科学家发现红毛猩猩能进行最原始的代币交易。
红毛猩猩属猿族，与大猩猩、黑猩猩及矮黑猩猩一起被称为"人类最直系的亲属"。目前只在印度尼西亚的婆罗洲低地和苏门答腊洲有少量红毛猩猩存活，全世界只剩下不到3万只。
英国皇家学会期刊《生物学快报》最新一期上刊登的研究结果说，德国一家动物园里被训练用代币来交换食物的红毛猩猩会根据自己所得食物的多少，拿出一些代币为其伙伴交换食物。
德国莱比锡动物园的一对红猩猩被教会识别三种不同的代币。
其中一种是用来为自己换取香蕉的，另一种是用来为其伙伴换取香蕉的，第三种是没有任何价值的。最初，母猩猩非常乐意用自己的代币为公猩猩换取香蕉，有时公猩猩还鼓励母猩猩花她的代币。但是，公猩猩却不大愿意用自己的代币为母猩猩换取香蕉。在母猩猩变得不大愿意花自己的代币为公猩猩换香蕉后，公猩猩开始用自己的代币换香蕉，直到双方的代币花到差不多相同的时候为止。科学家说，这两只红毛猩猩显然是在给与的背后进行讨价还价的算计。
据此，科学家得到结论说，并不是只有人类才会在付出时会有所算计，并不是只有人类在与他人合作时希望从对方得到回报。红毛猩猩也会这样。
然而，与红猩猩相比，其他类人猿——黑猩猩、大猩猩和矮黑猩猩则不大可能会这样做。（生物谷Bioon.com）
生物谷推荐原始出处：
Biology Letters，DOI: 10.1098/rsbl.2008.0644，V. Dufour，J. Call
Calculated reciprocity after all: computation behind token transfers in orang-utans
V. Dufour1, 2, M. Pelé2, M. Neumann3, B. Thierry2, J. Call3
1 School of Psychology, University of St Andrews, St Andrews, Fife KY16 9JP, UK
2 Département of Ecologie, Physiologie & Ethologie, IPHC, CNRS, Université Louis Pasteur de Strasbourg, 67087 Cedex, France
3 Max Planck Institute for Evolutionary Anthropology, 01403 Leipzig, Germany
Transfers and services are frequent in the animal kingdom. However, there is no clear evidence in animals that such transactions are based on weighing costs and benefits when giving or returning favours and keeping track of them over time (i.e. calculated reciprocity). We tested two orang-utans (Pongo pygmaeus abelii) in a token-exchange paradigm, in which each individual could exchange a token for food with the experimenter but only after first obtaining the token from the other orang-utan. Each orang-utan possessed tokens valuable to their partner but useless to themselves. Both orang-utans actively transferred numerous tokens (mostly partner-valuable) to their partner. One of the orang-utans routinely used gestures to request tokens while the other complied with such requests. Although initially the transfers were biased in one direction, they became more balanced towards the end of the study. Indeed, data on the last three series produced evidence of reciprocity both between and within trials. We observed an increase in the number and complexity of exchanges and alternations. This study is the first experimental demonstration of the occurrence of direct transfers of goods based on calculated reciprocity in non-human-primates.
