Bones discovered in the Bluefish Caves and a mine site in northern Yukon were initially believed to be from an ice-age puma or cougar. However, DNA analysis 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 and was working on some of her first bone samples from the Yukon.
Yukon paleontologist Grant Zazula was surprised when he received a message informing him that the cougars were actually cheetahs. Zazula noted the significant advancements in ancient DNA analysis over the past 25 years, remarking on the routine nature of genetic analysis on permafrost-preserved bones from the Yukon.
Cassatt-Johnstone identified the Yukon Miracinonyx, also known as the extinct American cheetah, and is the lead author of a paper published in Current Biology, providing new insights into the ice-age cat’s diet and habitat.
Researchers had long believed that the American cheetah, resembling today’s living cheetahs, evolved to hunt pronghorns on grassy plains. Discovering them in the Arctic tundra challenged this assumption, as pronghorns were not present in Beringia, the region where Asia and North America were once connected.
To understand how Miracinonyx survived in this environment, researchers, in collaboration with Canadian and U.S. partners, employed stable isotope analysis. This method, also used in forensics, examines chemical traces to determine ancient diets and environments. The analysis of bone samples from the cheetahs revealed a surprising preference for fish, a behavior uncommon among past and present-day cats.
The study’s findings indicated that the Yukon cheetahs relied heavily on salmon, a revelation that astonished paleontologists familiar with the species from other regions. In a region where competition for prey was fierce, turning to abundant salmon runs may have been a successful survival strategy for the cheetahs.
Genetic analysis revealed that Miracinonyx was more closely related to North American pumas than African cheetahs. Researchers also noted low genetic diversity and speculated that this limited adaptability may have contributed to the species’ extinction.
Zazula proposed renaming this unique northern population from ‘American Cheetah’ to ‘Yukon Cheetah,’ highlighting the discovery’s significance in expanding our understanding of past ecosystems. The study underscores the value of even small bone discoveries in unraveling new stories from the past.
