The male Fiddler Crab (Uca crenulata), or Cangrejo violinista in Spanish, is a small marine crustacean that waves its one gigantic claw to attract female attention or to tell other males to back off. Their eyeballs on stalks may look strange, but they allow Fiddler Crabs to see in all directions and watch for predators. They feed on decaying organic matter (bits of other mudflat plants and animals) and are preyed upon by various birds that inhabit the brackish intertidal mudflats. 

Did you know? As the Fiddler Crab feeds, it filters the top layer of the mud and extracts organic material to eat, compressing the clean mud into little balls you see on the mud flats.

If you would like to see Fiddler Crabs in their natural habitat, take a walk or guided hike at the Tijuana River Natural Estuarine Research Reserve.

PHOTO CREDIT: Jerry Jacobs