The shore crabs colours and patterns

Shore crabs can have a variety of colours and patterns on their shells. Above are two shore crabs that live on a sand bottom. The crab on the left is quite young, the carapace of which is about 1cm in width, while the crab on the right is somewhat larger, but not yet an adult.

Young crabs have a certain ability to alter their colour and pattern by either concentrating or spreading a pigment in the shell. Obvious patterns in the shell as depicted above are most common among young crabs.

These crabs are both older and larger (approx. 3 cm). The one on the left is climbing on a colony of barnacles and coralline crusts. The one on the right is climbing on toothed wrack.

Boiled or sun-dried shells are usually orange in colour.

When the crabs shell becames to tight, the shell is sloughed, and a new larger one is formed.

The male carries the female for a few days before mating.

The female carries her eggs under her posterior.

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