Initially, bones discovered in the Bluefish Caves and at a mining site in northern Yukon were believed to be from an ice-age puma or cougar. However, DNA analysis conducted by the University of California revealed a different story. The examination was carried out by Molly Cassatt-Johnstone, a lab technician who had recently completed her undergraduate studies. These Yukon bones were among the first samples she had worked on. Upon conducting the initial analyses, which did not resemble pumas at all, Cassatt-Johnstone humorously recalled thinking she had made a grave mistake.
Yukon paleontologist Grant Zazula vividly recalls his surprise upon receiving a message one evening stating, “Hey Grant, your cougars are not cougars — they are actually cheetahs.”
Zazula remarked that twenty-five years ago, delving into ancient DNA seemed like science fiction, akin to “Jurassic Park.” He noted that genetic analysis on permafrost-preserved bones from the Yukon has now become a routine practice.
Cassatt-Johnstone was the first to identify a Yukon Miracinonyx, also known as the extinct American cheetah. She is now the lead author of a paper published in Current Biology, offering fresh insights into the ice-age cat’s diet and habitat.
‘A Fascinating Mystery Unraveled’
Researchers had long assumed that the American cheetah, resembling today’s cheetahs with their long limbs and sleek physique, would have evolved to pursue pronghorns across grassy plains. Discovering them in the Arctic tundra puzzled paleontologists.
Cassatt-Johnstone explained that they were initially believed to be highly specialized predators of American pronghorn antelope in the lower 48 states but noted the absence of pronghorn in Beringia.
Beringia, the land where Asia and North America were once connected, encompassing present-day Russia’s easternmost region, Alaska, and the Yukon, posed the question of how Miracinonyx survived there.
To address this query, the study team, in collaboration with Canadian and U.S. partners, utilized stable isotope analysis. This method, commonly employed in forensics, examines chemical traces to determine the diet and environmental conditions of ancient beings or animals, shedding light on their potential movements during their lifetime.
Small bone fragments from the cheetah’s paw and leg, scrutinized through a meticulous process, provided insights comparable to distinguishing between someone consuming plain carrots or carrot cake, as explained by Matthew Wooller, director of the Alaska Stable Isotope Facility at the University of Alaska Fairbanks.
Wooller expressed his determination to crack the case upon reviewing preliminary findings, emphasizing the unprecedented nature of the data from an isotopic perspective.
The research unveiled that Yukon cheetahs primarily subsisted on fish, a behavior uncommon among past and present-day felines, pointing to a unique ecological adaptation. Wooller likened understanding the ecosystem to solving a complex puzzle with missing pieces.
Salmon Enthusiasts: Yukon Cheetahs
This revelation astonished paleontologists like Julie Meachen, specializing in Late Pleistocene mammalian carnivores and extensively studying this species in Wyoming.
Meachen highlighted the distinct behavior of the Yukon cheetahs compared to those in midcontinental North America, suggesting a divergence almost akin to different species.
In a region where these relatively small cheetahs competed with colossal Beringian lions, scimit