Double infanticide in a free-ranging group of buffy-headed marmosets, Callithrix flaviceps

This study describes two infanticides in a free-ranging group of Callithrix flaviceps. In November 2008, four females gave birth within a period of approximately 10 days. On the day after the third birth, the new mother was attacked by an unidentified individual, resulting in the death of one of her infants due to a bite to the top of the head. Five days later, the fourth female gave birth to twins, and the next day, the more socially dominant of the breeding females was observed ingesting the head of one of these infants. All other infants survived until the end of the study. With the exception of the unusual number of births and attacks, the behaviour appeared typical of that recorded in other marmosets, where socially dominant breeding females attack the offspring of subordinates, apparently as a strategy aimed at reducing competition for the services of infant caregivers.