INTERSPECIFIC AGONISTIC BEHAVIOR IN SMALL MAMMALS IN A MEXICAN HIGH-ELEVATIONAL GRASSLAND

Field trials were conducted throughout an annual cycle to study the ro le of agonistic behaviour in explaining the relative abundance of the volcano mouse (Neotomodon alstoni) in a small mammal community in high -altitude grasslands of central Mexico. Intrasexual contests between N . alstoni and three other sympatric rodents (Peromyscus melanotis, Mic rotus mexicanus, and Reithrodontomys megalotis) were performed. Male a nd female P. melanotis (100 and 67% of contests, respectively) and M. mexicanus (82 and 100%) were aggressively dominant over N. alstoni, wh ereas R, megalotis (80 and 100%) were not aggressive. Agonistic behavi our in this species did not explain its greater abundance in the commu nity.