Common periwinkle

Quite often, periwinkles can survive large injuries to their shells. In such cases the shell is repaired and a scar is visible on the shell. Even if enemies cannot damage the shell, certain creatures i.e. fish that are quick, can bite off the periwinkles foot before it retracts it into the shell. Crabs sometimes manage to stick in one of their claws into the shell aperture and pull out the soft parts, which wading birds often do with the help of their long beaks.
    It is quite common in some countries like France and Great Britian that people collect and eat periwinkles.
    In its natural environment, the periwinkle is seldom older than 3 years, but in an aquarium it is known that an individual was as old as 20 years.

Worms in their shell

Quite often it is noticed that the spires on large individuals are perforated with small holes that haved been bored by a little polychaete. If the shell is submerged in the water it is possible for the worm to stick out two long tentacles and catch microscopic particles of food suspended in the surrounding water.

Pelagic larvae

Females grow quicker and larger than males. Reproduction takes place from the spring and until the middle of the summer. During this period it is possible to see males trying to mate with both males and females of their own species; and with other specie of periwinkle. Successful mating entails that the male creeps up onto the right side of the females shell and from that position place its long penis into the shell aperture of the female. The female stores the sperm in a small bladder and can fertilize several batches of eggs over a period of several days after mating.

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Returns home?

Glue their shell

Can survive in ice

Eats brittle algae

The shell protects

Worms in their shell

Pelagic larvae

Many are


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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson