Bones discovered in the Bluefish Caves and a mining site in northern Yukon were initially believed to be from an ice-age puma or cougar. However, DNA analysis conducted at the University of California revealed a different story.
The testing was carried out by Molly Cassatt-Johnstone, who was a recent undergraduate lab technician at the time working on some of her first samples, including the Yukon bones. Upon realizing that the specimens did not resemble pumas, she was surprised and initially thought she had made an error.
Yukon paleontologist Grant Zazula recalled his astonishment upon receiving a message stating that the cougars were not actually cougars but cheetahs. According to Zazula, examining ancient DNA was once considered almost like science fiction, but it has now become a routine practice when analyzing genetic material from permafrost-preserved bones in the Yukon.
Cassatt-Johnstone successfully identified a Yukon Miracinonyx, commonly known as the extinct American cheetah. She is now the lead author of a study published in Current Biology, providing new insights into the ice-age cat’s diet and habitat.
‘A Fascinating Mystery Unfolds’
Previously, researchers believed that the American cheetah, resembling modern cheetahs with their long legs and slender build, would have evolved to hunt pronghorns on grasslands. Discovering these animals in the Arctic tundra puzzled paleontologists.
Cassatt-Johnstone noted that the cheetahs were initially thought to be specialized predators of American pronghorn antelope in the lower 48 states, but since there were no pronghorn in Beringia, their presence there raised questions.
Beringia, the region where Asia and North America were once connected, includes parts of Russia, Alaska, and the Yukon.
To understand how Miracinonyx thrived in this environment, the study, involving researchers from Canada and the U.S., utilized stable isotope analysis. This technique, also employed in forensics, examines chemical signatures to determine the diet and environmental conditions of ancient organisms.
By analyzing bone fragments from the cheetah’s paw and leg, researchers, led by Matthew Wooller, identified a unique diet preference for fish, a behavior uncommon among historical and contemporary feline species.
Julie Meachen, a paleontologist specializing in mammalian carnivores from the Late Pleistocene, expressed surprise at the findings, noting that the Yukon cheetahs exhibited distinct behavior from their counterparts in Wyoming.
In a region teeming with formidable predators like Beringian lions and giant short-faced bears, the cheetahs likely turned to the abundant Yukon salmon as a reliable food source.
The study also revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs and had a limited gene pool, indicating low population numbers, which may have contributed to their extinction.
Zazula proposed renaming this unique northern population from ‘American Cheetah’ to ‘Yukon Cheetah’ in light of the discovery of these Arctic fishing felines, emphasizing the continuous potential for new revelations in paleontology.