Adult Male Chimpanzees Kill and Eat a Male Newborn Infant: Newly Observed Intragroup Infanticide and Cannibalism in Mahale National Park, Tanzania

On 5 July 1983, the adult male chimpanzees of M group killed and ate a male newborn infant in Mahale National Park, Western Tanzania. The infant is believed to have been sired by one of the M group males. Intergroup infanticide might result in improving reproductive success by eliminating a future competitor. In the present episode, however, there is a fair possibility that the males fostered the erroneous idea that the infant had been sired by the males of another group because its mother had disappeared from M group for several months before parturition. After the infanticide, the social relationship between the mother and M group chimpanzees became more stable.