Clawful is a giant anthropomorphic crab with claws similar to a fiddler crab. Uca alcocki is a species of fiddler crab. Uca vocans is a species of fiddler crab. Uca perplexa is a species of fiddler crab. The difference is also much more pronounced among fiddler crab males. Save the Rat Pack!/Save the Fiddler Crab! An extensively studied example is the fiddler crab. Crane retained the fiddler crab specimens until her book was published in 1975.