# What is the backing on cuttlebones made of, anyway?



## GeoTerraTestudo (Jul 29, 2012)

I have always given my tortoises artificial cuttlebones from the petstore, which are marketed toward birds. I have always left the backing on, as I thought it was a more dense form of calcium, and have never had a problem. However, now some folks are saying it's made of plastic? Is that true? If so, that can't be good for tortoises if they swallow it. Does anyone know what it's actually made of? If it's not natural, then I will have to switch to real cuttlebones, because the sound of scraping calcium away from the backing would drive me bonkers.


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## Edna (Jul 29, 2012)

Cuttlebone is a natural product of cuttlefish. I don't cut off the hard part.

http://en.wikipedia.org/wiki/Cuttlebone


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## GeoTerraTestudo (Jul 29, 2012)

Edna said:


> Cuttlebone is a natural product of cuttlefish. I don't cut off the hard part.
> 
> http://en.wikipedia.org/wiki/Cuttlebone



Well, that's the thing. There's natural cuttlebone, which is made mostly of calcium carbonate and comes from cuttlefish (a mollusk):

http://www.carolinapetsupply.com/catalog/index.php?main_page=product_info&cPath=29&products_id=66

And then there's artificial cuttlebone, which is made mostly of calcium sulfate, and is molded in the shape of real cuttlebone and attached to some sort of backing:

http://www.petco.com/product/6382/Petco-Cuttlebone-with-Metal-Holder.aspx?CoreCat=OnSiteSearch

I realize natural cuttlebone is fine, but what about the backing? I always thought it was safe for tortoises to eat, because as long as it's made of calcium, then even if it has fairly sharp edges, tortoises can handle sharp foods (like snail shell shards or spiny plants). But if it's not even made of calcium, then I guess it really would be important to either remove it, or else switch to another product. So what exactly is the backing made of?


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## Edna (Jul 29, 2012)

Where does it say that Petco cuttlebone is artificial?

When I searched 'artificial cuttlebone' what I found was mineral blocks.


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## CLMoss (Jul 29, 2012)

I believe that both, petco and carolina pet supply is the same product. And like Geo, I thought that the backing was natural...


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## GeoTerraTestudo (Jul 29, 2012)

Edna said:


> Where does it say that Petco cuttlebone is artificial?
> 
> When I searched 'artificial cuttlebone' what I found was mineral blocks.



It doesn't say so, but I know some cuttlebones are natural, others artificial. Natural cuttlebones have no backing (it's just a structure within the cuttlefish). They also vary in shape from elliptical to elongate, and are more dense with a smooth surface, but with ridges.

In contrast, the cuttlebones I get at the pet store have a backing, are all the same shape, not very dense, and have a rougher surface with few ridges. It does not say whether they are natural or artificial, but these characteristics indicate to me that the kind I have now are man-made, while others may be harvested from the sea.



CLMoss said:


> I believe that both, petco and carolina pet supply is the same product. And like Geo, I thought that the backing was natural...



It's probably harder to find real cuttlebone nowadays, since that would deplete wild populations of cuttlefish. Probably more sustainably to make mineral blocks, and if in the shape of cuttlebone, then so be it. But yeah, I always thought the backing was safe, so now I want to make sure.


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## clare n (Jul 29, 2012)

This is strange, I was having this conversation with my husband today about taking the plastic off. He looked at me as if I was mad, telling me that was the outer part of the bone, the top part that just has a different density, not plastic at all. I read the plastic part on here somewhere.


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## Edna (Jul 29, 2012)

I give up. The cuttlebones from Petco are natural cuttlebones. They may be processed to all look alike, cleaned, whatever. They may not be from "old growth cuttlefish". Natural cuttlebones just the same.


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## GeoTerraTestudo (Jul 29, 2012)

Edna said:


> I give up. The cuttlebones from Petco are natural cuttlebones. They may be processed to all look alike, cleaned, whatever. They may not be from "old growth cuttlefish". Natural cuttlebones just the same.



Well, you may be right. In that case, the "backing" is not backing at all, but just more compact calcium carbonate:







Cuttlebone, which is really just the internal shell of a mollusk, is very similar to snail shell, which an external mollusk shell. Turtles eat snails all the time, so every part of the cuttlebone should be fine, too.

Cuttlebone of _Sepia officinalis_:






Tortoise (probably _Testudo graeca ibera_) gnawing on soft side of cuttlebone:


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