The Hermit Crab is possibly one of the most well-known species of crab. They are easily identified by their red colour and hairy claws and on one of my latest night dives in the Seaway I found myself mesmerized by this slow-moving, shy, foraging crab.
This particular individual, we'll name him 'Harry', was kicking back on the edge of a large "tank" and as I swam through the man-hole we came virtually face-to-face. The detail and intricate features of crabs and hermit crabs in particular is pretty amazing. Harry hung out for a little while longer but must have decided that the light and bubbles just weren't his scene and he scampered off for cover.
The hermit crab is unique to other species of crabs as their abdomen are not covered by a hard exoskeleton and is instead soft and delicate. To overcome this they spend their lives in discarded snail shells and as part of a crabs life the energy draining process of moulting must occur in order to grow. When hermit crabs do this they must go in search for a new shell to accomodate their new 'hulk-ified' bodies.
This search for a new shell is somewhat similar to searching for a mate/having an affair; they find a new shell, pick it up, turn it over, if they like what they see they jump in. However, if they decide that this new shell doesnt cut it they will return back to their old one and continue their search for the 'ultimate shell'.
If you do happen to cross paths with a Hermit Crab while diving, I highly recommend stopping for a quiet rendezvous with a "Harry" of your own.
Sarah Shark www.sarahshark.com