In the beginning, bones unearthed in the Bluefish Caves and at a mining location in northern Yukon were initially believed to be from an ice-age puma or cougar. However, DNA testing conducted by the University of California revealed a different story. The analysis was carried out by Molly Cassatt-Johnstone, a lab technician who had recently completed her undergraduate studies. These Yukon bones were among the first samples she had worked on, and upon initial analysis, they did not resemble pumas at all, leading to a surprising discovery that they were actually cheetahs.
Yukon paleontologist Grant Zazula was astounded when he received the message informing him that the supposed cougars were, in fact, cheetahs. Reflecting on the advancements in ancient DNA analysis, Zazula noted that examining genetic material from permafrost-preserved bones in the Yukon has become a routine practice compared to the past when it seemed like a concept from science fiction.
Cassatt-Johnstone made history by identifying a Yukon Miracinonyx, also known as the extinct American cheetah. She is now the lead author of a study published in Current Biology that provides fresh insights into the ice-age cat’s diet and habitat. Researchers were puzzled by the discovery of American cheetah remains in the Arctic tundra, as these creatures were thought to have evolved to hunt pronghorns on grassy plains, a prey species absent in the Beringia region, where Asia and North America once connected.
To unravel this mystery, the study team, in collaboration with Canadian and U.S. partners, employed stable isotope analysis. This technique, commonly used in forensics, examines chemical markers to determine the diet and environmental conditions of ancient organisms. By analyzing bone fragments from the cheetah’s limbs, researchers discovered that the Yukon cheetahs primarily fed on fish, a behavior uncommon among past and present feline species.
The revelation that Yukon cheetahs predominantly consumed salmon was a breakthrough for paleontologists like Julie Meachen, who specializes in studying mammalian carnivores from the Late Pleistocene era. Despite facing competition from larger predators like Beringian lions and scimitar cats, the cheetahs’ adaptation to fish-rich environments may have contributed to their survival. The study also revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs, with a limited genetic diversity that could have played a role in their extinction.
Zazula proposed renaming this distinct northern population from ‘American Cheetah’ to ‘Yukon Cheetah,’ emphasizing the significance of each new bone discovery in shedding light on the region’s prehistoric biodiversity.
