一项新的研究证明：当猩猩还很年轻的时候，他们就开始形成自己对外界的看法——特别是，在什么情况下，如何使用特定的工具。这项研究指出，猩猩的文化传统也许与人类没有太大不同。
和人类一样，猩猩的行为习惯也随着地域的不同而变换多样。例如，一个区域的猩猩使用工具，另一个区域的猩猩就不用工具。在印尼西部的苏门答腊岛上，来自苏门答腊艾拉斯河西部沼泽区六七岁的猩猩会使用木棍去寻找蜂蜜。但是，研究人员从来没有发现河东岸沿海地区的猩猩使用这种方式采蜜。
许多专家称，猩猩通过观察人类采蜜学会了这种采蜜的方法。美国耶鲁大学的人类学家David Watts说，即使观察最仔细的研究人员也很难证明这一点。他还表示，野生猩猩总是能和它们周边的环境相适应。环境对他们行为的影响远远大于社会学习对它们的影响。
科学家被允许测试猩猩的社会学习能力在多大程度上影响它们的行为。采伐森林使得艾拉斯河两岸的许多猩猩成为孤儿，它们被关在苏门答腊北部的Batu Mbelin收容所。最初，它们被检疫并隔离了一段时间，然后被放逐到大的种群中。
瑞士苏黎世大学人类学研究所暨博物馆心理学家Thibaud Gruber和他的同事开始研究Batu Mbelin被隔离的猩猩。研究团队给猩猩设置了两个以木棍为基础的挑战：将食物耙进它们的笼子和用木棍采食蜂蜜。
来自两岸的猩猩都很快将食物耙进了笼子。Gruber说：“这说明所有猩猩都能明白地将木棍作为工具。”但是，相比之下，来自西岸的13只猩猩中，有9只知道用木棍取食蜂蜜；来自东岸的10只猩猩中只有2只这样做。Gruber的团队将报告发表在本月的《当代生物学》上。Gruber补充道，来自西岸的猩猩平均年龄只有4岁——如果它们生存在郊外的话，这个年龄取食蜂蜜还太年轻。这就说明具体使用工具的方法来自观察别人。
美国雅典市佐治亚大学的气象学家Dorothy Fragaszy说：“猩猩可能具备Gruber形容的想法，但是这种解释似乎不那么合乎情理。”Fragaszy提示Gruber只引用一项研究来讨论猩猩在野外使用木棍的情况。“我可以说，当它们离开野外环境后，这些猩猩孤儿在某地学到了使用工具的一般过程。”
Gruber担心有一天这样的研究只能在苏门答腊北部展开。使用工具的猩猩所居住的森林正在被大火烧毁，他说：“它们正在失去家园，同时也许意味着它们在失去自己的天性。”(生物谷Bioon.com)
DOI:10.1016/j.cub.2012.09.041
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Sumatran Orangutans Differ in Their Cultural Knowledge but Not in Their Cognitive Abilities
Thibaud Gruber, Ian Singleton, Carel van Schaik
Animal cultures are controversial [1,2] because the method used to isolate culture in animals aims at excluding genetic and environmental influences rather than demonstrating social learning [3,4]. Here, we analyzed these factors in parallel in captivity to determine their influences on tool use. We exposed Sumatran orangutan (Pongo abelii) orphans from tool-using and non-tool-using regions (western swamps and eastern Langkat, respectively) that differed in both genetic [5] and cultural [6] backgrounds to a raking task and a honey-dipping task [7,8] to assess their understanding of stick use. Orangutans from both regions were equally successful in raking; however, swamp orangutans were more successful than Langkat orangutans in honey dipping, where previously acquired knowledge was required. A larger analysis suggested that the Alas River could constitute a geographical barrier to the spread of this cultural trait [9]. Finally, honey-dipping individuals were on average less than 4 years old, but this behavior is not observed in the wild before 6 years of age. Our results suggest first that genetic differences between wild Sumatran populations cannot explain their differences in stick use; however, their performances in honey dipping support a cultural differentiation in stick knowledge. Second, the results suggest that the honey-dippers were too young when arriving at the quarantine center to have possibly mastered the behavior in the wild individually [10], suggesting that they arrived with preestablished mental representations of stick use or, simply put, cultural ideas.
