Mountain Gorillas Teach a Lesson about Gendered Behavior

By Nathan H. Lents and Stacy Rosenbaum

[A longer version of this post can be found here.]

The mountain gorillas of Virunga National Park in Rwanda have been under continuous intense scientific scrutiny since George Schaller and Dian Fossey began their pioneering work in the 1950s. Fossey was the subject of the Oscar-nominated biopic Gorillas in the Mist.

Dian Fossey observing Mountain Gorillas Image Source: Dian Fossey Gorilla Fund International

Male gorillas are more than twice as large as females, underscoring their evolutionary legacy of male contest competition and polygyny. Indeed, gorillas were long thought to exist almost exclusively in harems, small multi-female groups led by one powerful silverback. Upon reaching adulthood, young males typically leave their birth group and go through a solitary period before attempting to take over a harem or start a group of their own. Most are not successful.

Beginning in the 1990s, some younger males stopped leaving their groups. Scientists began observing very large groups including several adult males and females living together in relative harmony. Some groups hosted up to nine adult males, and one group topped out at 66 total animals. Twenty years in, this trend shows no sign of reversing and currently involves one-fourth of the mountain gorilla population at Virunga.

A Mountain Gorilla community in Virunga National Park Photo Credit: Dian Fossey Gorilla Fund International
A Mountain Gorilla community in Virunga National Park
Photo Credit: Dian Fossey Gorilla Fund International

This raises very pointed questions for the field of evolutionary psychology. Central to evolutionary psychological theory is the notion that behaviors are the product of natural selective forces that reward reproductive success. Many controversial corollaries have sprung from that seemingly straightforward claim, including that some behavioral distinctions between men and women might be the result of innate, naturally selected differences. Intangible phenomena like professional ambition, competitive tendencies, and desire for a rewarding family life, along with more concrete cognitive abilities such as spatial and quantitative reasoning, are sometimes invoked in the otherwise thoughtful conversations about why we don’t see more female astrophysicists on the Harvard faculty. Continue reading “Mountain Gorillas Teach a Lesson about Gendered Behavior”