科学美国人60秒:远古人类为生存致鸟类灭绝-托福听力下载

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　　科学美国人60秒中英文翻译：远古人类为生存致鸟类灭绝

　　科学美国人60秒英文文本

　　Extinction. When species go bye-bye forever, we usually blame things like climate change, volcanic eruption or asteroid impact.

　　But for the giant flightless birds that once roamed the Australian outback, it was an omelet station what did 'em in.

　　A new study finds evidence that about 47,000 years ago, humans helped to wipe out this avian leviathan by collecting and cooking its eggs.

　　The study is in the journal Nature Communications.

　　Before humans swept over the land down under, animals of enormous proportions were not uncommon.

　　A two-ton wombat, a thousand-pound kangaroo, and a 500-pound bird now known as Genyornis newtoni were spread across the continent.

　　But most of these so-called megafauna disappeared once humans hit the scene.

　　Coincidence? Well, it could be.

　　Which is why researchers set out to look for proof that human predation played a role in the demise of Genyornis.

　　They collected eggshells from hundreds of sites around the country.

　　And they found that the shell fragments exhibited scorch marks that suggested that the eggs had been purposefully cooked over an open flame.

　　Marks that were not consistent with the eggs getting, say, burned up in a wildfire.

　　Three different dating methods put the eggs'age in the correct era, and thus place the smoking gun—or in this case, firepit—directly in the hands of hungry humans.

　　Which suggests that our ancestral appetite for over-easy compromised the fitness of this species.

　　Ultimately leading to its egg-stinction.

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