A muskox (Ovibos moschatus), photographed in Alaska. From Flickr user drurydrama.
Of all the mass extinctions that have occurred during earth's history, among the most hotly debated is the one which wiped out mammoths, saber-toothed cats, giant ground sloths, and the other peculiar members of the Pleistocene megafauna around 12,000 years ago. It was not the most severe mass extinction, not by a long shot, but unlike the end-Cretaceous catastrophe 65 million years ago there is no single "smoking gun" that can account for the pattern of extinction. Instead the Pleistocene mass extinction remains a very mysterious event, but by looking at the natural history of one of the event's survivors scientists have been able to get a better idea about how one of the suspected extinction triggers affected prehistoric mammals.
Today's populations of muskox (Ovibos moschatus) are remnants of the Pleistocene herds which were once spread all around the Arctic Circle. The shaggy bovids are survivors of the events which wiped out so many other large mammals, but this does not mean that they were immune to ecological changes that may have played a pivotal role in the extinction. As illustrated by a new paper in the journal PNAS, the changing climate had a major influence on muskox populations, and by looking at what happened to them it may be possible to understand the fate of some of their extinct contemporaries.