Hungry prehistoric hunters, not climate change, drove elephants and wooly mammoths to extinction during the Pleistocene era, new research suggests.
在約一萬年前的更新世，大象和猛犸象從地球上許多地區(qū)大量消失。一項(xiàng)新研究表明，導(dǎo)致這場滅絕的并不是氣候劇變，而是饑餓的史前獵人。
At least 12 kinds of elephants and mammoths used to roam the African, Eurasian, and American continents. Today, only two species of elephants are left in South Asia and sub-Saharan Africa. One theory for this dramatic demise holds that rapid climate shifts at the end of the most recent major ice age, some 10,000 years ago, altered vegetation and broke up habitats, causing the death of those unable to adapt to the new conditions. Another hypothesis blames prehistoric humans, whose improved weapons and hunting techniques allowed them to wipe out whole herds of elephants and mammoths (Science, 8 June 2001, p. 1888).
歷曾經(jīng)至少有12種大象和猛犸象漫游在非洲、美洲和歐亞大陸，但現(xiàn)在只剩下亞洲象和非洲象兩種。有的科學(xué)家認(rèn)為，在約一萬年前的最近一次冰期，地球氣候急劇變化，影響植被、破壞棲息地，大部分大象和猛犸象難以適應(yīng)新的環(huán)境，以至滅絕。另一種假設(shè)則提出，當(dāng)時(shí)的史前人類掌握了更精良的武器和更嫻熟的捕獵技巧，可以獵殺整群的大象和猛犸象，致使其滅絕。
To help resolve the debate, archaeologist Todd Surovell of the University of Wyoming, Laramie, and colleagues tested two assumptions. If humans caused the elephant and mammoth extinctions, Surovell reasoned, the timing of the die-offs in specific regions should match human expansion into those regions. On the contrary, if the extinction of these mammals were due to climate change, elephants and mammoths should remain in regions already colonized by humans and would only begin to die off once climate change occurred.
為了解決這個(gè)爭議，美國懷俄明大學(xué)的考古學(xué)家Todd Surovell及其同事對以上兩種假說進(jìn)行了檢驗(yàn)。Surovell提出，如果主要原因在于人類，那么特定地區(qū)大象和猛犸象的滅絕情況應(yīng)與人類在該地區(qū)的擴(kuò)張一致。相反，如果是氣候?qū)е铝藴缃^，那么在已經(jīng)有人居住的地區(qū)，大象和猛犸象也仍然存在，直到氣候變化來臨。
The team tested both theories by analyzing where and when elephants and mammoths were killed. In all, the study included 41 archaeological sites on five continents. The researchers found that, as humans migrated out of Africa, they left a trail of dead elephants and mammoths in their wake. The creatures disappear from the fossil record of a region once it became colonized by humans. Modern elephants survived in refuges uninviting to humans, such as tropical forests, says Surovell, whose team reports its findings online this week in the Proceedings of the National Academy of Sciences.
為此，研究小組分析了大象和猛犸象被人類捕殺的時(shí)間和地點(diǎn)等情況。他們對5大洲41處考古地點(diǎn)進(jìn)行研究，結(jié)果發(fā)現(xiàn)，人類走出非洲的途中，身后一路留下大象和猛犸象的遺骸。某一地區(qū)一旦有人類居住，這里的大象和猛犸象就開始從化石記錄里消失。Surovell提出，現(xiàn)代大象的祖先是因?yàn)榫幼≡跓釒в炅值热祟愲y以到達(dá)的地方，才得以存留。有關(guān)論文發(fā)表在本周的美國《國家科學(xué)院學(xué)報(bào)》(PNAS)上。
Biologist R. Dale Guthrie of the University of Alaska in Fairbanks largely agrees with the findings, but he says more work is needed to explain why some mammoths seem to have survived in regions colonized by humans and why many modern elephants live in areas easily accessible to humans, such as the African savannah.
阿拉斯加大學(xué)的生物學(xué)家R. Dale Guthrie大體上同意這種看法，但認(rèn)為還需要更多研究來解釋一些現(xiàn)象，如猛犸象為何能在有人居住的地方生存，現(xiàn)代大象為何能生活在人類容易到達(dá)的非洲大草原等地區(qū)。
在約一萬年前的更新世，大象和猛犸象從地球上許多地區(qū)大量消失。一項(xiàng)新研究表明，導(dǎo)致這場滅絕的并不是氣候劇變，而是饑餓的史前獵人。
At least 12 kinds of elephants and mammoths used to roam the African, Eurasian, and American continents. Today, only two species of elephants are left in South Asia and sub-Saharan Africa. One theory for this dramatic demise holds that rapid climate shifts at the end of the most recent major ice age, some 10,000 years ago, altered vegetation and broke up habitats, causing the death of those unable to adapt to the new conditions. Another hypothesis blames prehistoric humans, whose improved weapons and hunting techniques allowed them to wipe out whole herds of elephants and mammoths (Science, 8 June 2001, p. 1888).
歷曾經(jīng)至少有12種大象和猛犸象漫游在非洲、美洲和歐亞大陸，但現(xiàn)在只剩下亞洲象和非洲象兩種。有的科學(xué)家認(rèn)為，在約一萬年前的最近一次冰期，地球氣候急劇變化，影響植被、破壞棲息地，大部分大象和猛犸象難以適應(yīng)新的環(huán)境，以至滅絕。另一種假設(shè)則提出，當(dāng)時(shí)的史前人類掌握了更精良的武器和更嫻熟的捕獵技巧，可以獵殺整群的大象和猛犸象，致使其滅絕。
To help resolve the debate, archaeologist Todd Surovell of the University of Wyoming, Laramie, and colleagues tested two assumptions. If humans caused the elephant and mammoth extinctions, Surovell reasoned, the timing of the die-offs in specific regions should match human expansion into those regions. On the contrary, if the extinction of these mammals were due to climate change, elephants and mammoths should remain in regions already colonized by humans and would only begin to die off once climate change occurred.
為了解決這個(gè)爭議，美國懷俄明大學(xué)的考古學(xué)家Todd Surovell及其同事對以上兩種假說進(jìn)行了檢驗(yàn)。Surovell提出，如果主要原因在于人類，那么特定地區(qū)大象和猛犸象的滅絕情況應(yīng)與人類在該地區(qū)的擴(kuò)張一致。相反，如果是氣候?qū)е铝藴缃^，那么在已經(jīng)有人居住的地區(qū)，大象和猛犸象也仍然存在，直到氣候變化來臨。
The team tested both theories by analyzing where and when elephants and mammoths were killed. In all, the study included 41 archaeological sites on five continents. The researchers found that, as humans migrated out of Africa, they left a trail of dead elephants and mammoths in their wake. The creatures disappear from the fossil record of a region once it became colonized by humans. Modern elephants survived in refuges uninviting to humans, such as tropical forests, says Surovell, whose team reports its findings online this week in the Proceedings of the National Academy of Sciences.
為此，研究小組分析了大象和猛犸象被人類捕殺的時(shí)間和地點(diǎn)等情況。他們對5大洲41處考古地點(diǎn)進(jìn)行研究，結(jié)果發(fā)現(xiàn)，人類走出非洲的途中，身后一路留下大象和猛犸象的遺骸。某一地區(qū)一旦有人類居住，這里的大象和猛犸象就開始從化石記錄里消失。Surovell提出，現(xiàn)代大象的祖先是因?yàn)榫幼≡跓釒в炅值热祟愲y以到達(dá)的地方，才得以存留。有關(guān)論文發(fā)表在本周的美國《國家科學(xué)院學(xué)報(bào)》(PNAS)上。
Biologist R. Dale Guthrie of the University of Alaska in Fairbanks largely agrees with the findings, but he says more work is needed to explain why some mammoths seem to have survived in regions colonized by humans and why many modern elephants live in areas easily accessible to humans, such as the African savannah.
阿拉斯加大學(xué)的生物學(xué)家R. Dale Guthrie大體上同意這種看法，但認(rèn)為還需要更多研究來解釋一些現(xiàn)象，如猛犸象為何能在有人居住的地方生存，現(xiàn)代大象為何能生活在人類容易到達(dá)的非洲大草原等地區(qū)。