Hunting and predation in a fiddler crab


Fiddler crabs are known primarily to be deposit feeders. They eat detritus, bacteria, and other small particles of organic material found in the sandy or muddy substrate on which they live. They have highly specialized mouthparts used to separate edible matter from nondigestable material. Here we provide evidence of cannibalism and predation in a fiddler crab, Uca annulipes. We additionally provide the first evidence of a fiddler crab hunting shrimp and insects. This study is an exemplary reminder that, even though an animal may have evolved highly specialized feeding traits, this need not preclude it from opportunistically acting as a generalist feeder.

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We thank Isobel Booksmythe and Jessica Bolton for assistance in the field. Research was funded by the Australian Research Council (to P.R.Y.B. and M.D.J.).

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Correspondence to R. N. C. Milner.

Electronic supplementary material

A number of Uca annulipes males subdue and fight over a Penaeus indicus shrimp (MPG 8,570 kb)

Large male Uca annulipes feeds on a large dead male conspecific before dragging it into his burrow (MPG 3,448 kb)

Large male Uca annulipes chases and catches a small female conspecific before crushing her with his major claw and carrying her back into his burrow (MPG 12,434 kb)

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Milner, R.N.C., Detto, T., Jennions, M.D. et al. Hunting and predation in a fiddler crab. J Ethol 28, 171 (2010).

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  • Cannibalism
  • Feeding
  • Fiddler crab
  • Predation
  • Uca annulipes