Cuttlebone is a great calcium supplement for turtles and tortoises. It provides a great deal of enrichment for them. Not only nutritionally, but also as something to interact with. Especially for aquatic turtles.
What is Cuttlebone?
Interestingly, cuttlebone is an actual bone from the Cuttlefish- Sepia officinalis. They are closely related to octopus. They produce a brown ink which the color sepia is named after. (PBS)
photo: Richard James on Flickr
Cuttlefish also have a remarkable camouflaging mechanism. Checkout this video by BBC:
Cuttlebone certainly comes from a remarkable creature! All we really need to know is that it's loaded with calcium for our turtles to chomp down on.
Where to Get Cuttlebone
You will often find cuttlebone sold for birds in chain pet stores and large department stores. I've never tried giving my turtles cuttlebone for birds, but it should not make much difference if it is easy for you to pick up this way. One thing to note however is to be sure to remove the metal piece that is usually included to attach the bone to a birdcage.
You can also find cuttlebone at times in specialty pet stores. You'll want to inspect them to make sure they are not overly discolored or have a strong odor.
This can be a great deal if they are offered in bulk and they are good quality. If you do not have extra-large turtles, I would recommend avoiding large cuttlebones. It is more likely for part of it to be wasted, if floating a whole piece instead of breaking the cuttlebone into pieces.
If you don't have a local pet store that offers cuttlebone in bulk for a good price, I would recommend picking up the cuttlebone product made by Zoo Med: Turtle Bone. They come in 2 packs and can often be found at pet stores.
Or, you can easily pick them up online.
Find them on Chewy.com here. (affiliate link)
Stock up on Amazon here.
How to Offer Cuttlebone to Your Turtles
A cuttlebone can be placed in a water setup or in a land setup. It can be offered to any turtle or tortoise as well. You can experiment with leaving it whole or breaking it into pieces (which may be ideal for adding to land setups).
In aquatic setups, I've found that floating a whole bone in the water allows my turtle to snack on it for weeks before it starts to discolor or is completely eaten.
If your turtle simply does not seem to have the taste for it after several weeks of providing access to it, consider offering it again after a month or two. Keep offering it periodically even if they still haven't taken interest so far. You never know if your turtle's taste or needs will change.
The hard "backing" layer found on one side of all cuttlebones should be taken off for safety reasons as well as to make it more appealing to your turtle.
This backing is harder than the rest of the bone, and may or may not be an issue for your turtle. A common myth is that the backing is actually plastic; this is not true. It is a natural part of the bone, however it can be hard and sharp compared to the rest of it.
Given this, the safest way to offer cuttlebone is to remove this backing carefully with a knife. It is a thin layer, and should come off without much trouble. If you accidentally break the whole piece into chunks when removing backing, this is fine. Whether you give it to your turtle(s) in pieces or in one large piece is a matter of preference.
Once the backing is removed, it is safe for any turtle or tortoise. Therefore, it could be given to any age of turtle as well. Hatchlings may not be able to bite strong enough to eat it, and young turtles may be less interested than adult turtles. For these reasons, you might want to wait to offer cuttlebone until your turtle is 10 or more months old. But again, it won't hurt at any age.
Be sure to throw out your cuttlebone when it becomes significantly discolored or dirty.
Take Home Points
Cuttlebone pros and cons:
Pros: Great calcium supplement, inexpensive, provides enrichment
Cons: Not all turtles take advantage of it when offered, some may have to be thrown out when dirty or discolored
Recommended for: Most turtles and tortoises
Not recommended for: Hatchling turtles and turtles too small to bite down on the cuttlebone
PBS animal guide (found here)
Visit Richard James on Flickr (here)
How old or big should a turtle be when offered a cuttlebone