Infant carrying in a polygynous group of common marmosets (Callithrix jacchus)

In a captive group of common marmosets (Callithrix jacchus), consisting of six group members and the three infants of the two breeding females, we analyzed participation of all group members in infant carrying, and suckling by the two breeding females. During the first two weeks of the infants' lives, the two breeding females carried their own infant(s) almost exclusively due primarily to the mutual avoidance by the two females. At the beginning of the third week of the infants' lives nearly all group members began to carry all infants to a relatively high degree and both breeding females suckled all infants. The results indicate that the greater energetic demands in rearing three infants simultaneously are compensated by an extended division of labor among group members. All breeding animals preferred to carry and to suckle the infants according to kinship predictions. However, observed preferences of nonbreeding group members in infant carrying seemed not to be related to different degrees of genetic relatedness.