一項(xiàng)新的研究證明：當(dāng)猩猩還很年輕的時(shí)候,，他們就開始形成自己對(duì)外界的看法——特別是,，在什么情況下，如何使用特定的工具,。這項(xiàng)研究指出,，猩猩的文化傳統(tǒng)也許與人類沒有太大不同。
和人類一樣,，猩猩的行為習(xí)慣也隨著地域的不同而變換多樣,。例如，一個(gè)區(qū)域的猩猩使用工具,，另一個(gè)區(qū)域的猩猩就不用工具,。在印尼西部的蘇門答臘島上,，來自蘇門答臘艾拉斯河西部沼澤區(qū)六七歲的猩猩會(huì)使用木棍去尋找蜂蜜。但是,，研究人員從來沒有發(fā)現(xiàn)河?xùn)|岸沿海地區(qū)的猩猩使用這種方式采蜜,。
許多專家稱，猩猩通過觀察人類采蜜學(xué)會(huì)了這種采蜜的方法,。美國(guó)耶魯大學(xué)的人類學(xué)家David Watts說,，即使觀察最仔細(xì)的研究人員也很難證明這一點(diǎn)。他還表示,，野生猩猩總是能和它們周邊的環(huán)境相適應(yīng),。環(huán)境對(duì)他們行為的影響遠(yuǎn)遠(yuǎn)大于社會(huì)學(xué)習(xí)對(duì)它們的影響。
科學(xué)家被允許測(cè)試猩猩的社會(huì)學(xué)習(xí)能力在多大程度上影響它們的行為,。采伐森林使得艾拉斯河兩岸的許多猩猩成為孤兒,，它們被關(guān)在蘇門答臘北部的Batu Mbelin收容所。最初,，它們被檢疫并隔離了一段時(shí)間，然后被放逐到大的種群中,。
瑞士蘇黎世大學(xué)人類學(xué)研究所暨博物館心理學(xué)家Thibaud Gruber和他的同事開始研究Batu Mbelin被隔離的猩猩,。研究團(tuán)隊(duì)給猩猩設(shè)置了兩個(gè)以木棍為基礎(chǔ)的挑戰(zhàn)：將食物耙進(jìn)它們的籠子和用木棍采食蜂蜜。
來自兩岸的猩猩都很快將食物耙進(jìn)了籠子,。Gruber說：“這說明所有猩猩都能明白地將木棍作為工具,。”但是，相比之下,，來自西岸的13只猩猩中,，有9只知道用木棍取食蜂蜜；來自東岸的10只猩猩中只有2只這樣做,。Gruber的團(tuán)隊(duì)將報(bào)告發(fā)表在本月的《當(dāng)代生物學(xué)》上,。Gruber補(bǔ)充道，來自西岸的猩猩平均年齡只有4歲——如果它們生存在郊外的話,，這個(gè)年齡取食蜂蜜還太年輕,。這就說明具體使用工具的方法來自觀察別人。
美國(guó)雅典市佐治亞大學(xué)的氣象學(xué)家Dorothy Fragaszy說：“猩猩可能具備Gruber形容的想法,，但是這種解釋似乎不那么合乎情理,。”Fragaszy提示Gruber只引用一項(xiàng)研究來討論猩猩在野外使用木棍的情況。“我可以說,，當(dāng)它們離開野外環(huán)境后,，這些猩猩孤兒在某地學(xué)到了使用工具的一般過程。”
Gruber擔(dān)心有一天這樣的研究只能在蘇門答臘北部展開,。使用工具的猩猩所居住的森林正在被大火燒毀,，他說：“它們正在失去家園,，同時(shí)也許意味著它們?cè)谑プ约旱奶煨浴?rdquo;(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.
