Scientists think they’ve helped settle a debate over one of the most endangered (and cutest) animals around: the red panda. New genetic evidence suggests there are really two different species of red panda, each with a unique evolutionary history.
Red pandas (Ailurus fulgens) are the only mammals of their kind, though they are closely related to raccoons, skunks, and weasels. They’re infamously much less related to giant pandas than their shared name and love of bamboo implies, with the giant pandas being part of the bear family. Scientists have long known that there are two distinct groups of red pandas, typically thought to be separated by the Nujiang River that cuts through Burma, China, and Thailand. These groups have been known as the Himalyan red panda (A. fulgens fulgens) and the Chinese red panda respectively (A. fulgens styani).
The two populations have historically been considered subspecies, meaning they’re physically different enough that you can tell them apart and live far enough away that they rarely breed with each other. Subspecies are still typically capable of having viable offspring when they do mingle, though, while animals of differing species are more genetically distinct from one another and usually have sterile offspring if they are able to mate (as with anything in life, though, there can be exceptions).
The Himalayan and Chinese red panda certainly appear different if you’re looking hard enough, with Himalayan red pandas having faces with more whitish fur, while Chinese red pandas have tails that are more intensely red and pale tail rings that are more white. The differences between the two groups, some scientists have argued, indicate that they aren’t just subspecies, but wholly separate species. But up until recently, the authors of this study say, we haven’t really had the tools needed to look closely at the genetics of both groups.
In their new paper, published Wednesday in Science Advances, the researchers reconstructed and analyzed DNA taken from blood, muscle, and skin samples of 65 red pandas in the wild, belonging to seven populations in total. They found “substantial genetic divergence between the two species, providing the first genomic evidence of species differentiation.”
Among other things, the team found evidence that the groups have taken different evolutionary paths to get where they are today—differences that could have a real impact on their chances of survival.
Himalayan red pandas, for instance, may have experienced three sharp reductions in their numbers over time, a phenomenon known as a bottleneck, while only having one relatively small population boom. Chinese red pandas, on the other hand, seem to have had fewer bottlenecks and a longer period of population growth. As a result, Chinese red pandas are more genetically diverse, while Himalayan red pandas are more at risk of the harmful mutations that can plague populations with very low diversity.
The team also found evidence that the geographical divide between the two groups isn’t the Nujiang River after all, since panda populations living on either side of the river seemed genetically similar (other studies looking at the skulls of red pandas have suggested the same). Instead, they theorize that the actual barrier keeping those two groups apart is the Yalu Zangbu River, which largely runs through Tibet and is north of the Himalayas. But more research will be needed to confirm that theory.
The authors hope their findings will better guide and motivate conservation efforts for the red pandas. Overall, there are only thought to be 10,000 or so red pandas in the world, but the situation may be even worse for the Himalayan red panda.
“In particular, the Himalayan red panda population spans southern Tibet of China, Nepal, India, and Bhutan, which needs urgent transboundary international cooperation to protect this decreasing species,” the authors wrote.