Does Size Matter? Sexual Dimorphism in Human Evolution

See the recorded webcasts:

Dialogue Webcas

Among our closest animal relatives, males are bigger than females and have bigger natural weapons in their fang-like canine teeth. But the amount of difference varies in different species. In apes where dominant males jealously guard and fight over females, the difference is large (gorillas, orangutans). Where males and females have similar options in choosing mates (gibbons, chimpanzees, bonobos), the difference between the sexes is small.

The difference is small in humans, as in chimpanzees and bonobos. But has this always been the case? Are we descended from pair-bonded, monogamous animals— or from creatures in which dominant males fought each other for possession of females? What do fossils and living animals tell us about the mating patterns of our own forebears? These questions are hotly debated, because the pattern of sex differences in early human ancestors is not like that seen in any living ape.


APRIL 26, 2012 2:30 PM

Two experts on the evolution of sexual dimorphism, Dr. J. Michael Plavcan (University of Arkansas) and Dr. Phil Reno (Pennsylvania State University), will discuss and debate their opposing views on these issues. Their statements will be available online a week before the Dialogues. After reading them, you can send in questions via e-mail to Matt Cartmill or find us on Facebook.

Return to on April 26 to see the webcast live.


APRIL 26, 2012, 4:00 PM



All members of the BU community are invited to join this public discussion, in which Drs. Plavcan and Reno will be joined by BU anthropologists Jeremy Desilva, Matt Cartmill, and Cheryl Knott for a discussion of sex differences in human evolution and its implications for the evolution of human behavior. Come and question the experts — and stay to join us for the concluding reception.