In October, 2010, a worker bulldozing a reservoir outside of Snowmass, Colorado finds some large bones that turn out to be those of a mammoth. A team headed by experts from the Denver Museum of Nature & Science unearth more mammoth bones, as well as many more of mastodon, some representatives of an extinct species of bison, and specimens of other varieties of Ice Age megafauna, dating from 45,000 to 150,000 years ago. The find is a mixed blessing, as the researchers are put in the odd situation of having to rush the excavation of the find of a lifetime.
From the scientists involved (and with the help of some adequate CGI), the viewer receives a crash course in the ecology of Pleistocene North America, the science behind ice ages in general, and the evolution of this particular site over tens of thousands of years--from lake, to bog, to meadow. The team (which includes experts in geology, paleontology, paleobotany, and evolutionary biology) examines several lines of evidence, concluding that the mass grave is probably the result of "liquefaction" from earthquakes sucking heavy beasts into the lake bed. But for all they learn about the site, new questions arise. Why are all the bones those of herbivores, without even any signs of scavenging on the bodies? Where are the predators and scavengers? Where are the saber-toothed cats, short-faced bears, and dire wolves?
And what of the 40,000-year-old mammoth covered in seemingly out-of-place boulders? It reminds at least one of the scientists involved of a known method ancient hunters used to cache large kills at the bottoms of lakes. Additionally, one of these bones has marks on it that don't seem consistent with gnawing or contact with rocks. Could humans have been there, thousands of years before our species is supposed to have discovered this continent? Extraordinary claims require extraordinary evidence... and, frankly, I'm unconvinced. But the hypothesis is intriguing, nonetheless.
NOVA's "Ice Age Death Trap" is yet another quality presentation from PBS.