Why Is My Turtle Biting Rocks?

Turtles can sometimes behave very strangely and it can be hard to understand them. They do all sorts of peculiar things – one of them being is a lot of them like to eat rocks.

Why is my turtle biting rocks? Usually because they have a calcium deficiency. They also can bite rocks out of boredom or due to mistaking them for food. 

In this post we’ll talk about the causes behind your turtle biting rocks, the health concerns it can cause, and how to make sure your turtle stays away from rocks for good. 

The Dangers of Biting Rocks 

Biting rocks is very dangerous for your turtle because if they swallow a piece of rock, this can lead to very serious health complications. Some turtles like to swallow small rocks whole or small pieces of gravel whole. This can lead to obstruction in your turtle which can only be solved by having surgery to remove the obstruction. 

Rocks, as we know, do not break down by stomach acids in the stomach since they are made of hard materials. Therefore, when your turtle consumes rocks they cannot be broken down and can have difficulty passing through the digestive tract. Sometimes they can get stuck together, especially if the turtle is eating more than one and they cluster up in the digestive system. 

This is called obstruction and is a serious health condition that could be life-threatening if you do not have the obstruction removed. Because of these very serious complications, it’s very important not to keep any gravel in their tank at all. Don’t even keep a little bit in your tank. 

If you think your turtle has eaten a piece of gravel or small rock, make sure to keep an eye on them for a few days. If their behavior changes at all, take them to a vet immediately. 

While one or two stones probably will not cause problems, if your turtle has access to rocks it is possible for them to eat several and because of that, this increases the chance of causing an obstruction. 

Symptoms of Obstruction

If you have noticed that your turtle enjoys biting on rocks and have even seen them eat one, keep an eye on their behavior to make sure they’re not exhibiting any signs of internal digestive obstruction. 

Things to be on the lookout for are: 

  • Lethargy
  • Depression 
  • Constipation 
  • Loss of Appetite 

All of these symptoms are big indicators that your turtle is suffering from obstruction and should be taken to a vet for an examination, Xray, and possible surgery. 

So, this is everything you’re supposed to do if your turtle bites or eats rocks. But why do they do this in the first place? Mostly because of a calcium deficiency. But there are other reasons, too. Let’s explore these reasons in more depth. 

Calcium Deficiency

Why does your turtle compulsively find rocks to bite at or swallow? This question has puzzled turtle and tortoise owners alike for years. The reason is because rocks contain a lot of minerals. They contain tons of calcium, iron, phosphorus, vitamin D3, and other essential nutrients needed for turtles’ health and well-being. 

Turtles crave all of these minerals. So much so that when they aren’t getting enough of these essential minerals they will go out and try to find another source. That source is oftentimes small rocks in the bottom of your tank. 

If you see your turtle biting at a rock or eating gravel there’s a good chance you aren’t feeding them enough calcium in their diet. 

The good news though is that this behavior is a great way to tell if a turtle is getting enough nutrients or not. Even better news: there are lots of foods and supplements you can feed to your turtle if you are sensing they’re not getting enough calcium or iron. 

Leafy greens, for example, are rich in calcium. You can also try feeding them more aquatic plants, collards, turnip greens, red and green leaf lettuce, and romaine lettuce if you think their calcium level is down.

It is important to note that you should avoid feeding them spinach. Even though spinach does contain high calcium it also contains oxalate which prevents calcium from being absorbed in the body. 

If you are still suspecting your turtle is suffering from a lack of calcium, there are supplements you can buy for them. A cuttlebone is a great way to ensure your turtle is getting a boost of calcium. There are also plenty of calcium powders you can use as supplements as well. 

Also remember that turtles can only process these nutrients with an adequate amount of UVB ray light. Make sure that their UVB light is working and they are getting the right amount of UVB light to aid digestion. 

If you have checked to make sure they are getting an adequate amount of calcium in their diet and they are still drawn to rocks it may be time to consider other reasons why your turtle is displaying this behavior. 


There are plenty of other reasons why your turtle may have the urge to eat rocks.  Sometimes when turtles are in enclosures they can get bored when they don’t have enough stimulation to keep them occupied. They may swim down to the bottom of the tank to eat rocks just so there’s something for them to do. 

Luckily there are a few things to do to enrich their lives if you think your turtle is suffering from cabin fever. First thing you must do is make sure their tank enclosure is big enough for their body so they have enough water to swim in. 

The rule of thumb is usually 10 gallons of water per inch of the turtle. You must have a minimum of 20 gallons for baby turtles. A lot of turtles, like the popular red-eared slider, can typically grow up to 12 inches so be prepared to own a fairly large tank. 

You can also occupy them with other ways, too. Hiding their food will keep them active both physically and mentally and also give them a sense of earning once they have found their food. This is a great thing to do if you think your turtle is suffering from severe boredom. 

More handling time could also help ease the feeling of boredom. It could be that your turtle is simply stir crazy and handling them more often may be a way to fix that.

If you are able to, you can also buy more turtles so that they have more stimulation and friends to play with. However, this can get expensive and also lead to a lot of work. So if this isn’t the best option, you may want to try other alternatives first. 

Mistaking for Food

Your turtle can also mistake pebbles for food. Although turtles have pretty good eyesight, those little pebbles can oftentimes look like pellets of food – especially when the pebbles are smaller than their heads or mouths.

Tank Care 

Besides the calcium deficiency, sometimes you simply cannot control your turtle enough to get them to not eat rocks. Therefore, it is never recommended to keep rocks at the bottom of your tank. Little rocks especially must be removed but even larger rocks can cause issues as your turtle can bite into it and break off a piece of rock to swallow.  To be on the safe side, we recommend you never put anything inedible in your tank that your turtle may be able to swallow. 


Turtles eat or bite rocks for multiple reasons. Sometimes they crave the calcium or other nutrients found in rocks. In this case, check your turtle’s diet to make sure they are getting an adequate amount of calcium. It is also smart to double check their UVB light as this is how they absorb calcium into their body. 

They may also want to digest rocks because of boredom or due to mistaking it for food. While you can do something about their boredom by doing small things to enrich their lives, it’s just smart to remove the temptation all together and never have any rock (big or small) available in their tank. 

Swallowing rocks can cause serious, life-threatening health problems for your turtle. Because rocks cannot be broken down in their digestive system, if they digest rocks (especially when they digest multiple rocks) these rocks can get stuck and cause blockages in the intestinal system, which is referred to as an obstruction.

Therefore, it is important to keep an eye on your turtle and when you suspect they have an obstruction to bring them to a vet immediately. 




I’m Devin Nunn, an average joe that just so happens to have a deep love and passion for everything to do with reptiles. Because taking care of them for the vast majority of my life wasn’t fulfilling enough, I decided to begin educating others about them through my articles. read more...