AbstractThree abortions and the death of a vigorous infant occurred in a baboon (Papio cynocephalus) group in Amboseli National Park, Kenya, within the two weeks following the immigration of an aggressive adult male. The immigrant male attained top‐ranking dominance status in the group prior to these events. Circumstantial observations suggest that the reproductive losses were related to persistent intense aggression from the immigrant adult male. In the past ten years, only three other miscarriages have occurred in Amboseli. Inducement of abortion is discussed as a reproductive tactic that may be available to males of mammalian species whose life histories favor the evolution of infant‐killing by ma