China’s most mysterious wildcat may not be its own species

2021-06-23

Deep in the alpine meadows of the Tibetan Plateau slinks one of the world’s most mysterious felines. The Chinese mountain cat—with its sky-blue eyes, sandy coat, and unusual lack of markings—is so elusive that it wasn’t photographed in the wild until 2007. For decades, many have considered the stocky-legged feline the only species of cat native to China. But that may be about to change.

A new genetic analysis of more than two dozen Chinese mountain cats concludes that the creature is not its own species, but rather a subspecies of feline that gave rise to several modern wildcats and the domestic cat. That demotion could hamper efforts to save the vulnerable animal, fears Jim Sanderson, a wildlife ecologist with the conservation group Re:wild who snapped that first photo. “The belief is that if it’s not a species, nobody cares.”

The new study began as an attempt to figure out whether China had independently domesticated the housecat. Most scholars believe domestic cats arose in the Middle East about 10,000 years ago. But there was evidence that other domestications could have occurred in Asia thousands of years later. Was the Chinese mountain cat involved?

To find out, Peking University geneticist Shu-Jin Luo traveled to the Tibetan Plateau, where she had mountaineered in college—“a dream come true,” she remembers. Luo and her colleagues trekked the windswept heights looking for Chinese mountain cats to sample. It wasn’t easy. Locals, some of whom hunt the cat for its bushy pelt, call the feline the “grass cat” because it blends in so well with the dry stalks of its surroundings.

That may explain why the researchers never encountered a live specimen. Instead, they got their DNA samples from roadkill, old pelts, and cats in museums and zoos. In what became the largest genetic study of Chinese cats, the scientists collected DNA from 27 Chinese mountain cats, 239 domestic cats, and four Asiatic wildcats—another small feline that ranges across Asia. The team looked at entire nuclear genomes, including Y chromosomes passed down from fathers and mitochondrial DNA passed down from mothers.

The domestication question was easy to settle. All of the Chinese domestic cats were genetically indistinguishable from their comrades across the globe, confirming that all domestic cats originated from the same Middle Eastern ancestor, the team reports today in Science Advances.

But the genetic analysis also led the scientists into a taxonomic minefield. When a French biologist first classified the Chinese mountain cat in 1892, he christened it Felis bieti (after a French missionary), designating it as its own species. That classification largely stood until 2007, when a mitochondrial genetic analysis suggested the Chinese mountain cat was instead a subspecies of the wildcat (F. silvestris). F. bieti became F. sylvestris bieti, joining five other felines—including the Asiatic wildcat (F.s. ornata) and the domestic cat (F.s. catus)—as taxonomically subordinate to the wildcat. Then, in 2017, a team of biologists reversed course after considering the feline’s appearance and geographic range, among other criteria. The Chinese mountain cat was once again its own species, they declared.

“It’s politics, not science. It’s become a sideshow,” says Carlos Driscoll, a geneticist at the research nonprofit Galton Corp. who was involved with both earlier efforts and the new study, but stands by the conclusions of the 2007 paper. To this day, Driscoll says, experts don’t agree on what exactly the Chinese mountain cat is.

Luo’s findings largely support Driscoll’s 2007 study. Her team discovered that the Chinese mountain cat, the Asiatic wildcat, and the domestic cat formed three distinct genetic clusters equidistant from each other—and that all three were much more closely associated with the wildcat than with small felines like Africa’s black-footed cat and the jungle cat, which roams the Middle East and Asia. Together, this suggests the Chinese mountain cat, the Asiatic wildcat, and the direct ancestor of the domestic cat descended from a wildcat ancestor probably about 1.5 million years ago, the researchers conclude.

“It’s a very nice study,” says Claudio Ottoni, a paleogeneticist at the Sapienza University of Rome and an expert on ancient cat DNA. “The genetic signal is pretty clear.”

Still, he contends, the findings only show that the Chinese mountain cat, the Asiatic wildcat, and the domestic cat should have the same taxonomic rank. The genes alone can’t determine whether the cats are all subspecies of the wildcat or all species in their own right, he says.

Sanderson, who also runs the Small Wild Cat Conservation Foundation, prefers the latter option. As part of the 2017 effort that elevated the status of the Chinese mountain cat, he says the feline’s distinctive appearance and relatively ancient origin are reasons enough to make it its own species. “It’s clearly a different kind of animal.”

Sanderson admits he’s motivated by a desire to save the Chinese mountain cat. Estimates put the feline’s numbers at less than 10,000, and it’s listed as “vulnerable” by the International Union for Conservation of Nature. An illegal trade in the cat’s fur, habitat loss and degradation, and the poisoning of one of its main food sources—the mouselike crop pest pika—are major threats. And an influx of people into the Tibetan Plateau since the 1950s has led to a surge of domestic cats—which appear to be interbreeding with the Chinese mountain cat, potentially corrupting its genome.

“We’re living in an age of extinction,” Sanderson says. “The Chinese mountain cat deserves every bit as much attention as the panda.”

Luo agrees, and adds that although the unusual cat may not enjoy as much popularity as her country’s famed bear, people still want to save it. “Even if it’s just a subspecies,” she says, “it still has a lot of value.”

sciencenews.org, 23 June 2021
; https://www.sciencemag.org