Ancient DNA Pushes American Cheetah 20 Degrees North, Suggests Fish Diet

Q: Did an extinct Ice Age cheetah actually survive by hunting salmon in the frozen Arctic?

Probably in part, but the evidence does not prove these cats literally survived by actively catching salmon themselves. The new study makes a strong case that the Yukon fossils belonged to *Miracinonyx trumani*, the extinct “American cheetah,” and that these northern animals lived about 31,000 to 34,000 years ago in Arctic Yukon. Chemical evidence from their bones is the key clue: unusually high nitrogen isotope values and amino-acid analysis place them at a trophic level consistent with predators tied to an aquatic food web. The researchers say that pattern fits a diet involving migratory fish such as salmon, or prey that had themselves fed on fish. What the data do not show is the exact behavior. Isotopes can indicate the kind of food web an animal depended on, but they cannot reveal whether *Miracinonyx* was wading into streams to catch fish, scavenging salmon carcasses along riverbanks, or eating other fish-eating animals. So “hunting salmon” is plausible, but not directly demonstrated. What is clear is that the Arctic population seems to have eaten very differently from a Wyoming *Miracinonyx* dated to about 23,500 years ago, which shows the signature of a more typical terrestrial carnivore. That contrast suggests the species was far more adaptable than its nickname implies. So the best answer is that the extinct cat likely relied heavily on an aquatic food chain in the Yukon, quite possibly including salmon, but the study stops short of proving direct salmon hunting.

Q: If this ancient cat adapted to aquatic diets, what mysterious event ultimately triggered its extinction?

There is no single proven “mysterious event” identified in this study. The best evidence is that *Miracinonyx trumani* disappeared amid the broad ecosystem upheaval at the end of the last Ice Age, roughly 16,000 to 13,000 years ago, when warming climate, habitat shifts, and collapsing Pleistocene food webs drove many large mammals extinct. The new paper shows the species was adaptable enough to exploit very different diets, including probable fish-based food webs in Arctic Yukon and more typical terrestrial prey farther south. But the researchers also found that its population size had been declining for about a million years and that it had low genetic diversity. That suggests the cat was already vulnerable long before its final disappearance. The searched reporting adds that the species likely “couldn’t adapt to ecosystem changes at the end of the Ice Age.” In other words, even unusual flexibility—such as possible salmon use in the north—did not save it from the sweeping environmental reorganization that ended the Pleistocene. Scientists still debate the exact mix of forces behind many late Ice Age extinctions in North America. Climate warming, shifting prey availability, loss of open habitats, competition within changing carnivore communities, and possibly human pressures are all commonly discussed. But based on the evidence provided here, the extinction trigger for this cat is not pinned to one confirmed event; it is most plausibly tied to end-Ice Age ecological collapse.

3 articles · Updated · spacedaily.com · Sep 7

Three Yukon fossils dated to 31,000-34,000 years ago were reidentified as Miracinonyx trumani, placing the American cheetah in Arctic Yukon more than 20 degrees north of its previously known range.
A 38-fold Yukon genome and a 22-fold Wyoming genome show the species was the puma's closest known relative, not the African cheetah's, with the split from pumas estimated at about 2.6 million years ago.
Nitrogen signatures in the Yukon bones ran about 6 parts per thousand above other regional carnivores, and amino-acid analysis put two northern animals at trophic position 4, consistent with feeding through an aquatic food chain.
The study stops short of proving fish consumption directly: no fish remains tied to the cats were reported, and the authors present migratory fish use as the simplest explanation rather than an observed behavior.
Genomic histories from the Yukon and Wyoming animals also indicate a long population decline from near 100,000 to under 10,000 effective individuals by 70,000 years ago, while the paper says more museum specimens may be misidentified as puma.