Prehistoric Yukon ‘cheetahs’ were fish eaters, not really cheetahs at all: study

Slender, agile cheetahs that roamed the Yukon 30,000 years ago were not technically cheetahs at all, but relatives of the puma that adapted to mostly eat fish instead of antelopes in a harsh northern climate, new research shows.

A study published in the journal Current Biology analyzed fossils found in the Yukon and Wyoming in the United States belonging to Miracinonyx trumani, also known as the “American cheetah.”

With their gracefully slim bodies and long legs, the now-extinct cats appeared to resemble African cheetahs.

But the researchers found the cats were actually closer relatives of the puma, having diverged from the puma lineage around 2.6 million years ago as growing grasslands and cooling temperatures drove diversification in many North American mammals.

Grant Zazula, a paleontologist for the Yukon government and one of the study’s co-authors, said the species’ identification in the territory was interesting because the pronghorn antelope hunted by their southern counterparts never existed there.

The researchers wanted to find out what the Yukon cats were eating instead, so they sent the fossils for analysis. The results showed a chemical signature that matched other fish-eating predators like grizzly bears, Zazula said.

In fact, the Yukon cats adapted to eat mostly fish, a unique preference compared to the more diverse diet favoured by their southern kin.

“We’ve never seen a cat behave like this before,” Zazula said in an interview Thursday.

He said the cats likely made the change to adapt to their new environment after travelling farther north into a Yukon that was vastly different 30,000 years ago.

Gone were the boreal forests with their spruce trees and animals such as moose found in modern-day Yukon. Instead, the cats would have faced tree-barren grasslands and walked alongside woolly mammoths, wild horses, bison and other large mammals.

“Because there were so many of these big herbivorous animals on the landscape, we had lots of carnivores that were eating them,” Zazula said. The other predators included lions, sabretooth cats, wolves and grizzly bears.

The Yukon cheetahs would have had to find their niche in a competitive and unforgiving environment, Zazula added.

Luckily, the region’s rivers were rich with salmon and the cats could eat fish carcasses along the banks or have their pick from fish-packed spawning grounds.

Their distinct diet was likely key to their survival in the north, Zazula said.

“In order to live and be successful in the Yukon during the Ice Age, it had to figure out its way to live. And that fishing niche wasn’t occupied,” he said.

The Yukon environment also had an impact on the cats’ genetics, the researchers found. Two of the genes that regulate circadian rhythm — essentially the body’s internal alarm clock that reacts to changes in brightness — were non-functional in the cats.

It could be because the animals had to adapt to seasonal extremes of sunlight and darkness because of their high-altitude homes, or the cats could have been nocturnal.

The cats eventually went extinct after they couldn’t adapt to ecosystem changes at the end of the Ice Age.

But Zazula said their hardiness in adapting to their Yukon environment had parallels to the people who now live there.

“Everybody that moves to the Yukon has to figure out a different way to live if you’re not from here,” he said. “(The cats) made their way, they figured it out by adapting to new resources and new environmental conditions. It became something unique — the Yukon cheetah.”

This report by The Canadian Press was first published Sept. 4, 2026.