ABSTRACT
Humans colonized North America as a late part of a Siberian megafauna, members of which had existed in Alaska for hundreds of thousands of years. With megafaunal collapse, expanding populations of Siberian colonizers mixed with expanding populations of a few, eurytopic American species to form the new, Holocene American fauna. Humans entered lower North America along with grizzly bears, moose, caribou, and glutton. The wapiti and extant Bison bison are probably both recent Siberians. Another Siberian species that expanded with megafaunal extinction is the timber wolf, which may well have colonized along glacial margins in late glacial times. Human colonization was part of a larger faunal event that shaped today's impoverished, almost certainly poorly adapted fauna of North America. That predation on America's megafauna was historically quite heavy is indicated by several factors: the diversity of predators was high, and they were individually much larger than their Eurasian or African counterparts.
