Infanticide is known to occur in many primate species, but is generally thought of as a male trait. An exception in the realm of chimpanzee behavior was famously noted in the 1970s by Jane Goodall in her observations of Passion and Pom, a mother-daughter duo who cooperated in the killing and cannibalization of at least two infant offspring of other females. In the absence of significant additional evidence for such behavior among female chimpanzees, speculation had been that female-led infanticide represented pathological behavior, or was a means of obtaining nutritional advantage under some circumstances.
As the result of new field work involving the Sonso chimpanzee community in Budongo Forest in Uganda, the St. Andrews researchers now report instances of three female-led infanticidal attacks. Alerted to the killings by sounds of chimpanzee screams, the researchers directly observed one infanticide, and found strong circumstantial evidence for two others. Evidence suggested that in two of the cases, the killings were perpetrated by groups of resident females against "stranger" females from outside the resident group. Infants were taken from the mothers, who were injured in at least two of the attacks; in at least one case, adult males in the area exhibited displaying behavior, with one old male unsuccessfully attempting to separate the females.
The authors point out that these new observations indicate that such female-led infanticides are neither the result of isolated, pathological behaviors nor the by-product of male aggression, but instead app