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Megabeasts' Sudden Death

Season 36, Episode 7 of 17

What killed the mastodons? Thirteen thousand years ago, these tusked beasts disappeared from North America, along with some 35 genera of oversized mammals, including woolly mammoths, saber-tooth cats and even camels. For four decades, debate has raged over the cause of this extinction. In LAST EXTINCTION, NOVA presents an exclusive investigation of a startling and controversial new hypothesis which suggests that a cosmic collision could be the culprit. If a comet exploded in the upper atmosphere over the Great Lakes, the blast would have vaporized everything within a 100-mile radius. From coast to coast, wildfires would have raged and turned forests into cinder. Now, at more than two dozen sites across the continent, a multidisciplinary team finds evidence that just such a fire once ravaged North America. But other scholars argue that ancient hunters armed with a distinctive, lethal stone weapon -- the Clovis spear point -- drove the giant beasts into oblivion. Still others believe the unstable climate at the end of the Ice Age was responsible. Now the dramatic new evidence of a cosmic explosion suggests a third possibility -- that mammoths and mastodons already stressed out by human "overkill" and climate change may have received a fiery coup-de-grace as devastation swept across the continent.

Previously Aired

Day
Time
Channel
2/23/2010
8 p.m.
2/24/2010
1 a.m.
2/26/2010
11 p.m.
4/5/2011
8 p.m.
2/21/2012
8 p.m.
2/25/2012
3 p.m.
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