美国科学60秒 SSS 2015-02-16

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It has long been thought that mammoths and mastodons rambled² over North American subartic grounds between 75,000 and 10,000 years ago, and were made extinct by hungry new arrivals on the scene, human beings. But new evidence indicates mastodons probably round the region as  far back as 120,000 years ago, and they were gone before the first people showed up.” For at least the story with the mastodons we now know that in what we called the beringia, Alaska part of Uncon over into northeast of Asia, they were wiped out in those areas for things they had nothing to do with humans, because they were died out before there were humans there. Park. DragonMiler, the curator of worlds science of University of Alaska museum of the north. Humans could not have been part of the story, and that’s pretty interesting. The research in proceeding⁴ of National Academy of Science, Dragon Miler and Co-author were led to the conclusion after colleague at Ucon paleontology program in Canada, decide to re day nearly 40000 specimen⁵, Because American mastodon are often mistaken for their much hairier wooly⁶ mammoth¹ cousins, who hung around the area later. A mammoth and a mastodon can be immediately distinguished⁷ on the basis of their teeth, their big cheek teeth. The surface of the mammoth tooth looks like a washboard, prefect for grinding grasses the grew during last ice age, the mastodon tooth has much lumpier, bumpier⁸ cusps, ideal for chewing twigs⁹ and leaves, people on the past when they found the teeth and bonds, they put glue and other kind of strange things on them, that glue can actually mess dates, it give a wrong date, and in fact give you a date too young, the new date corroborate¹⁰ what mastodon teeth show. They ambled³ over the Beringia. When the region were warmer and forested, long before mammoth and earlier than human, So if human didn’t wipe out mastodon, what did, that mystery remains for scientist to think their teeth into

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