At the front of the body is the head, which has one or two pairs of retractable tentacles: The longer, upper pair bears the snail’s eyes the shorter, lower pair is used for chemical sensing - taste and smell. Each turn of the shell is called a “whorl.”Īfter the shell, the most obvious part of a snail is its muscular foot, with which the snail moves by waves of muscle contractions, aided by a layer of mucus. If it goes counterclockwise, then it’s left-handed (or sinistral).
#SNAIL VS SLUG HOW TO#
Most snail species are “right-handed,” but some are “left-handed.” Here’s how to tell: If you hold the shell with the tiniest whorls (apex) facing you, and the spiral develops and widens in a clockwise direction, the shell is right-handed (or dextral). Look closely at the structure of a snail shell: One key identifier for any snail is how the shell is coiled. Long after a snail has died, and even after the shiny, colored outer layer (periostracum) of a shell has been eroded, the different species can be identified by the bleached, white mineral portion of the shell. Most are drab white, tan, gray, or brown, but some species have red, yellow, or striped shells. The aperture (opening) often has distinctive folds, teeth, and other projections. Mollusc shells are often used for identification because they are durable and have easily-seen characteristics, such as bumps, ridges, and spiraling traits. Different slug species are usually identified by the different positions and configurations of the mantle and body openings. Slug species occur in several snail families, so slugs and snails do not represent different taxonomic groups. Slugs are essentially the same thing as land snails they are simply land snail species that do not develop visible shells. In a general way, the basic body form of snails and slugs is like that of other molluscs (limpets, squids, octopuses, clams, mussels, and so on), but snails have the distinctive spiral shell. Slugs lack visible shells, while snails have coiled shells composed of hard calcium carbonate. Most people recognize land snails and slugs when they see them: They have moist, soft, elongated bodies with a definite “foot” and a head with paired tentacles.
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