STL Science Center

STL Science Center

14 October 2011

The Arc Told Us

©Daniel Reed
Minus the "L" that's almost a clever joke for this coming week. This week, the third week of Cenozoic mammals month, our discussions will concern the ursine denizens of the North American Ice Ages. Moving about the continent from about 3 million years ago to approximately 11,000 years ago, Arctodus, more commonly referred to as Short Faced Bears, were truly enormous. There are two species in the genus Arctodus. These species are Arctodus simus and Arctodus pristinus. Bears existed in South America and Europe as well at this time, but were of different genera than Arctodus such as Arctotherium and Plionarctos. Arctodus was found solely in North America and had become quite widespread by the Kansan age; approximately 800,000 years ago.

What Arctodus did as a genus prior to that time, since it has been noted to have diverged from ancestors 3 million years ago, is not well documented. Of the two species, A. simus lived in the northern half of the continent and some of the south with fossils being found in Alaska, California, and Mississippi while A. pristinus diverged in evolution to adapt to life in the southern part of the continent including Texas and even Mexico with rather large concentrations found in Florida.

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