Have you ever noticed your pet tortoise eating dirt, soil, or even bits of stone and rocks, either while inside a terrarium or outdoors? If so, you may wonder if this is normal tortoise behavior, or if it warrants a call to your veterinarian.
Why is my tortoise eating dirt? Your tortoise is eating dirt because he is not receiving the appropriate amount of vitamins and minerals, such as calcium, in his diet. When tortoises are deficient in minerals such as calcium, they will deliberately seek calcium-rich items in their environment to make up for it.
Now that you know why your tortoise has been snacking on mud pies and dirt cakes, let’s get into how you can make him stop. There are plenty of things you can do for your tortoise, such as improving his diet, to ensure he doesn’t feel the need to seek out necessary minerals via dirt or substrate.
Improper Diet and Associated Problems
In the wild, tortoises obtain their calcium in a few different ways. First, they consume a steady diet of calcium-rich vegetation. During mealtime, they also ingest small amounts of mineral-rich sand and soil. Lastly, they will find and consume other calcium-rich items in their environment, such as bones and snail shells.
Your captive tortoise will almost never receive the requisite amount of calcium via his diet alone. Additionally, he does not have the same opportunity to forage for other calcium-rich items like he would in the wild… so he might just eat the dirt or substrate in his enclosure in a desperate attempt to mimic this behavior.
The typical diet of a pet tortoise is made up almost entirely of vegetables and fruit, which don’t usually contain the amount of calcium a tortoise really needs. To compound this issue, captive tortoises also have a greater risk of receiving insufficient exposure to sunlight (or artificial UVB light), and therefore don’t produce adequate amounts of vitamin D3.
Many captive tortoises also consume higher amounts of phosphorus and other substances (such as oxalates) that inhibit calcium absorption.
Tortoises desperately need substantial amounts of calcium for good bone and shell growth. Pet reptiles who are deficient in calcium are at great risk for developing Metabolic Bone Disease (MBD).
MBD is caused by an imbalance of calcium and phosphorus in the body and is the most common nutritional problem found in reptiles. This disorder can cause soft, weak, brittle bones, and irregular shell growth in turtles and tortoises.
One of the most common and visible signs of Metabolic Bone Disease in tortoises is “pyramiding” of their shell. A healthy tortoise has an even, smooth, domed shell. If one or several of the segments, or scutes, on a tortoise’s shell grows abnormally high, this is referred to as “pyramiding”.
Excessive pyramiding can cause a tortoise’s shell to become deformed, can negatively affect their spine, and will cause issues with mobility.
Other signs of Metabolic Bone Disease include abnormal beak growth, a humped back, an unsteady, limping gait, bowed legs, a rubbery or soft shell, constipation, lethargy, and lack of appetite.
If you notice any of these symptoms in your pet tortoise, contact your veterinarian immediately. If these symptoms are present it means that Metabolic Bone Disease has progressed significantly.
This condition will need to be diagnosed (with x-rays and blood work) and treated immediately. Your veterinarian can also talk with you about how you can improve your tortoise’s habitat and diet and improve his overall health.
Proper Tortoise Diet
A proper diet is absolutely crucial to the health of your tortoise. Most tortoises are herbivores, or vegetarians, by nature. Red-footed and yellow-footed tortoises, for example, can also be omnivores (they’ve been known to eat carrion, as well as slugs, snails, and other slow-moving invertebrates in the wild1).
Most tortoises should be fed every day, especially when they’re young. A tortoise’s captive diet should consist mostly of dark, leafy green vegetables such as kale, dandelion greens (which are high in calcium!), turnip greens, romaine lettuce, endive, Swiss chard, and mustard greens.
You should avoid giving your tortoise large amounts of greens that are high in oxalates, such as spinach, collard greens, beet greens, and parsley, but a little bit is fine.
You can also supplement these nutrient-rich greens with other vegetables, such as carrots, squash, green beans, and sweet potatoes. Give fruit to your tortoise sparingly, as more of an occasional treat. Acceptable fruits include melon, strawberries, pumpkin, pineapple, papaya, figs, mango, and kiwifruit.
There are also several plants and flowers that tortoises can safely enjoy, and some of them can be found right in your own garden. These include squash flowers, Geraniums, Tropical Hibiscus, Aloe, Petunia, Oregano, rose petals, Garden sage, dandelion, and certain types of clover.
There are also certain vegetables and plants that are downright dangerous for tortoises (including Avocado, apple seeds, and Oak). Be sure to do thorough research before you offer any type of plant to your tortoise.
In addition to a varied diet of nutritious vegetables, your pet tortoise will need proper supplementation of calcium, magnesium, and vitamin A. Most veterinarians recommend dusting your adult tortoise’s food with an appropriate calcium powder two to three times per week.
Some turtle owners prefer to provide their pet tortoises with “turtle blocks” or blocks of calcium carbonate that they can gnaw on to obtain the proper minerals. You should also speak to your veterinarian if you are considering this option.
You may also want to consider providing your tortoise with a multivitamin that has been specifically formulated for reptiles. Your veterinarian can provide you with more information about these types of vitamins, as well as the proper frequency of supplementation for tortoises of all ages.
You should also be sure to provide your tortoise with fresh drinking water every day.
A Healthy Habitat
Besides feeding your tortoise a well-balanced diet, you’ll need to house them in an environment that allows their bodies to properly digest and absorb the vitamins and minerals they need for good health.
Turtles need regular exposure to UVB light, either in the form of indirect sunlight, or a special UVB reptile bulb. Tortoises need this type of light to synthesize vitamin D (which aids in healthy calcium absorption) and for healthy digestion in general. They need at least 12 hours of UVB light per day for good health.
You also need to be sure to keep your turtle’s home at the proper temperature. Different species of tortoises have different temperature requirements. Be sure to do some thorough research on the average high and low temperatures in your tortoise’s natural habitat. You can then use these numbers as targets for the temperatures in his captive habitat. Below are a few examples to get you started.
European tortoises, such as a Horsfield, enjoy more temperate climates. The basking, or warm end of their enclosure should be around 95-100℉, and the cool side should be between 70-75℉. Mediterranean species of tortoise, such as the Greek tortoise, like it a little warmer. The warm side of their enclosure should be about 95-105℉ and the cool side should range from 75-85℉.
The same type of rules go for the humidity level in your tortoise’s enclosure. Be sure to do your research on this and provide a substrate that will help maintain the humidity level that is appropriate for your individual tortoise. Habitats that are damper than they should be can contribute to issues such as shell rot and respiratory infections.
Speaking of substrate, you’ll want to make sure you’re providing the right type for your tortoise, not only to maintain proper humidity levels, but also to keep him safe if he does ingest it. Consumption of the wrong type of substrate can cause your tortoise all sorts of issues, such as constipation and impaction.
One type of inexpensive, natural substrate that you pretty much cannot go wrong with is soil. However, it has its cons as well (too dusty if it’s dry, and muddy when wet). Again, just be sure to do your homework.
If you notice your tortoise eating dirt or substrate, don’t become too alarmed. While this is natural behavior, it does warrant a bit of concern on your part. Be sure that you are providing your tortoise with a varied, nutritious diet of leafy greens, supplementing his diet properly, and are providing a healthy environment in which he can thrive.
Always be sure to speak to your veterinarian if you have additional concerns, or if you think your turtle has ingested any item that may cause impaction or other health problems.