Fiddler crabs get their name from the male's large claw.
They use the claw to defend their burrows and to attract mates. Males have a highly ritualized combat of arm-waving, bobbing of the body, and standing with an open, upright stance. However combat rarely gets physical as there is too much risk of injury to both crabs. Ecological and Environmental Importance of Fiddler Crabs Fiddler crabs play important roles in many marsh processes. Fiddler crabs are also avid burrowers.