fiddler crab

Emily K on April 15, 2007

The male fiddler crab’s large claw (also called a cheliped), is used for courtship and signaling. It is clearly visible from a distance as the crab waves it up and down to attract females. Depending on the species, even if a male fiddler crab loses his cheliped, his other claw will grow to become a giant one, and the lost claw will regenerate into a small one; or he’ll simply grow a large claw from the same place.

There is a downside to having one giant claw. It is too large to pick up food efficiently, so he can only eat with his smaller claw. Fiddler crabs use their smaller claw to bring bits of sediment to their mouth and sift out anything edible. If a male fiddler crab had two giant claws or no smaller claw, it would be unable to feed itself. Since female fiddler crabs have two small claws, it can forage twice as efficiently as the males.