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🎁 中英文稿:
Animals that live in the city are usually less wary of humans than their rural counterparts. Most people think the boldness comes from experience: since the majority of humans are rather harmless, the critters learn to go about their business without fear. But the truth turns out to be far more interesting, at least for Australian swans. Turns out the city birds are genetically different from their country counterparts.
與城市動物相比,生活在農村的動物更易懼怕人類。多數人認為勇敢源於經驗:由於大部分人類不會傷害動物,因此動物們可以無所畏懼的從事自己的活動。但是對於澳大利亞的天鵝來說,結果更為有趣。結果表明,城市天鵝和農村的天鵝基因不同。
Australian researchers looked at two groups of swans. One population lived on a pond in the center of Melbourne. The second hung out just 30 kilometers away in a more bucolic setting, surrounded by far fewer humans. The researchers measured what they call each bird’s “flight initiation distance”: basically, how close could a human get before the swan would fly away?
澳大利亞的研究人員調查了兩組天鵝。其中一組生活在墨爾本市中心的池塘裡。而第二組則生活在30公里外,人煙稀少的鄉村景色中。研究人員測量了每只天鵝的“飛行起始距離”:即,在天鵝起飛時,人類可靠近的距離。
“We found that the flight initiation distance for the swans at the urban environment was only 13 meters, and on average at the non-urban environment it was 96 meters. So that’s like an 83 meter difference, a really big difference in how wary these swans are at the two habitats.” Victoria University ecologist Wouter van Dongen.
“我們發現,在城市生活的天鵝其飛行起始距離只有13米,而在非城市環境中天鵝的平均飛行起始距離為96米。這83米的差距也揭示了這些天鵝對兩處不同棲息地謹慎程度。”瑞士維多利亞大學的生態學家Wouter van Dongen說到。
The researchers also took blood samples from some of the swans to analyze their DNA. And almost 90 percent of urban swans had the same variant of a gene for dopamine transport, while just 60 percent of rural birds had that version. And those swans were less wary of humans than were the swans with the rarer genotypes.
研究人員也從天鵝的身上採集了血液樣本分析其DNA。其中,幾乎90%的城市天鵝有多巴胺轉運體變體,而農村天鵝此資料僅為60%。擁有此變體的天鵝更不懼怕人類。
Dopamine influences a lot of brain function, so the gene variation could be behind the difference in swan attitudes. The study is in the journal BMC Evolutionary Biology.