Did You Know ?
Numerous aquatic snails are omnivorous, nothing prevents them from having a snack out of their equals in order to fight hunger; this behaviour can be observed with all ampullariidae (all species).
||This close-up on the rear shell part of Marisa cornuarietis perfectly illustrates a cannibalism that is specific to snails. Lack of calcary sometimes drives snails to help themselves where they can find some ... on other snails ! The damage thus caused is final.|
Some snails are carnivorous, they have even developped the only carachteristic that is required to fedd out of other snails: speed. Carnivorous gastropods generally dwell in salt water, they move fast and their shell has a rostrum placed on the shell end situated above the head.
Often considered as very slow, snails speed is nonetheless perfectly adapted to their feeding habit. algae eaters are slow, omnivorous ones are a little less slow moving and carnivorous ones ...
The first trace of planorbis goes back to the cretaceous (end of the secondary era, marked by the formation of chalk ...from -135 to -65 million years before mankind !), before mammals and birds. And the shell of planorbis variety that dwells in aquaria is identical to its ancestors !
Some snails are very usefull; some act as necrophagous and will eat the fishes that died and what body is stuck behind a decor element. But the fish may not be completely dead when snails decide to eat it. Melanoïdes tuberculata is an excellent exemple of "opportunist carnivorous snail". Anyhow, the snail remains very useful in this case as a fish that cannot defend itself within this framework is condemned anyhow.
The gasteropods operculum os composed of a flexible protein that is unique in its genera, this protein is called conchiolin. The operculum is attached to the upper part of the rear half of the snail foot.