Japanese researchers have noted that chimpanzees offer straws and other drinking tools to fellow chimps in an adjoining chamber — an apparently altruistic act, according to PLoS ONE, a U.S. science magazine, published Wednesday.

The research may pave the way to the evolutionary study of selfless behavior in humans, said a team of Kyoto University members, including associate professor Masayuki Tanaka.

"We may be able to find out a clue (through the research) to how human beings created a society in which people cooperate with each other," said Shinya Yamamoto, a member of the team who was formerly a graduate student at Kyoto University.

The team put two chimps in two chambers separated by a glass wall with a hole. To drink juice from a container, they must use a straw or a stick to pull it closer. The tools were put in one chamber.

The team variously paired nine chimps and the result showed more than half offered the drinking tools to the other chimpanzee.

It was thought rare for chimps to spontaneously help another in trouble.