A fossilized jaw of an ancient Arctic fox is lending credence to the theory that many of the distinctive creatures of the ice age might have originated on the Tibetan plateau.
The paper, in the Proceedings of the Royal Society B, describes the fossil of an extinct fox species, which would have been slightly larger than today’s arctic fox. The shape and sharpness of the fossilized teeth led researchers to the conclusion that this ancient fox was a hypercarnivore—an animal that only eats meat.
From National Geographic:
Eating mostly meat makes sense for polar animals, in part because of the taxing demands of living in such icy cold environments and the scarcity of other food sources, Tseng said. That's likely why, in addition to the arctic fox, other northern carnivores, such as polar bears and gray wolves, are highly predatory.
The ancient fox (Vulpes qiuzhudingi) lived between 5.08 million and 3.6 million years ago, when the poles were a lot warmer than they are today. The Tibetan plateau (which the paper calls the Earth's "third pole") would have still been fairly frigid, allowing cold-weather animals like the fox to thrive, even before the ice age started. When global temperatures started dropping, the cold-loving animals of the plateau, including the fox and the ancestors of wooly rhinoceroses and snow leopards, would have headed north, eventually ending up at the poles.
Whether the ancient fox is actually a direct ancestor of our modern Arctic foxes is still up for debate. Convergent evolution has been known to happen. But this new find does lend a lot of weight to the idea that at least some ice age creatures got their start in Tibet.