Ancient DNA Reveals the 'American Cheetah' Was Actually an Arctic Puma Relative

The animal known for more than a century as the American cheetah was not a cheetah at all, according to ancient-DNA analysis published this week that instead identifies it as an unusually adaptable relative of the mountain lion, one whose northernmost populations survived largely on salmon rather than the fleet-footed prey its name implies.

The study, led by researchers in the Paleogenomics Lab at the University of California, Santa Cruz, examined nuclear genomes and chemical signatures preserved in fossils of Miracinonyx trumani recovered from sites spanning roughly 20 degrees of latitude, from Wyoming and Florida north to the Yukon's Bluefish Caves and Upper Quartz Creek. The findings appear in Current Biology, and were detailed in a release from UC Santa Cruz.

A Genome Rewrites a Family Tree

Miracinonyx trumani was first described in 1969 from a skull found in Nevada's Crypt Cave, and its slender limbs and enlarged nasal passages — features associated in living cats with high-speed pursuit — led generations of paleontologists to treat it as North America's own cheetah, a close cousin of the African species. That resemblance also underpinned a well-known idea in evolutionary biology, the "ghosts of predators past" hypothesis, which credits the pronghorn's extraordinary sprinting speed to millennia of being chased by a cheetah-like predator that no longer exists.

The new genetic evidence complicates that story. According to the paper and the Cell Press announcement accompanying it, M. trumani shares a common ancestor with living cheetahs roughly 4.7 million years ago, but its closest living relative is the puma, from which it diverged only about 2.6 million years ago. Its greyhound-like build, in other words, appears to be a case of convergent evolution — a body plan that arose independently, twice, in unrelated lineages chasing similarly fast prey, rather than a shared inheritance.

The Numbers

The fossils analyzed date to between 23,000 and 31,000 years old. A typical adult weighed around 150 pounds, stood roughly three feet at the shoulder and measured about eight feet from nose to tail, according to reconstructions reported by Sci.News. Stable-isotope measurements — chemical tracers in bone and tooth collagen that record an animal's historical diet — showed a sharp divide by geography: cats from Wyoming and Florida ate land mammals typical of open grassland, while those recovered in the Arctic Yukon carried an isotopic signature consistent with eating fish, very likely anadromous species such as salmon that migrate up rivers to spawn.

How the Case Was Made

Researchers sequenced nuclear paleogenomes — the genetic material recovered from the cell nucleus, which carries far more information than the mitochondrial DNA used in many earlier ancient-DNA studies — from multiple specimens, including three new ones from Yukon Territory that extended the species' known range substantially northward. Molly Cassatt-Johnstone, a doctoral candidate in the UC Santa Cruz lab and the study's lead author, said the genome also carried a signature of physiological adaptation to Arctic conditions.

"These cats were remarkably flexible, much like pumas are across their range today. We found loss-of-function mutations in certain genes that regulate circadian rhythms, suggesting they may have adapted to the extreme light cycles of summers and winters in northern latitudes," Cassatt-Johnstone said.

Matthew Wooller, a researcher at the University of Alaska Fairbanks who worked on the isotope analysis, said the range and dietary split were striking for a single species. "This species of carnivore has this massive range, all the way from the Arctic to the Lower 48," he said. "They're demonstrating uber-specialization at two ends of their range, while also feeding on two completely different food sources."

Who Is Affected

The revision matters most directly to paleontologists and evolutionary biologists who study Pleistocene megafauna and the wave of extinctions — including mammoths, ground sloths, saber-toothed cats and dozens of other large mammals — that swept North America roughly 12,000 to 13,000 years ago as the last ice age ended. Understanding whether a species like M. trumani was a specialist tied to a narrow ecological niche or, as the new data suggest, a generalist capable of exploiting very different food sources in very different climates changes how researchers model which traits made animals vulnerable when the climate and prey base shifted rapidly.

The work also involved the Tr'ondëk Hwëch'in Government, a Yukon First Nation on whose traditional territory some of the fossil material was recovered. Ty Styner, the government's heritage officer, said the fossils carry meaning beyond the laboratory. "Nun Dänojà' — long-ago animals — are an important part of our Traditional Territory heritage," Styner said.

What Comes Next

Beth Shapiro, a UC Santa Cruz professor of ecology and evolutionary biology and co-director of the Paleogenomics Lab, said the genetic data also bear on why the species eventually died out. Rather than a sudden population crash, the genome showed no strong signal of the inbreeding typically seen just before a species collapses. "Miracinonyx persisted for a very long time without the signs of inbreeding we'd expect before a collapse," Shapiro said. "The decline was slow, not sudden, and that may be what left it unable to adapt when the climate shifted."

The authors say the same paleogenomic and isotopic methods can now be applied to other Ice Age carnivores whose ecology has been inferred mainly from skeletal shape, to test whether apparent specialists were in fact more flexible than their bones alone suggest. The research was also covered by Phys.org and ScienceDaily, both of which noted that the reclassification does not remove M. trumani from the broader story of pronghorn evolution so much as recast the predator that may have driven it — a puma relative that independently evolved a cheetah's build, rather than a true cheetah at all.