Hobbies And Interests
Adults
Adult periwinkles are quite long lived, with a lifespan of up to 10 years. They reach maturity at about 3 years. They reach a full size of up to an inch long, depending upon the species. Periwinkles have the typical body structure of a snail, with a spiral shell, a foot and a mantle. Like many marine snails, they have gills for absorbing oxygen under water.
Reproduction
Unlike many snail species, periwinkles are not hermaphrodites; the genders are separate. In appearance, females tend to be significantly larger than the males. Fertilization takes place within the bodies of the females, in contrast to many marine creatures.
Eggs
After mating, the females lay eggs in a gelatinous coating, on a suitable platform such as algae or rocks. One batch could consist of thousands or tens of thousands of eggs.
Larvae
Periwinkles go through a larval stage, joining the zooplankton for about six weeks. Here they feed on other tiny organisms. The periwinkles then metamorphose into miniature versions of the adults. Their shells grow as the periwinkles grow.