Wild Harris

Link to Rocky Shore Animals

Several species of crab have developed an extraordinary ability to use discarded sea snail shells as an additional means of protection. The body that is covered by the snail shell is fairly soft, and twisted to match the spiral shape of the shell. The front end of a hermit crab is by contrast heavily armoured, and when it withdraws into the shell the entrance is guarded by the crab's claws.

When a hermit crab outgrows its snail shell home it will need to find a bigger one. The crab needs to choose its shell carefully, and will spend hours sizing up suitable candidates before quickly moving into its new home. They have even been seen to fight with other hermit crabs over who should get the best shell. If you pick up a hermit crab it will sometimes abandon its shell in fright. If you don't put the crab down close to its shell it is unlikely to survive for long. Hermit crabs are usually found in winkle or whelk shells, although others such as tower shells are used where available, and even plastic bottle tops may be pressed into service where there are no suitable snail shells to be found.

(Photo: Sue Scott)

A small hermit crab in a winkle shell 

(Photo: Paul Tyler)

Larger hermit crabs need larger homes - this one lives in an old whelk shell. 

by Paul Tyler

Link to Rocky Shore Animals