Female chimpanzees can be as violent and demonic as males, shattering the stereotype that males are the more aggressive of the species.
While studying chimps in the Budongo Forest, Uganda, University of St Andrews scientists found that females are as likely to be aggressive as males in a bid to protect their territory or offspring. The revelation disproves the age-old theory that male chimps are the more violent of our closest-living relative.
St Andrews psychologists Simon Townsend, Katie Slocombe and Klaus Zuberbühler, together with Melissa Emery Thompson from Harvard University, discovered instances of female chimpanzees killing the offspring of incoming mothers, generally viewed as a male trait.
Only three previous instances of lethal aggression in wild female chimpanzees have been documented in the last 50 years of research. Similar behaviour was described by eminent primatologist Jane Goodall at Gombe Stream National Park in the 1970s but her observations had long been disregarded as inconsistent and pathological.
Simon Townsend said, “There is a widespread belief in scientific literature that male and female chimpanzees differ greatly in their nature. It’s true that males are much more often seen to engage in extreme physical violence than females, and this has led to the notion of violent and demonic males in contrast to quite peaceful females. However, our research shows that, under the right socio-ecological circumstances, these chimp gender stereotypes collapse completely. If their resources are under threat, females can become just as violently aggressive as males”.
However, the research suggests that such extreme acts of aggression only occur under very specific circumstances. Over the past few years, the study group has experienced high-levels of female immigration into the Sonso community, probably due to the collapse of one or more neighbouring communities, which increased competition for food and other resources to intolerable levels.
Simon Townsend explained, “Rapid demographic changes have taken place at Budongo over the last 10 years, specifically over the last five years with up to 13 immigrant females entering the Sonso community. We believe that this influx of females, some with dependant offspring, has put pressure on food and mate resources and consequently, the Sonso resident females have acted aggressively. Because these observations are very rare, it is impossible to predict when another instance might occur. However we are very interested in keeping a close eye on levels of female aggression in the Sonso community especially in the instances when new females attempt to immigrate”.
The findings appear in the 15 May 2007 issue of ‘Current Biology’, published by Cell Press.
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