'Girl talk' in chimps often aggressive

Female chimps are more "negative" and use gestures of aggression when communicating with other females, scientists say.
Researchers analysed different gesturing strategies used by a group of females at Chester Zoo in UK and found that in female-female interactions, the chimps used more aggressive signals and "apologised" less often with gestures of reassurance.
However, they employed a more positive strategy around males, with more expressions of greeting and submission, BBC Nature reported.
"When communicating with males, females sort of 'suck up' to them," said Nicole Scott from the University of Minnesota, Minneapolis, US.
Scott video-recorded the behaviour of 17 females and five males in a group of chimps at Chester Zoo.

"I defined gesture as an expressive movement of the limbs or head and body postures produced intentionally," she said.

Scott found that females in the group adopted a different gesture strategy depending on the sex of a partner but the males did not.
This indicates that female chimpanzees are more sensitive to the sex of their partner than males, and cater their gesture use accordingly, she said.
Different "social pressures" on the sexes could explain the difference in communication strategies, she said.
For example, males might have more positive relationships with other males because of the importance of male-male alliances and maintaining high social rank in a group.

However, there may be less focus on female chimpanzees maintaining multiple, positive relationships with other females, and instead more pressure on them to form positive relationships with males.
Scott suggested the complex social behaviour seen in chimps, and highlighted in her study, may hint at our own actions.
"To speak anthropomorphically, I can certainly see some parallels in my own life: women are generally more aggressive and competitive with each other [and] men do not change their behaviour outside the context of social rank," she said, referring to studies of gesture differences in humans.
She added that her analysis of female aggression could be controversial because "there is a belief in the field that males are more aggressive than females".

"Some researchers likely will have trouble accepting my results since I show that females are also aggressive," she said. It's not that they are more aggressive, just different from males in their use of aggression," she said.
The study was published in the American Journal of Primatology.