A discovery in the Bluefish Caves and a mine site in northern Yukon initially pointed to the presence of an ice-age puma or cougar. However, DNA testing from the University of California yielded surprising results. Molly Cassatt-Johnstone, a lab technician fresh out of her undergraduate studies, conducted the analysis on the Yukon bones, which were among her first specimens. The findings diverged from expectations, leading to the revelation that the bones were not from pumas but from cheetahs.
Grant Zazula, a Yukon paleontologist, vividly recalls his astonishment upon receiving a message revealing the true identity of the bones as cheetahs, not cougars. The study, published in Current Biology and led by Cassatt-Johnstone, uncovers new insights into the diet and habitat range of the ice-age creature known as Yukon Miracinonyx, or the extinct American cheetah.
Researchers had long believed that the American cheetah, resembling today’s cheetahs in physique, evolved to hunt pronghorns on grassy plains. The unexpected discovery of these cheetahs in the Arctic tundra puzzled paleontologists. Beringia, the region connecting Asia and North America, including parts of Russia, Alaska, and the Yukon, served as the cheetahs’ habitat, posing questions about their survival in the area devoid of pronghorns.
The study, involving collaborators from Canada and the U.S., employed stable isotope analysis to investigate the cheetahs’ dietary habits. The results unveiled a peculiar behavior: the Yukon cheetahs predominantly consumed fish, a rarity among both historical and present-day feline species. The shift to a fish-based diet in a region teeming with competing predators like Beringian lions and giant bears was deemed a strategic move due to the abundance of Yukon salmon.
Additionally, genetic analysis revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs. The study highlighted the low genetic diversity and limited adaptive potential of the cheetah population, factors that might have contributed to their eventual extinction. Zazula suggested renaming the unique northern population from ‘American Cheetah’ to ‘Yukon Cheetah’ based on the discoveries made, emphasizing the continuous surprises unearthed by paleontologists in the Yukon region.