Thursday, July 10, 2008

Milwaukee woolly mammoth

The Milwaukee Public Museum has unveiled the most intact woolly mammoth skeleton so far discovered in North America. The skeleton is only missing a rib, some toes, and a few tail vertebrae. A few of the frozen mammoths unearthed in Siberia have more complete skeletons than that, but they generally had better preservation conditions than those in North America.

Besides being an excellent skeleton, the mammoth shows what might be butcher marks on some bones. This would make the skeleton doubly important because it has been dated at 14,500 years old. That means it died over a thousand years earlier than an other signs of human habitation in that area. Recently, some well dated discoveries have pushed back the date when the first humans arrived in the Americas. Those are mostly limited to the coasts or are far to the south of Wisconsin.

Earlier dates complicate sorting out the relationship between human arrival and the extinction of mammoths and other Ice Age megafauna in the New World. It would mean that humans lived with the mammoths and hunted them for thousands of years before the mammoths went extinct. The usual model of hunting extinction has the hunters crossing the continent in a few hundred years, causing a wave of extinctions. A period of co-existence also causes problems for the idea that the hunters or their dogs might have brought new diseases from Asia that wiped out the mammoths. That model demanded an even quicker extinction wave after first contact.

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