Most people know a snail when they see one, but it is less common to be able to tell the difference between the two main types of aquatic snails. Prosobranch snails have a long incurrent siphon (tube) that draws water into the mantle (the tissue connecting the body to the shell), where gills extract oxygen. Thus they are able to “breathe” underwater much like a clam. Another key characteristic of prosobranch snails is the operculum, a hard, horny, rounded “trapdoor” attached to the foot that seals the opening when the animal retracts into the shell. It functions to protect the snail from predators as well as to keep it from drying out if it should be stranded out of water for a time.
Habitat and Conservation
People are intrigued by snails, and many think of snails symbolically as a representative of “slowness.”
The shells of snails (especially those of some of the spectacular and colorful marine species) are prized by collectors and made into jewelry and other decorative objects.
In old-time Ozark dialect, water snails were commonly called "pinnywinkles," which is one of many examples of antique forms of English that survived from early colonial days in the then-culturally isolated Ozark hills. It is basically the same as the Old English word "pinewinkle."
Aquatic snails play an intermediate role in aquatic food chains, eating plants and then becoming food for larger animals.
Several types of fishes have specialized throat teeth for cracking snail shells.
Some birds and other animals eat snails, too.