Almost everyone agrees that the North American Pleistocene megafauna, the large animals of the last ice age, pretty much died out around 11,000 years ago, give or take a few thousand. Arguments about causes of extinction of North American horses, camels, elephants, ground sloths, and many other animals have raged furiously for many years. One possibly explanation advanced among the many arguments about causes has been disease sweeping across the continent as the ice retreated.
Recently, it's been recognized that many fossils of large mammals
show the effects of tuberculosis. But anyone who would claim this as evidence of
disease-caused extinction would need to explain a few things, for the disease was
widely present for many thousands of years before the megafauna disappeared. So did it
play any part? Possibly. Like many diseases that we learn to live with under normal
conditions, tuberculosis is apt to become deadly when the infected are stressed by the
environment. With the climate changing rapidly and hunting man appearing, there was
plenty going on to stress even a 4-ton mammoth.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.