In the Bluefish Caves and a mine site in northern Yukon, bones initially believed to be from an ice-age puma or cougar were found. A DNA analysis from the University of California revealed a surprising truth. The test, conducted by Molly Cassatt-Johnstone, a recent lab technician graduate at the time, marked her early work on Yukon bones.
Yukon paleontologist Grant Zazula vividly recalls his astonishment upon receiving a message indicating that the supposed cougars were actually cheetahs. Zazula reflects on the evolution of genetic analysis, noting that studying ancient DNA was once considered akin to science fiction, but is now a routine practice, especially with permafrost-preserved bones from the Yukon.
Cassatt-Johnstone’s identification of a Yukon Miracinonyx, the extinct American cheetah, marked a significant discovery. She is now the primary author of a paper published in Current Biology that offers fresh insights into the ice-age cat’s diet and habitat.
Scientists long believed that the American cheetah, resembling today’s cheetahs with their lengthy limbs and slender physique, would have adapted to pursue pronghorns across grassy plains. Discovering them in the Arctic tundra puzzled paleontologists, as pronghorns were not present in Beringia, the landmass connecting Asia and North America.
To unravel this mystery, researchers employed stable isotope analysis, a method also used in forensics to trace dietary habits and environmental conditions. The analysis of bone fragments from the cheetahs’ limbs revealed a surprising diet primarily consisting of fish, a behavior uncommon among past and present felines.
The revelation that Yukon cheetahs heavily relied on salmon astonished paleontologists like Julie Meachen, who specializes in Late Pleistocene mammalian carnivores. The abundance of fish in the region likely made it an easy hunting ground for the relatively small cheetahs, especially amidst competition from larger predators like Beringian lions and giant bears.
Further genetic analysis revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs. The study also highlighted the low genetic diversity in the cheetah population, potentially contributing to their extinction.
Zazula proposes renaming this distinct northern population from ‘American Cheetah’ to ‘Yukon Cheetah,’ emphasizing the importance of every bone discovery in unraveling new stories from the past.