Abstract
Munida sarsi is a deep water, bottom-living galatheid. Its aggressive behavior was observed for several weeks in aquaria that could only partially mimic its natural habitat. It threatens by extending its chelipeds, snapping its pincers, and raising its abdomen off the mud. The cheliped extension appears to be the indispensible part of the display. Threatening individuals spar with each other, and though such bouts are unpredictable in occurrence, duration, and outcome, they are mutually stimulating, harmless, and involve a series of stereotyped movements. The aggressive behavior of M. sarsi seems primarily to ensure each its private space of mud on which to dig and feed.
