Calling-crab
Guides
Uca
Narrow-fronted Fiddler Crabs, fiddler crabs, calling crabs
Uca is a genus of semi-terrestrial marine crabs comprising approximately 100 species, commonly known as fiddler crabs or calling crabs. Males are distinguished by one greatly enlarged claw used for visual displays and combat. These small crabs inhabit intertidal zones worldwide, where they construct burrows and feed on organic material in surface sediments. Their burrowing activity contributes significantly to sediment turnover and nutrient cycling in coastal ecosystems.