Assertion: american bison | /r/CapableOf | blacken the plains of north america
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text: That theory is lent weight by subsequent events: the Giant Bison is believed to have evolved into the smaller Bison antiquus, which itself evolved into the even smaller Bison bison, which blackened the plains of North America until it was hunted to extinction by Native Americans and European colonists by the end of the 19th century.