Bernard Castelein / West African fiddler crab (Uca tangeri) male with large claw, Gambia.

Bernard Castelein / West African fiddler crab (Uca tangeri) male with large claw, Gambia.

Bernard Castelein / West African fiddler crab (Uca tangeri), Gambia.

Nick Upton / Male European Fiddler Crab (Uca tangeri) waving its large right claw. Tavira, Algarve, Portugal, June.

Kim Taylor / Fiddler crab {Uca tangeri} male feeding. Sierra Leone, Africa.

Kim Taylor / Fiddler crabs {Uca tangeri} feeding in mud at low tide. Africa.

Denis-Huot / Fiddler crab (Uca tangeri) males near Barbate, Cadix, Andalucia, Spain, June.

Philippe Clement / Male Fiddler crab (Uca tangeri) feeding on a beach. Captive.

Philippe Clement / West African fiddler crab (Uca tangeri / Gelasimus cimatodus ) female on muddy beach at low tide, native to coast of West Africa. Captive

Philippe Clement / West African fiddler crab (Uca tangeri / Gelasimus cimatodus) male with huge claw on muddy beach, native to coast of West Africa. Captive