New research suggests male chimpanzees' aggressive behavior towards females could actually be a method of ensuring sucessful mating.
Male chimpanzees sometimes attack their female peers, resulting in serious injury, Arizona State University reported. Researchers have found males that show directed aggression at certain females mated more often with those females than less aggressive individuals, and were also more likely to be solicited by females at their time of peak fertility.
The findings suggest male aggression towards females is adaptive. To make these findings the researchers looked at DNA taken from fecal matter to determine paternity of 31 infant chimpanzees born during the study and years of observations of the Kasekela chimpanzee community in Gombe National Park, Tanzania.
The data indicated the rate at which a male directed his aggression at a female increased the pair's mating frequency and increased the change of pregnancy, but this aggression was not used to force sexual encounters and did not occur directly before or after mating.
"This indicates that males, particularly those of high rank, successfully employ a strategy of long-term sexual intimidation," said Ian Gilby, an assistant professor in the School of Human Evolution and Social Change and research affiliate with the Institute of Human Origins at Arizona State University.
The findings could indicate a female preference for dominant males, but the findings showed the aggression tactic was most successful in high-ranking males; this result suggests guarding by strong alpha males is responsible for the higher pregnancy and mating rates.
While the findings could provide insight into the origin of sexual violence in humans, the researchers warn this is not necessarily the case.
"We should be careful not to jump to conclusions. Chimpanzees are one of our closest living relatives, but 7 million years of evolution separate us, and our mating systems are very different. Nevertheless, recognizing the adaptive value of male-female aggression in chimpanzees may inevitably help us to understand, and hopefully prevent, similar behavior among humans," Gilby said.
