Ancient DNA shows the 'American cheetah' was a puma relative, not a true cheetah

The animal known for more than a century as the American cheetah was not a cheetah at all, according to ancient DNA extracted from Ice Age fossils recovered from Wyoming to the Yukon. The extinct predator, formally named Miracinonyx trumani, turns out to be a close cousin of the modern puma that independently evolved a lean, long-legged build resembling Africa's sprinting cats — and, in its northernmost range, gave up chasing land mammals altogether in favor of eating salmon.

The findings, led by researchers at the University of California, Santa Cruz's Paleogenomics Lab, were published Sept. 4 in the journal Current Biology. They rely on nuclear paleogenomes — not just fragments of DNA, but reconstructions of large stretches of the animal's genome — sequenced from four fossils dated to between 23,000 and 31,000 years old, combined with chemical analysis of the bones themselves.

The numbers

The genetic data place M. trumani as a sister lineage to the puma, Puma concolor, with the two species sharing a common ancestor roughly 2.6 million years ago. That is far more recent than the animal's split from true cheetahs, genus Acinonyx, which the study puts at about 4.7 million years ago — meaning the resemblance between the American and African cats is a case of convergent evolution, not shared ancestry.

Three of the four fossils came from the Yukon, including specimens from Bluefish Caves and a mine site at Upper Quartz Creek, and had previously been catalogued as belonging to a different, unidentified cat. The DNA work confirmed they were M. trumani, extending the species' known range more than 20 degrees of latitude farther north than earlier fossil evidence had shown. Isotope analysis of those Yukon bones produced a chemical signature matching fish-eating predators such as grizzly bears, indicating the northern population lived largely on anadromous fish, likely salmon. A fourth fossil, from Natural Trap Cave in Wyoming, carried an isotopic signature typical of a hunter of terrestrial herbivores such as pronghorn antelope. Adults of the species weighed around 150 pounds and stretched roughly 8 feet from nose to tail.

A range that reached the Arctic

Miracinonyx trumani has been part of the North American fossil record since fragments were first attributed to a distinct genus in the 1970s, and its cheetah-like skull and limb proportions gave rise to a long-standing evolutionary story: that the pronghorn's extraordinary speed, unmatched by any living North American predator, was a defense shaped by millennia of pursuit from this cat. Researchers have since found reasons to complicate that picture. A 2023 study in Biology Letters examined the animal's elbow joint and found it intermediate between a puma's and a cheetah's, suggesting M. trumani retained some ability to grasp and manipulate prey with its forelimbs that true sprint specialists like the cheetah have lost.

The new genomic work goes further, showing that the animal's ecology was not uniform across its range at all. Southern populations in places like Wyoming and Florida behaved as generalist grassland predators. Their northern relatives, isolated in Beringia at the edge of the last Ice Age's ice sheets, evolved into fish specialists instead — a niche with no equivalent among cheetahs, pumas or other cats living today. The study also found loss-of-function mutations in genes that regulate circadian rhythm, which the authors say may reflect adaptation to the extreme seasonal swings of daylight at high latitudes, and identified a nonfunctional sour-taste receptor gene, an unusual trait even among felids.

Reaction

The research was led by Molly Cassatt-Johnstone, a Ph.D. candidate in the Paleogenomics Lab at UC Santa Cruz, with senior author Beth Shapiro, a professor of ecology and evolutionary biology who co-directs the lab. Matthew Wooller, a professor at the University of Alaska Fairbanks who directs the Alaska Stable Isotope Facility, led the chemical analysis of the bones, and Grant Zazula, a paleontologist with the Yukon government, contributed fossils and regional expertise — pronghorn, as Zazula has noted, never lived in the Yukon, underscoring how different the diet of the northern cats had to be.

"These cats were remarkably flexible, much like pumas are across their range today."

The quote belongs to Cassatt-Johnstone, describing what she called one of the more striking outcomes of the analysis. "It was just so cool to see that these cats behaved like totally different predators depending on where they were," she said of the split between fish-eating northern populations and grassland-hunting southern ones. Wooller framed the same result in terms of specialization at both extremes of a single species' range: "They're demonstrating über-specialization at two ends of their range, while also feeding on two completely different food sources." Larisa DeSantis, a paleoecologist at Vanderbilt University who was not involved in the study, called the adaptability itself the notable part of the story, saying it was "really cool to see that sort of adaptability" in an animal long treated as a narrow specialist built for one thing: running down pronghorn.

What happens next

The reclassification does not erase Miracinonyx trumani from the fossil record or from popular science writing overnight, but it does put pressure on museum labels, textbook diagrams and documentary scripts that have long presented the animal as a cheetah relative that chased pronghorn across the Great Plains. Cassatt-Johnstone has argued the common name itself is part of the problem: "Calling it the American cheetah implies a specific behavior and ecology, which isn't necessarily appropriate," she has said, given how differently the species apparently lived depending on latitude.

The species is thought to have persisted in North America from roughly 2.5 million years ago until its extinction near the end of the last Ice Age, alongside mammoths, ground sloths and other Pleistocene megafauna. The Current Biology paper reports that the population showed low genetic diversity and a gradual long-term decline rather than a sudden crash, a pattern the authors say merits comparison with other Ice Age carnivore extinctions. Researchers involved in the project say additional fossils from Beringia and the contiguous United States could sharpen the picture of when the northern and southern populations diverged in behavior, and whether other extinct predators long treated as narrow specialists were, as this study suggests, considerably more flexible than their fossils alone let on.