DOMINANCE, AGE AND AGGRESSION AMONG FEMALE PRONGHORN, ANTILOCAPRA-AMERICANA (FAMILY, ANTILOCAPRIDAE)

The relationships among dominance, age and aggressive behaviour of mar ked, female pronghorn (Antilocapra americana; Family Antilocapridae) w ere studied in north central Colorado, Females formed dominance hierar chies with few circular relationships. Unlike other female ungulates, dominance rank was not correlated with age. Dominance rank was negativ ely correlated with rate of aggression initiated in summer and winter; however, aggressiveness as an individual trait was not related to dom inance. Older females received higher rates of aggression than younger females in summer and winter. During the rut, dominance rank was corr elated with rate of aggression received but not with rate of aggressio n initiated. Patterns of aggression that differ by season within a giv en hierarchy of dominance relationships suggest a different cause or f unction of aggressive behaviour in different seasons.