Boy will be boys: sex differences in wild infant chimpanzee social interactions.
Sex differences in the behaviour of human children are a hotly debated and often controversial topic. However, several recent studies have documented a biological basis to key aspects of child social behaviour. To further explore the evolutionary basis of such differences, we investigated sex differences in sociability in wild chimpanzee,Pan troglodytes schweinfurthii, infants at Gombe National Park, Tanzania. We used a long-term data set on mother-infant behaviour to analyse the diversity of infant chimpanzee social partners from age 30 to 36 months. Male infants (N= 12) interacted with significantly more individuals than female infants did (N= 8), even when maternal sociability was controlled for. Furthermore, male infants interacted with significantly more adult males than female infants did. Our data indicate that the well-documented sex differences in adult chimpanzee social tendencies begin to appear quite early in development. Furthermore, these data suggest that the behavioural sex differences of human children are fundamentally rooted in our biological and evolutionary heritage.
Department of Psychology and Biological Foundations of Behavior Program, Franklin & Marshall College, Lancaster, PA, U.S.A ; Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, U.S.A.
Elizabeth V
EV
Lonsdorf
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, U.S.A.
Karen E
KE
Anderson
Center for the Advanced Study of Hominid Paleobiology, The George Washington University, Washington, D.C., U.S.A.
Margaret A
MA
Stanton
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, U.S.A.
Marisa
M
Shender
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, U.S.A ; Committee on Evolutionary Biology, University of Chicago, Chicago, IL, U.S.A.
Matthew R
MR
Heintz
The Jane Goodall Institute, Vienna, VA, U.S.A.
Jane
J
Goodall
Center for the Advanced Study of Hominid Paleobiology, The George Washington University, Washington, D.C., U.S.A.
Carson M
CM
Murray
Pan troglodytes schweinfurthii; chimpanzee; mother–infant interaction; sex difference; social behaviour