Canon EOS 550D, 1/640 s, f/6.3, 300 mm
Photo taken in Gambia, Africa, February 2011.
Found in mangroves, salt marshes, and on sandy or muddy beaches of West Africa, the Western Atlantic, Eastern Pacific and Indo-Pacific, fiddler crabs are easily recognized by their distinctively asymmetric claws.
Fiddler crabs communicate by a sequence of waves and gestures; males have an oversized claw or cheliped; used in clashes of ritualised combat of courtship over a female and signal their intentions between conspecifics. The movement of the smaller claw from ground to mouth during feeding underlines the crabs’ common name; it seems that animal plays the larger claw somewhat like a fiddle. (WIKIPEDIA)