Infanticide and cannibalism in a free‐ranging plurally breeding group of common marmosets (Callithrix Jacchus)

Our study presents a detailed description of infanticide and cannibalism in a free‐ranging plurally breeding group of Callithrix jacchus . The 1‐month‐old infant was the daughter of the dominant female, and was attacked by the group's second breeding female. Two months later, the latter gave birth to twins and appeared to have become the dominant female. These findings confirm and extend previous reports of infanticide by pregnant female marmosets, and indicate that infants of dominant breeding female, as well as those of subordinate females, are vulnerable to infanticide in plurally breeding groups. With respect to the cannibalism, this act seemed to be mainly a response to the prompt availability of food, represented by the killed infant. Am. J. Primatol. 69:945–952, 2007.