natural habitat/diet

[KathyM]

OK so this is where I put my neck on the line - either people are going to be like me and not know this, or they're going to think I'm a bit fick.

Baz and I were alking about the margie tank and how we want to set it up as close to their natural habitat as possible, and this question popped out that neither of us could answer:

How do snails get calcium in the wild?

*runs and hides*

[gabi]

I think from their food and from eating other snailies shells....my Lignus babies seem to take their whole calcium out of the food, cause they are never even near the cuttlefish or calcium powder I have for them in the little tank.

[Paul]

That's right, from food. Calcium carbonate like oyster and cuttlefish is only 40% calcium, the rest is carbon and oxygen so although it is a great source of calcium the quantity can be misleading. They probably get some from animal bones as well as old shells.

Wild snails' shells are often a hell of a lot thinner than their captive counterparts. I read somewhere that Helix apsersa for example, can attain shell weights 4 times heavier than wild ones.

[incantrix]

Don't they get some calcium from rasping minerals from rocks too? I think Limestone is rich in Calcium Carbonate, I'm sure I read somewhere that they get some from that. Don't quote me though, I was useless at science at school!

[Paul]

That's correct, they utilise limestone definitely.

[KathyM]

So in conclusion, I'm a bit fick *lol*. Thanks for the info, it's very interesting

[knownstranger]

if u have cuttle it helps there shell grow back, my snails like there sprayed food, (water sprayer)

[Robert Nordsieck]

Hi there,

there are several ways to get calcium carbonate (CaCO₃) for a snail:

First: From the food: There are even special cells in the main digestive gland that gain it from the food. (Which is one of the reasons not to refer to this gland as "liver").

Second: The foot sole. I don't exactly know, if all snails can do it, but at least Helix pomatia can, when deprived of CaCO₃, the can release carbon dioxide into their slime. The water in the slime is changed into carbonic acid and so CaCO₃ can be directly dissolved from a limestone surface. The snail will sit there for a time and after it left there is a mark to be seen.

A small additional information: There is a Mediterranean carnivorous snail, Poiretia cornea, that has changed that ability into dissolving other snails' shell walls to eat them

Regards
Robert

[Paul]

Achatininae can obtain calcium though their foot by dissolving calcium carbonate. Some seem to prefer this method to eating it. and many are observed in Africa using empty snail shells.

In the Dai Herbert & Dick Kilburn book it says...

"We have watched a young brown-lipped agate snails (Metachatina Kraussi) in captivity climb onto the shell of a larger individual of the pink-lipped agate snail (Achatina immaculata) and, flattening its foot over a large area of the latter's shell, it slowly etched away so much of the shell material that, over a period of days, a large hole was formed. After separation of the two, the victim was allowed to snack ad libitum on a supply of chalk, and within a week had repaired the hole."

It is a useful method and allows them to extract calcium from otherwise inedible sources. When clean cuttlefish goesi n the tank, they eat it but in a matter of days I find them sitting on it instead. My immaculata actually grip smaller pieces and hide with them.