Field laboratory studies on the agonistic behavior of the ghost crab, Ocypode quadrata

The most frequently observed field social behavior in the Ghost Crab, Ocypode quadrata is the agonistic (aggression-defense) encounter. This encounter includes the Still Chela Forward display (Wright 1968), the ritualized fight, displacement or out-of-context movements, and flight. As the crabs are paired and allowed limited daily laboratory interaction, significant changes take place in these components. Display frequency decreases and there is a loss of display stereotypy. Fight frequency increases and there is, in some groups, a loss of fight ritualization. Escape activity increases during the period of greatest change in the display and the fight and decreases as behavior stabilizes. These changes appear to be the result of habituitive processes and serve to adapt the crab's behavior to the laboratory environment.