In the initial discovery, bones uncovered in the Bluefish Caves and a mining location in northern Yukon were initially thought 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. These Yukon bones were among her first sample analyses, leading her to realize they did not resemble pumas at all.
Yukon paleontologist Grant Zazula vividly recalls his surprise upon receiving a message one evening stating, “Hey Grant, your cougars aren’t cougars — they’re actually cheetahs.” Zazula reflects on how ancient DNA analysis was once considered akin to science fiction, but now it has become a routine practice in examining genetic material from permafrost-preserved bones in the Yukon.
Cassatt-Johnstone made history by identifying a Yukon Miracinonyx, also known as the extinct American cheetah. She now serves as the primary author of a published paper in Current Biology that offers fresh insights into the ice-age cat’s diet and habitat.
Paleontologists had previously assumed that the American cheetah, resembling today’s agile cheetahs with long limbs, would have evolved to pursue pronghorns across grassy plains. Discovering these creatures in the Arctic tundra presented a challenge for researchers.
The researchers turned to stable isotope analysis, a method used in forensics, to investigate the dietary habits and environmental conditions of the Yukon cheetahs. The analysis of bone fragments indicated that these cheetahs primarily consumed fish, a behavior uncommon among historical and contemporary felines.
This unexpected diet preference raised questions about how the Miracinonyx managed to survive in the region. The study revealed that Yukon cheetahs had adapted to rely on the abundant salmon runs, which may have provided them with a strategic advantage in a competitive environment with larger predators.
Furthermore, the study’s extensive DNA analysis showed that Miracinonyx was genetically closer to North American pumas than African cheetahs. The researchers also examined the genetic diversity within the cheetah population, concluding that their low numbers may have contributed to their extinction.
Zazula proposed renaming this distinct northern population from ‘American Cheetah’ to ‘Yukon Cheetah,’ highlighting the significance of ongoing discoveries in paleontology. The findings underscore the importance of every new bone discovery in shedding light on the diverse species that once inhabited the Yukon region.