Uca Pugilator

The sand fiddler crab, also classified as Leptuca pugilator, is a species of fiddler crab found along the Atlantic coast of North America from Massachusetts to the Gulf of Mexico, with reports also from the Bahamas and warmer Atlantic waters off West Africa. It lives in burrows dug into coastal and estuarine mud flats, sometimes at very high population densities. Males carry one greatly enlarged claw, up to 1.6 inches long, with a notably smooth inner surface that distinguishes it from related species, and they use this claw to defend territory and fight rival males, regrowing it if it is lost in combat.