Cepaea nemoralis

[3] It is one of the most common large species of land snail in Europe, and has been introduced to North America.

[6] The colour of the shell is highly variable; it ranges from brown, through pink, to yellow or even whitish, with or without one to five dark-brown bands.

[9] The thickened and slightly out-turned apertural lip of adults is usually dark brown, but can be white in some regions.

Cepaea nemoralis tends to grow larger, but usually the species can most easily be recognised by the colour of the lip of adult shells.

Also, M. sylvatica is distinct in having a small blunt tooth in its aperture, whilst the lowest brown band on the shell of C. vindobonensis lies noticeably closer to the columella than in Cepaea.

[15] The explanation might be camouflage or climatic selection: paler, more reflective colours in sunny environments reduce water loss and overheating.

Researchers have variously argued that the cause is random genetic drift and founder effects, different selection pressures in different areas with mixing by migration, and balanced polymorphism.

[17][18] Thus it is known from most of the Iberian Peninsula,[19] France, Great Britain, Ireland, Belgium, the Netherlands, Germany, Denmark, southern Sweden and Norway, Switzerland, Austria, the Czech Republic,[20][21] Hungary, Bosnia, Croatia, and the northern half of Italy.

[8] Starting in 1857, there have been multiple introductions to North America, where it now occurs widely in Canada (from British Columbia to Newfoundland; in Ontario it is a pest of vineyards) and in the north-eastern part of the US, with further occurrences further south (e.g. California, Colorado, Texas and South Carolina).

[12] This is a very common and widespread species in Western Europe, occupying a wide range of habitats from coastal dunes to woodlands with full canopy cover, including gardens and abandoned land.

[6] Mating tends to be concentrated in late spring and early summer, though it can continue through the autumn.

[6] The snails may store the sperm they receive from their partner for some time, and individual broods can have mixed paternity.

[36] The most common predator of Cepaea nemoralis is the song thrush (Turdus philomelos), but other predators include rook (Corvus frugilegus), brown rat (Rattus norvegicus), European hedgehog (Erinaceus europaeus), wood/field mouse (Apodemus sylvaticus), moles (Talpidae), rabbits (Leporidae), phorid flies (Phoridae), maggots.

Snail traversing a leaf.
Mating