can give the worms a commercial super prefeed, available at reptile-oriented pet stores.

Dr. Scott always likes to prevent problems before they develop. Hyper- or hypocalcemia and kidney problems can be detected by having blood work done on your pets. Every other year is frequent enough to detect problems before they become irreversible.

Miscellaneous Feeding Information

Commercial rabbit pellets are quite good for turtles. Made of alfalfa, the pellets are an excellent source of calcium, protein, and fiber. Fiber is quite important in proper functioning of the digestive tract; indeed, animals fed inadequate amounts of fiber will develop digestive problems. Dr. Scott pointed out that a turtle's digestive tract functions something like that of a horse - the turtle actually gains a lot of nutrition from the breakdown of fiber. Rabbit pellets can be moistened and then crumbled as a top dressing over other food.

Thiaminase is an enzyme that uses up a turtle's stores of Vitamin B. Vitamin B deficiency is indicated by various symptoms, including the animal's lifting its head way up over its back. Thiaminase is found in fish, and it increases in dead fish. It's OK to feed frozen fish now and then, but try to feed live or freshly killed fish whenever possible to avoid too much of this enzyme. The enzyme also occurs in the liver.

Herps need Vitamin C to boost their immune systems. A deficiency can cause susceptibility to many illnesses and parasites, and also bleeding into the joints. When fed a healthy diet, turtles can generate their own Vitamin C, so there is little need to supplement this nutrient. If supplementation is indicated, hoverer, crumbling part of a chewable Vitamin C tablet over the food should do the trick.

A lack of Vitamin K can cause bleeding problems and liver problems, such as hemorrhaging under the arms and blood spots under the tongue.

If your pets live outdoors any leftover food is likely to attract rats, raccoons, opossum and other vermin. these pests don't just like to eat turtle food, they like to eat turtles, and it's a slow and tortuous death. So be sure to clean up uneaten food, especially before nightfall. If you use poisons to control pests, be certain that your turtles can't reach it and eat it. Also, make sure the poison never comes in contact with any food item intended for your pets, and that water that may have come in contact with the poison can't run into the turtle pen.

Too much protein can correlate to kidney problems over time. Luckily, carnivorous turtles such as water turtles rarely develop these problems. But box turtles and especially tortoises should be safeguarded from eating too much protein.

Raw meat contains about 40 parts phosphorus to one part calcium - a very bad and potentially fatal ratio, especially for box turtles and tortoises.

Vitamin A is needed for maintenance of the mucus membranes. A lack of it can cause swelling of the eyes and blockage of the tear ducts. Liver is high in Vitamin A, and is a good supplement for animals with a deficiency in that vitamin. However, when overdosed, it becomes toxic. One sign of Vitamin A toxicity is that the animal's skin actually slips off. So, feed liver and other Vitamin A rich foods sparingly - no ore than once every two weeks. Better yet, feed foods rich in beta-carotene, which is converted to Vitamin A only as the body needs it. Foods high in Vitamin A include cod liver oil, yellow vegetables, carrots,and egg yolk.

Urine and waste buildup in an aquatic habitat can also cause swelling and watery eyes.

Assuming you provide a fiber-rich diet, constipation is usually not a problem of the digestive tract, but of what's in it, for instance a rock that gets swallowed along with some food. A little mineral oil may help the digestive tract to pass the foreign matter.

Sometimes as animal will strain too hard trying to pass feces. This can cause a prolapse of the rectal tissue - the insides actually get pushed outside. If this tissue gets dried out, it can become an emergency situation - get your pet to the vet immediately. In the meantime, keep the area clean and try to keep it moist with a little K-Y Jelly of saline solution. Some people have successfully treated this condition by sprinkling sugar on it - this absorbs moisture and reduces swelling enough that the tissue can be pulled back inside.

Most of us have seen our animals go off feed (become reluctant to eat) from time to time. This is especially prevalent during the hot summer months, or when turtles are occupied by something such as mating or egg laying. But if an animal remains off feed too long, it can develop fatty liver syndrome. This is a vicious circle type of malady, where the liver actually degenerates, causing the animal to become less interested in food, which causes further liver degeneration and on and on. As said, an occasional disinterest in food is normal, but if your animal doesn't eat for two weeks or more, or if it's losing weight or has changed behavior, you may want to try to tempt it to eat. Try raising the temperature (85 is about ideal for a reptile, a little more may stimulate more activity). Offer new interesting foods - wiggly live foods for box turtles and colorful vegetables for tortoises. Or try an old favorite. If the turtle still doesn't eat, have it checked by a vet.

Keeping your chelonians happy and healthy is easy, especially when they have a good place to live and a balanced diet.

***[At this time, it is not known if any of the UVB-type lights are adequate for turtles. There is another alternative to the fluorescent UBV and incandescent basking light pairing. There is a type of bulb called a UV-B Heat Lamp or Self-Ballasted Mercury Vapor light. Several companies are now marketing these and they produce higher levels of UVB than the reptile fluorescent lights. These bulbs continue to produce significant levels of UVB much longer than any fluorescent bulb.

NOTE: EXTREME CAUTION must be used with these bulbs. They also produce heat and also take the place of the basking bulb. UV-B Heat Lamps or Self-Ballasted Mercury Vapor lights at this time usually come in 100W and 160W so they must be used in a reflector socket that can withstand higher heat. These bulbs need to be placed higher than other bulbs due to their heat output. These bulbs are not for small tanks! They produce too much heat! Follow the manufacturer instructions exactly or you may endanger your turtle! Use a thermometer in the tank or container so you KNOW that you are not overheating the turtle.

If you would like to read about lighting for turtles/tortoises, see this link: UNDERSTANDING REPTILE LIGHTING SYSTEMS Please read the conclusion carefully.

In spite of UVB bulb improvements NO artificial light is an equal substitute for unfiltered sunlight. We do not condone housing any turtle or tortoise indoors on a permanent basis. Any native species living in a climate like their native climate should be housed outside permanently. Some non-native species or turtles that have been ill may need housing inside during cool/cold months.

Lights should be on approximately 12 hours each day on a regular cycle.]

Dr. Scott can be reached at Safari Animal Care Center, 2450 E. Main, League City, Texas, 281-332-5612.

Copyright (c) 2004 Gulf Coast Turtle and Tortoise Society
Permission is granted to copy for non-profit use with proper credit given. For any other use you must obtain permission.

Gulf Coast Turtle and Tortoise Society
1227 Whitestone Lane
Houston, TX 77073
Email us for quickest response: