Slugs and snails are nocturnal molluscs. They are hermaphroditic, which means that they have both male and female reproductive organs. Usually, two individuals must mate for the eggs to be fertilized.
Eggs: Spherical, tiny (a few millimetres) and transparent white when freshly laid, becoming darker as
Juveniles: Identical to the adults, only smaller.
Adults: Soft, elongated bodies, from 1 to 15 cm long, depending on the species. Snails have a spiral shell, and slugs, which are greyish or brownish, do not. They have four tentacles on their heads; the upper pair are tipped with eyes and the lower pair are tactile and olfactory organs; the mouth has tiny teeth and a file-like tongue (radula); the foot, the ventral, muscled part, is equipped with a mucus gland that helps them move about.
Slugs and snails overwinter as both eggs and adults, buried in the soil and plant litter.
Each individual can lay hundreds of eggs a year. They deposit them in batches in decaying plant matter and in the soil.
The eggs hatch in three weeks to several months, depending on weather conditions. It takes from a few months to a few years for the juveniles to mature, depending on the species.