20 December 2015

20. Waco Mammoth

Columbian Mammoths from the Waco Mammoth Site
Larry D. Moore, Wikimedia
Location: Texas, USA
Age: Pleistocene (68,000-53,000 years ago)

Snowmass is known for its mastodons, proboscideans - members of the same order of mammals as elephants - that were early stars of the North American fossil record.  In time, though, their status in the popular imagination as iconic megafauna would be usurped by another type of proboscidean: mammoths.  Mammoths are much closer relatives of elephants (they are, in fact, more closely related to Asian elephants than are African elephants) and while the most famous of them is Mammuthus primigenius (the woolly mammoth), the most widespread species in North America is the Columbian mammoth, Mammuthus columbi.  They are well-represented at several sites across the continent and have figured prominently in the debate over whether human activity or climate change played a larger role in the extinction of megafauna at the close of the Pleistocene.  In at least one case, though, the death of several mammoths can be clearly attributed to natural causes.  In what is now Waco, Texas, a flash flood 68,000 years ago killed and buried a herd of Columbian mammoths, making the site, like Ashfall, a snapshot of a moment in time.  Unusually, many of the individuals at the Waco Mammoth Site are juveniles, leading to the suggestion that the group killed in the flood was a nursery herd.  Other layers at the site preserve younger, less fatal floods, that preserved more mammoths and, among other things, remains of another icon of the Ice Ages: the saber-toothed cat Smilodon.  As with all mammalian predators, Smilodon tends to be much less common than its prey at most localities, and were this true everywhere, it might remain a somewhat enigmatic animal.  Fortunately, just as the Waco Mammoth Site preserves huge concentrations of herbivores, other sites have done the same for the animals that preyed upon them.

Visit: This July, President Obama designated the Waco Mammoth Site a national monument, preserving the locality - and guaranteeing its visitability - in perpetuity.
Fossils: To the best of my knowledge, all of the fossils from Waco remain on-site.
Is there a relevant book full of gorgeous fossil photos that I can gift to a paleontologically-minded friend?: Not that I'm aware of.

This post is part of my 2015 Paleontology Advent Calendar, a series of vignettes on lagerstätten - sites of exceptional fossil preservation - that document changes in climate and environments through the Cenozoic.  You can see the other posts here.

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