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Saber-tooth died out, but another big cat survived.
The puma1 may have been more able to adapt because its diet is more varied2 and includes small prey3. The grizzly4 bear also lived through the post Ice Age changes and now thrives in North America. Once again, a varied diet of meat and plants made it a versatile5 survivor6.
The moose is now the largest browser7 on the continent. During the last Ice Age, moose were restricted to the far north, but after the ice melted, they spread south. They took the place of mastodons and the larger stag-moose, both of which became extinct.
Bison, too, were to benefit from the post Ice Age changes. They managed to survive the draught8, eventually expanding in number to replace the horse as dominant9 grazer. As ruminants with multi-chambered stomachs, bison can extract more nutrients10 from grass and this may help explain why they survived when other grazers such as the wild horses did not.
While all these creatures were adapting to their changing landscape, another animal was just beginning to make North America its home. It’s thought the dog arrived with early people and its descendents are still with us today. The Carolina dog lives in the woods of South Carolina. Like most primitive12 dogs, it makes its den11 in the ground or in hollow tree trunks. The Carolina dog is often called the American dingo. It does look like its Australian relative, but links between the two may go deeper than that. Genetic13 analysis of the Carolina dogs suggests they are closely related to primitive wild dogs like the dingo.
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1 puma | |
美洲豹 | |
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2 varied | |
adj.多样的,多变化的 | |
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3 prey | |
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨 | |
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4 grizzly | |
adj.略为灰色的,呈灰色的;n.灰色大熊 | |
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5 versatile | |
adj.通用的,万用的;多才多艺的,多方面的 | |
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6 survivor | |
n.生存者,残存者,幸存者 | |
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7 browser | |
n.浏览者 | |
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8 draught | |
n.拉,牵引,拖;一网(饮,吸,阵);顿服药量,通风;v.起草,设计 | |
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9 dominant | |
adj.支配的,统治的;占优势的;显性的;n.主因,要素,主要的人(或物);显性基因 | |
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10 nutrients | |
n.(食品或化学品)营养物,营养品( nutrient的名词复数 ) | |
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11 den | |
n.兽穴;秘密地方;安静的小房间,私室 | |
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12 primitive | |
adj.原始的;简单的;n.原(始)人,原始事物 | |
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13 genetic | |
adj.遗传的,遗传学的 | |
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