Ancient DNA Shows the 'American Cheetah' Was Really a Puma Relative

An extinct Pleistocene predator nicknamed the "American cheetah" has turned out to be much more closely related to modern pumas than to true cheetahs, according to a genetic analysis published September 4 in Current Biology. The nickname for Miracinonyx trumani has long suggested a specialized, high-speed predator built like the African cheetah to chase fast prey such as pronghorn, which can sprint nearly 90 kilometers per hour. Pumas, by contrast, are far more flexible hunters that take prey ranging from deer and elk to rodents and raccoons.

Researchers led by Molly Cassatt-Johnstone of the University of California, Santa Cruz, originally set out only to confirm the identity of three roughly 31,000-year-old fossils from Canada's Yukon Territory, which had tentatively been identified as pumas because they were found so far north. "It wasn't until we were able to generate the genetic data that we were able to identify them as American cheetahs," Cassatt-Johnstone said. Ancient DNA from those specimens, plus another M. trumani fossil from Natural Trap Cave in Wyoming, showed the species' closest living relative is the puma, with the two lineages sharing a common ancestor around 2.6 million years ago. M. trumani and true cheetahs split roughly 4.7 million years ago.

The Yukon fossils also expanded the known range of M. trumani, which previously spanned from Florida to the northern plains, further north into Canada. Because the animals lived so far north, likely without pronghorn available as prey, the researchers used nitrogen analysis, a method that measures forms of nitrogen in fossils to reveal what an animal ate, to determine the cats' diet. Wyoming specimens showed nitrogen levels consistent with a terrestrial carnivore that fed on herbivores, but the Yukon specimens had nitrogen levels comparable to marine carnivores such as orcas, suggesting they ate almost exclusively fish.

One of the Yukon fossils was found in a cave that also holds many Pleistocene fish fossils. It remains unknown whether the northern cats caught fish themselves or scavenged carcasses along riverbanks. Larisa DeSantis, a paleoecologist at Vanderbilt University who was not involved in the study, said the adaptability is notable given how dangerous chasing large prey can be for carnivores. Miracinonyx trumani inhabited North American grasslands from roughly 2.5 million to 16,000 years ago.