Snails are gastropods that come in many thousands of species, from those that crawl on land to those living in freshwater and saltwater. Different types of snails move in different ways, and some can swim. The part of the snail that is visible outside of its shell, the foot, it the snail's primary means of getting around whether on land or in water.
Terrestrial snails are found on land, often crawling through the garden. They're kept as pets in terrariums. These snails are not known to be able to swim in any way. Instead, a terrestrial snail uses its foot organ to crawl along the ground and up and down plants. Though we know snails to be slow creatures and speak of things that take too long as "moving at a snail’s pace,” terrestrial snails are actually relatively quick. One species can move at 6.4 inches per minute when pursuing prey. Now that's fast. Though terrestrial snails do not swim, terrestrial pet snails like to have a bowl of water for drinking and for bathing, though it is not required. Terrestrial snails can drown in too much water, so if you provide a water bowl, it should be shallow and not easily tipped when crawled upon by the snail.
Freshwater snails, unlike terrestrial snails, live in water-filled aquariums if not freshwater bodies such as ponds. As pets in a fish tank, freshwater snails feed by crawling along surfaces in the tank using their foot organs, keeping the environment clean. In addition to crawling on surfaces, some freshwater species of snail can "crawl" on the water surface. Instead of using their foot organs, these species use the buoyancy of their shells to move along the underside of the water and graze on algae. Although this is not true swimming behavior, it is a type of water locomotion.
Sea snails are surprising species that look and behave quite differently from shelled terrestrial snails and freshwater snails. Sea snails have no shells, or very slight shells, and instead use highly specialized foot organs to float or truly swim in the water. The sea hare, a close snail relative, has fin-type growths around its foot that can move to create a swimming motion. Like terrestrial snails and freshwater snails, some species of sea snails and related marine gastropods can be kept as pets in appropriate tanks.
Other Gastropod Locomotion
Crawling on land, crawling on water, floating and swimming make up the primary locomotive behaviors of snails, all dependent on the specific species and environment of the snail. Swimming is one of the more surprising motions of a gastropod, but jumping may be even more so. A common garden snail can leave a stuttered slime trail when crawling on dry ground, making it look as though the snail has hopped. The conch, which is a shelled gastropod closely related to the snail, push into the ocean floor with part of its foot to leap forward. Snails and other gastropods appear simple and peaceful when we observe them in a garden, terrarium or aquarium, but they exhibit a great variety of behaviors.
E. Anne Hunter has more than a decade of experience in education, with a focus on visual design and instructional technology. She holds a master's degree in education. Hunter has contributed to several professional publications, covering education, design, music and fitness, among other topics.