America’s Pronghorns are survivor of a mass extinction.
Where cars now drive along congested roads in the heart of modern Los Angeles, sabre-toothed cats once roamed. They stalked prey that ranged from hoofed mammals to creatures resembling elephants. The ferocious cats competed with dire wolves, American lions and short-faced bears.
During the Pleistocene, the geological period that began just over 2.5 million years ago, North America experienced a series of ice ages. During these freezes and thaws, giant mammals thrived in the woodlands and savannahs of Southern California. Primitive cheetahs chased antelope-like pronghorns over miles of grasslands, while mastodons roamed in dense herds.
But suddenly, around 11,000 years ago, almost all of these species died. Mammoths, giant sloths and camels all disappeared completely from the Americas. Only one large plant-eater remained, nearly unchanged since it first began racing through the south-west 30,000 years ago: the pronghorn.
Nobody is really sure what caused the extinction event. It has variously been blamed on fluctuating temperatures and climates, the encroachment of man, invasive plants or new bacteria, or all of the above.
But perhaps the bigger question is, why did some species survive while so many died out? In particular, why was the pronghorn able to outlast almost every Ice Age herbivore and persist into the present day — with pretty much the same build and look as it did in prehistory, to boot?
It is not just an academic question. Figuring out how the pronghorn survived the mass extinction could help us understand the mass extinction that is now underway, and offer tips on how to rescue today’s threatened species.