Experimental field evidence of interspecific aggression between two species of kangaroo rat (Dipodomys).

The competitive coexistence of heteromyid rodents has been primarily ascribed to differential utilization of resources such as microhabitats and seeds. An examination of the use of space by the kangaroo rat Dipodomys merriami indicates this species is aggressively subordinate to a larger species, Dipodomys spectabilis and is excluded from the larger species home range during the crtical fall harvesting season. These experiments suggest that interspecific aggression may be involved in the coexistence of these species. Additional evidence is presented that small scale spatial variations in resource productivity may promote the coexistence of these two species.