Territoriality and Behavior in a Population of Pikas (Ochotona princeps)

Abstract

Pikas (Ochotona princeps) were studied on three talus slopes during the summers of 1974 and 1975 in the vicinity of the Rocky Mountain Biological Laboratory, 2,900 m, Gunnison Co., Colorado. The pattern of social organization among marked resident adults was one where males and females maintained territories, which excluded other residents of the same sex but overlapped considerably with residents of the opposite sex forming a pair-wise distribution. Dominance relationships were dependent upon age, residency, and sex; resident adults always expelled intruders of the same sex but were never observed to be dominant outside their territories. Aggressive behavior, exhibited by chases and fights, was the predominant factor in maintenance of territories. Scent-marking and vocalizations occurred in a variety of circumstances and scent-marks did not deter intrusion of invading pikas. Vocalization and olfaction are proposed as means to modify aggressive behavior through sexual and individual recognition.