The distances at which individual hermit crabs (Clibanarius tricolor and C. antillensis) showed agonistic behavior patterns was recorded after the animals had been held at one of two densities for a week. 1) Behavior patterns differed significantly in the average distance of separation when they were executed. 2) For almost all patterns, there was considerable variability in the distances at which they were shown. 3) Part of this variance in distances was due to the behavior of the other crab. 4) Density treatment affected the distances at which behavior patterns were shown, the crabs held at the lower density having greater distances. Apparently as a result, lower density crabs lost more interactions. 5) The distances at which behavior patterns were shown were not correlated with either absolute or relative size of the acting crab. 6) Comparison of distances in intraspecific and interspecific interactions indicated very similar behavior in the two species, except that C. antillensis was not as clearly affected by the density treatment.