It is now widely accepted through ancient mitochondrial DNA analysis that North America’s Pleistocene “cheetahs” were actually offshoots of the modern cougar lineage and were not directly ancestral to the cheetah of the Old World.
However, these mitochondrial DNA studies did not reveal the full picture. A full genome sequence was recently mapped from a specimen of Miracinonyx trumani, and this full genome has been compared to similar genomes of North American and South American cougars.
The researchers found something quite amazing. We thought that the original population of North American cougars went extinct at the end of the Pleistocene as did the two “cheetahs.” About 8,000 years ago, cougars from South America recolonized North America, and these cougars that came into North America are the ancestors of the living cougars on this continent.
And because of the limited genetic diversity of the North American cougar, this 8,000 year point of origin is most likely.
However, what is particularly interesting is that between 8-12 percent of the North American cougar’s genome apparently comes from Miracinonyx trumani. Estimates of when this introgression happened based upon the molecular clock suggest an entrance into the ancestral North American cougar 7,700-8,100 years ago.
So Miracinonyx trumani apparently lasted a few thousand years after the end of the Pleistocene, and when South American cougars recolonized North America, they mated with the now extinct “cheetah” species. This hybridization could have conferred upon these newly colonizing cougars some important alleles for surviving at temperate latitudes, which tropical cougars may have lacked.
Humans certainly were aware of the existence of the North American “cheetahs,” and if they survived to this late date, stories of their existence could have existed throughout indigenous American cultures.
Perhaps these cats lasted even longer, maybe even giving credence to the legendary Mexican onza.