In the past, remains discovered in the Bluefish Caves and a mining location in northern Yukon were initially believed to be from an ice-age puma or cougar. However, DNA testing conducted by the University of California revealed a different story. Molly Cassatt-Johnstone, a former lab technician fresh out of her undergraduate studies, conducted the analysis on the Yukon bones, which were among her first samples. She was surprised when the results showed that the bones were not from pumas but from cheetahs.
Grant Zazula, a paleontologist from Yukon, vividly recalls his astonishment upon receiving the message that the supposed cougars were, in fact, cheetahs. The discovery of ancient DNA was once considered almost like science fiction two decades ago, but now, genetic analysis on permafrost-preserved bones from the Yukon has become a routine practice for researchers.
Cassatt-Johnstone made history by identifying a Yukon Miracinonyx, also known as the extinct American cheetah, and is now the lead author of a study published in Current Biology that provides new insights into the ice-age cat’s diet and habitat range.
Experts had long believed that the American cheetah, resembling the modern-day cheetahs with their long limbs and slender physique, evolved to hunt pronghorns in grassy plains. The discovery of these cheetahs in the Arctic tundra puzzled paleontologists, as there were no pronghorns in Beringia, the region where Asia and North America once connected.
To unravel the mystery of how Miracinonyx survived in the Arctic, researchers, in collaboration with teams from Canada and the U.S., employed stable isotope analysis. This technique, commonly used in forensics, examines chemical signatures to determine ancient diets and environmental conditions, shedding light on potential travel patterns. Through meticulous analysis of bone fragments from the cheetah’s limbs, researchers uncovered that the Yukon cheetahs predominantly fed on fish, a behavior uncommon among historical and contemporary feline species.
Julie Meachen, a paleontologist specializing in mammalian carnivores from the Late Pleistocene, expressed astonishment at the findings, noting the stark contrast in behavior between Yukon cheetahs and those in midcontinental North America. In a region teeming with formidable predators, the cheetahs likely turned to the plentiful Yukon salmon runs as a strategic food source.
The study further revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs. Researchers also highlighted the low genetic diversity within the cheetah population, suggesting a potential factor in their extinction. Grant Zazula proposed renaming this distinct northern group from ‘American Cheetah’ to ‘Yukon Cheetah,’ emphasizing the significance of each new bone discovery in unraveling the region’s ancient fauna mysteries.