Perimenstrual Aggression in Groups of Female Rhesus Monkeys

The pioneer study of Carpenter (1942) characterized oestrous behaviour in rhesus monkeys by criteria related to increased sexual behaviour and by `increased aggressiveness . . . and wounds'. Subsequent studies of rhesus monkeys by Bernstein (1963) and Lindburg (1971) have confirmed a mid-cycle increase in behavioural arousal which appears to coincide with ovulation (as judged from subsequent pregnancy data). Loy (1970) now reports an increase in so-called `estrous behavior' both perimenstrually and at mid-cycle in free-ranging rhesus monkeys. Rowell (1963) has observed increased perimenstrual aggressive interaction, but differentiates increased aggression received during the premenstrual week from increased aggression exerted on cage mates during the week after the onset of menstruation. The present study is an attempt to relate