Cuttlefish bones are among the best calcium supplements.
Tortoises given cuttlefish are less likely to get developmental shell conditions, such as soft shell, pyramiding, and shell rot. Also, cuttlefish give tortoises something abrasive to grind down their beaks.
Without enough calcium in their diet, tortoises are at risk of developing illnesses, such as metabolic bone disease. Tortoises need sufficient vitamin D3 from UVB light for them to absorb calcium.
What is a Cuttlefish Bone?
Cuttlefish bones are the internal shells of cuttlefish, which are marine mollusks.
Their unique bone structure helps with buoyancy control. When a cuttlefish dies, its flesh dissolves, but the bones remain, so cuttlebones can be found all over the ocean.
Cuttlefish bones are oblong, have a chalky texture, and are white. They’re made of 85% calcium carbonate, while the rest are minerals like phosphorus, sodium magnesium, and iron.
Cuttlefish bones can be found in the ocean, but you can get them at most pet stores. They’re a popular source of calcium for many avian and reptilian pets. Before being given to an animal, they must be sanitized to kill any harmful germs and bacteria.
This is especially important for tortoises. As land reptiles, their bodies aren’t accustomed to interacting with the various microorganisms found in the ocean.
Why Do Tortoises Need Cuttlefish Bones?
Tortoises need calcium in their diet because much of their physiology depends on it, including their:
Tortoises have an intricate skeletal structure, so they need calcium to grow strong, healthy bones.
According to Veterinary Record, tortoises with a consistent amount of calcium and vitamin D3 in their diets grow much more than those that don’t.
Without enough calcium, tortoises won’t grow properly and will have a weaker immune system.
What is Metabolic Bone Disease?
Metabolic bone disease is an umbrella term used to describe any disease that affects a tortoise’s bones and shell. According to Zoo and Wildlife Medicine, metabolic bone disease is the most common medical disorder in captive tortoises.
It includes conditions like Paget’s disease, osteoporosis, or osteomalacia. Tortoises that are most at-risk to develop metabolic bone disease are hatchlings and egg-laying females.
Hatchlings grow most during the first few years of their lives so, if there isn’t enough calcium and vitamin D3 in their diet, it’ll impact their growth and development. Egg shells are partially made of keratin and calcium, so an egg-laying female tortoise needs of calcium in her diet to lay healthy eggs.
Because metabolic bone disease is so common, you’ll need to recognize the signs. Loss of appetite, lethargy, constipation, a deformed shell, and bowed legs are all signs that your tortoise needs calcium.
The top of tortoise shells (carapace) and the bottom (plastron) are made of keratin, which is the same protein that human hair and nails are made of.
The amount of calcium in a tortoise’s diet affects how thick the keratin is. So, if the tortoise has a calcium deficiency, its shell won’t grow along with it.
A lack of calcium can cause the shell to soften up. Because tortoises use their shells for protection, having a soft shell puts it at risk of injury.
Pyramiding, which is excessive upwards growth of shell scutes, can be caused by calcium deficiency. While the condition can’t be reversed, it can be prevented by the right dietary regimen.
Female tortoises lay eggs made of keratin and calcium, so it’s important to give a nesting tortoise enough calcium so that she can lay healthy eggs without compromising her own health.
Without it, the egg shells will break too easily, or egg binding can occur, which can be life-threatening.
Other Cuttlefish Bone Benefits
Tortoises will grind down their beaks when they dig burrows and look for food. Captive tortoises aren’t always as active as wild tortoises, so there aren’t as many opportunities to keep their beaks short.
Beak overgrowth is a severe problem for captive tortoises, affecting their ability to eat and perform certain tasks. To ensure they’re able to grind their beaks down themselves, give them a cuttlefish bone.
Also, cuttlefish bones can be used to entertain tortoises. Tortoises like rummaging through the items they have in their enclosures, and a cuttlefish bone is an entertaining item your tortoise can interact with.
Can Tortoises Have Too Much Calcium?
Tortoises can have too much calcium, so cuttlefish should only be used as a dietary supplement. Too much calcium can cause deformed shells. However, this is unlikely to be a problem.
While it’s true that many tortoises can self-regulate their calcium intake, some can’t. Some tortoise species, like sulcata tortoises, come from areas where resources are limited. When encountering anything with nutritious value, they gorge on it because their survival instincts tell them to.
Your tortoise only needs some calcium 3-4 times a week.
How To Feed Cuttlebone to Tortoise
There are several ways you can feed cuttlebone to tortoises.
You can do the following:
- Place the entire cuttlefish bone in the enclosure and let the tortoise eat on its own
- Crush it and sprinkle it on top of the tortoise’s food
- Hand feed it a portion
If you drop the cuttlefish bone in the enclosure, you’ll not only give them a source of calcium, but you’ll provide a way to trim its beak.
The downside to this is that the tortoise could ingest too much calcium. Also, cuttlebone attracts moisture, so you need to check on it in case it gets moldy.
Handfeeding a portion of cuttlebone prevents excessive calcium intake. There may be some tortoises that aren’t all that fond of cuttlebone, so crushing and sprinkling it on food is an option.
Alternatives to Cuttlebone
Here are some other sources of calcium:
- Calcium powder
- Mineral blocks
- Crushed eggshells (not raw)
- Crushed oyster shells
- Plaster blocks
- Boiled chicken bones
- Manu blocks
These alternatives contain a healthy amount of calcium and are safe for tortoises.
Be wary of cuttlebone alternatives that come in a special shape, color, or flavor, as these are often chemically altered or made with a binding agent that’s unnatural.
Consuming some cuttlebone a few times per week is a good way to top up a tortoise’s calcium levels. However, in order for the body to absorb the calcium, it’ll need vitamin D3 via UVB lighting.