Even if they have nothing to lose, chimpanzees opt not to help strangers, according to a team that studied unrelated chimps at two research facilities.
The new findings complement earlier studies indicating that chimps cooperate mainly with close relatives and partners in tit-for-tat exchanges, say Joan B. Silk of the University of California, Los Angeles and her colleagues. Even if chimps, like some monkeys (SN: 9/20/03, p. 181: Unfair Trade: Monkeys demand equitable exchanges), detest getting a lesser reward from experimenters than other chimps do, they show no desire to spread their own wealth with unrelated chimps, the scientists report in the Oct. 27 Nature.
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