The disappearance of megafauna in America—mammoths, saber-toothed cats, giant sloths, among others—happened relatively soon after the arrival of human beings, about 13,000 years ago.
美洲巨型动物的消失——猛犸象、剑齿猫、巨型树懒等等——发生在人类出现后不久，大约在一万三千年前。
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We evolved to be wary of saber-toothed tigers and blizzards, but not of climate change - and maybe that's also why we in the news media tend to cover weather but not climate.
So in 2005 the scientists sent the skull to a technician, who spent three years removing the rock from around the fossil—finally revealing a saber-toothed, squirrel-like creature.