Mastodons Made an Early Exit from the North

Mastodons and mammoths, two mighty elephant species, roamed North American for millions of years before humans got here. But mastodon fossils in the Arctic and sub-Arctic have presented a problem for paleontologists. These fossils had been dated to about 20,000 years ago, a period at the height of the last Ice Age, when the Arctic was locked in cold, and the ice-free areas were a steppe-tundra grassland. But unlike mammoths, mastodons don't graze on grass - they're adapted to browsing forest and shrubland. So what were these animals doing in such an unsuitable environment? Dr. Grant Zazula, the Yukon Government Paleontologist, and his colleagues, re-dated dozens of mastodon fossils and solved this problem. The fossils turn out to be much older than previously thought - probably by many tens of thousands of years. This suggests that mastodons were only in the North in the warm interglacial period between the Ice Ages - and further suggests that humans didn't wipe them out in the North.