ABSTRACT
Infant killing among primates has been reported most often in species that form groups that have only one breeding male, such as langurs, redtail monkeys, blue monkeys, and gorillas (reviewed by Hrdy, 1981; Butynski, 1982). One interpretation, derived from Sugiyama’s descrip tion (1965b) of infanticide in langurs (Presbytis entellus), is that infant killing is a reproductive strategy of advantage to males when they migrate into a new group, and that it has been favored by sexual selec tion (Hrdy, 1974). In some species, females will resume menstrual cycles soon after their infants die and suckling ceases, and male newcomers then gain a correspondingly earlier opportunity to sire the females’ next infants (e.g., Sugiyama, 1965b). Infant killing, therefore, would be particularly advantageous to males whose reproductive tenure is brief (Hrdy, 1974; Chapman and Hausfater, 1979). The major alternative explanation states that such killings result from social disturbance aris ing at high population density, ultimately caused by human alteration of the habitat (e.g., Curtin and Dolhinow, 1978). An evaluation of these and other hypotheses to explain infant killing in langurs is given by Hausfater and Vogel (1982).
