Mothers and …
Hrdy discovered, among other things, that dominant males in a group are challenged from time to time by roving adventurers who can mate only by defeating them. If defeated, the former leaders slink away, often wounded, while their successors attack and kill all infants under six months old. This brings their mothers back into heat, and the slain infants are supplanted by the new males’ offspring. Females resist this bravely, but to little avail.
If such behavior had been limited to langurs, it might have been an anomaly. But thanks in no small part to Hrdy’s leadership, it was also documented in chimpanzees, patas monkeys, lions, and many other species. Competitive infanticide was seen as a dark side of Darwinism, and a confirmation that no part of nature is free from the amoral logic of natural selection.
Mothers and Others: The Evolutionary Origins of Mutual Understanding
by Sarah Blaffer Hrdy
Belknap Press/ Harvard University Press, 422 pp., $29.95; $19.95 (paper)