Should I Give my Tortoise Calcium?

As far as any animal is concerned, having the right amount of minerals and nutrients is very important. The lack of any, or even too much of it, can be detrimental to their health, especially so if they are still young and developing. Any animal that doesn’t get the right amount of nutrients as they grow will end up becoming stunted and they can also develop severe health problems that will haunt them their entire lives. This is especially true when it comes to tortoises and their need for calcium.

Why should you give tortoises calcium? Calcium is vital for developing a stronger shell and bones and also important for other bodily functions, such as proper muscle development. The lack of calcium in a tortoise can lead to mobility problems, not only because of underdeveloped bones, but also their inability to control their muscles. Tortoise calcium is also important for the development of eggs and even during the egg laying process itself.

The lack of calcium can also lead to diseases and deformities that if not corrected early, can lead to your tortoise dying a slow, agonizing death. Today, let’s look into this often taken for granted mineral, why it’s so important and how you can give your tortoise more of it. If you want to know more about other health conditions your tortoise may face check out in depth article on common tortoise health problems.

Tortoise common health problems

Why Tortoise Calcium is Important

Tortoises are very unique animals. They have both an endoskeleton, which compose of the bones inside their bodies, and an exoskeleton, which is their shell. Not many animals share this body setup. In order to maintain the structural integrity of both skeletal systems, it’s important to have a lot of calcium.

Importance of Calcium for Mobility

Calcium makes up a lot of a tortoise’s bones and shell, and the lack of it can cause them to become porous and structurally weak. If bones don’t have structural strength, tortoises won’t be able to support their entire weight, and as you may already know, tortoises can be very heavy. On top of that, if a tortoise is unable to absorb enough calcium as they grow up, their shells can also become deformed. Check out our full article on why your tortoise’s shell may be soft.

Why your tortoise’s shell may be soft

Although shells may look like stiff plates of bone, they are vital to a tortoise’s mobility. Why? Because a tortoise’s spine is fused to the inside portions of their shell. A deformed shell means a deformed spine, which means a tortoise won’t be able to support their own weight. Imagine being forced to walk with a bad posture that you can never correct. On top of that, the space inside their shells where the organs are will also be compromised due to these disfigurements.

Aside from the bones themselves, calcium is also vital for muscle contraction and overall locomotion. The lack of tortoise calcium can lead to muscles that are weak overall, leading to the same mobility problems as weaker bone structures do. Basically, the lack of calcium will lead to a very lethargic tortoise.

Tortoise Calcium and Egg Laying

The importance of tortoise calcium is not limited to just a healthy anatomy and physiology. Calcium is also vital for the creation of new life. Tortoise eggs, specifically their shells, require calcium to develop. A pregnant female who doesn’t get enough calcium will develop eggs that have soft, leathery shells, as opposed to strong, porcelain-like shells.

When these deformed eggs are buried underground, they won’t be able to support their own weight, let alone the weight of the other eggs that it is laid with, or the soil placed on top of it. The trouble isn’t limited to the underdeveloped eggs, either. The female laying the clutch will also be in danger. Remember when we mentioned how calcium is vital to muscle contractions?

If you’re familiar how a lot of animals, including humans, give birth, then you should know how important muscle contractions are. Female tortoises will need a lot of calcium to help them expel the eggs inside their bodies. Lack of calcium means the inability to expel these eggs, which may result in your tortoise dying if left unchecked.

Conditions Associated with Calcium Deficiency

At this point, you should already have an idea how vital tortoise calcium is. The lack of it will lead to a whole host of developmental problems amongst tortoises. Here are just a few of them.

Metabolic Bone Disease

Metabolic bone disease, or MBD, is a very common husbandry problem that haunts many tortoise keepers. MBD can be the result of the lack of UV light or phosphorous imbalance, but the main issue with it is a severe lack in calcium, whether due to mineral imbalance or the tortoise itself being unable to absorb calcium. This deficiency usually leads to the tortoise absorbing the stored calcium in the bones and the shell to help maintain the metabolic functions of its body.

This calcium deficiency can lead to brittle bones, a deformed skeletal structure, and a rubbery shell. Not only will this hamper your tortoise’s ability to move freely, it is also very uncomfortable for them. Metabolic bone disease can still be corrected if the tortoise is young enough, but once they’ve reached adulthood, the damage tends to be permanent. Treating advanced MBD involves injecting calcium and vitamin D3 directly into the tortoise’s bloodstream. If you want more information on Metabolic Bone Disease in tortoise’s we have covered this topic in detail in these two articles.

Treating metabolic bone disease in tortoise

Signs of metabolic bone disease in tortoise


If metabolic bone disease affects the tortoise’s bones, then hypocalcemia affects the rest of their body. Not many people know that calcium isn’t just for creating strong bones, it’s also used by the body to maintain certain metabolic functions. These functions include neurological activities, muscle contraction, and even some level of hormonal control.

Low tortoise calcium levels in their blood will result in pretty much a partial shutdown of the body. In most cases, hypocalcemia can be seen as uncontrollable muscle spasms, and at worse, seizures. Not only does this make it difficult for your tortoise to move, it will pretty much render them unable to function overall.

Egg Binding

Tortoise keepers who breed tortoises will also need to be wary of their tortoise’s calcium levels, especially for their egg laying females. Hypocalcemia can severely affect a tortoise’s ability to lay their eggs, simply by taking away their ability to contract their muscles. If this happens, then it’s very likely that a female tortoise will end up with a condition known as dystocia, otherwise known as egg binding or egg retention.

When tortoises aren’t able to lay their eggs, these eggs will continue taking up space within a tortoise’s body, putting pressure on the rest of their organs. This condition will usually end up fatal to the reptile. Treatment for egg bound tortoises include administering oxytocin to help induce labor. If that doesn’t work, surgery is usually the next step.

Lethargy and Appetite Loss

Because calcium deficiency usually involves the weakening of the muscles and the skeletal structure, tortoises who don’t get enough calcium rarely move a lot. In severe cases of calcium deficiency, even the smallest of movements can cause discomfort or even pain for the tortoise. This condition is also usually accompanied by a sudden loss of appetite. This combination makes it very difficult to treat hypocalcemia through adjusting the diet, so veterinary treatments that include force feeding or injecting calcium may be required.

Good Sources of Calcium

Now that you have an understanding of the importance of calcium, you’re probably looking for ways to improve you’re the tortoise calcium levels on your pet. This can be done in many ways, but mostly it involves changing up your tortoise’s overall diet. Here are some of the best sources of calcium for your tortoise.

Green Leafy Vegetables

The best sources for dietary calcium are usually the easiest to find. Green leafy vegetables you find in the supermarket are rich not only in calcium, but also in other nutrients. Feeding your tortoise any of these vegetables will not only prevent calcium deficiency, it will also round out their entire nutrition. Good vegetables for you to consider include collard greens, kale, romaine lettuce, and jute.

Calcium Supplements

If your tortoise is a picky eater, then it might be a bit tricky trying to feed them a varied diet. As such, calcium can be hard to come by. A good way around this is to sprinkle their favorite food with calcium powder or other supplements. Any calcium supplement like Zoo Med’s Repti Calcium will be great for this. In fact I use this product with my own tortoise.

Tortoise / Turtle Blocks

Another good way to help encourage your tortoise to consume more calcium is by using turtle or tortoise blocks. You may notice your tortoise biting into hard objects from time to time. This is their way of trimming their beaks naturally. Tortoise blocks are blocks of calcium and other minerals that your tortoise can bite into, not only helping with shaving down their beaks, but can also provide them a decent source of calcium. A good brand to look into is Zoo Med’s Banquet Block, which contains vegetable extracts on top of the calcium.

Final Thoughts

Trace minerals and nutrients act as building blocks to a healthy tortoise. Take one out, and the whole thing collapses. Some of these minerals, like calcium, may seem trivial, and your tortoise might seem fine initially when deprived of them, but these things do have consequences. Removing them completely can prove fatal in the long run, especially so if your tortoise is still growing.

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