Adaptation

Land snails play an important role in cycling calcium in their habitats.  Many snails use calcium for external shell development and reproduction which they obtain from their environment.  When calcium levels are low in the environment snails will resort to use calcium from their own internal organs (Hotopp, 2002).   

Land snails have many predators which include ground beetles, salamanders, shrews, birds and wild turkey (Hotopp, 2002).  Some land snails are even eaten by humans!  The carbon carbonate shell of a snail is their best defense against predators.  When attacked snails try to protect themselves by retracting their soft body parts inside their shell.  Snails then close their shell using a door like structure called an operculum.  This enables the snail to be completely incased their shell to protect themselves from predators.  The operculum is also used in snails (aquatic and terrestrial) to retain moisture.

Terrestrial snails are belly-footed.  They move by progressive waves of contraction and expansion of a ventral, muscular foot.  The muscular foot is located on the anterior portion of the snail’s body.  Snails and slugs often excrete mucus to reduce friction.  This is known as “sliding on slime” (Martin, 2000).

Terrestrial snails have low dispersal since they have slow mobility rates moving speeds around 1mm/s.  They only travel short distances only when conditions are favorable to find food or for reproduction (NatureServe explorer, 2009).  This causes land snails to adapt to their environment more often than migrating to a new location (Goodfriend, 1986).

Terrestrial snails have retractable eyes at end of tentacles which aquatic snails do not possess (Poweshiek skipper project, 2005).  Helicodicus snails lack eye pigmentation and have relatively short tentacles(Pilsbry, 1998).