Female chimpanzees are more "negative" when communicating with other females than they are with males, a U.S. researcher says. In a study, doctoral student Nicole Scott from the University of Minnesota analyzed the different gesturing strategies used by a group of females at Chester Zoo in Britain. Female chimps used more gestures of aggression when communicating with other females, she said, and "apologized" less often with gestures of reassurance. But when communicating with males, they used more expressions of greeting and submission. "When communicating with males, females sort of 'suck up' to them," Scott told the BBC. Overall behavior in males and females showed no differences in the repertoire of gestures the animals used, she said, but differences in communication appeared when individual interactions were analyzed on a gender basis. While female chimpanzees in the group studied adopted a different gesture strategy depending on the sex of a partner, the males did not, she said. She acknowledged 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.