Gomes said: "Our results strongly suggest that wild chimpanzees exchange meat for sex, and do so on a long-term basis. Males who shared meat with females doubled their mating success, whereas females, who had difficulty obtaining meat on their own, increased their caloric intake, without suffering the energetic costs and potential risk of injury related to hunting."

"Previous studies might not have found a relationship between mating success and meat sharing because they focused on short-term exchanges; or perhaps because in those groups access to females was driven by male coercion so females rarely chose their mating partners," she added.

Boesch concluded: "Our findings add to the ever-growing evidence suggesting that chimpanzees can think in the past and the future and that this influences their present behavior."

"These findings are bound to have an impact on our current knowledge about relationships between men and women; and similar studies will determine if the direct nutritional benefits that women receive from hunters in human hunter-gatherer societies could also be driving the relationship between reproductive success and good hunting skills," concluded Gomes.

Editor:Liu Fang