They belong to the genus Rhombomys, and really ought to be marketed here in pet stores as the "Rambo Gerbil". They'd sell like hotcakes, only they're colonial and live in burrows. They sound a bit like prairie dogs, in a way. The story doesn't address what people might have done to cause a huge rodent population explosion. Like kill off all the local predators for the fur market, or start irrigating desert for grain production? Inquiring minds want to know. At least, this one does.