In the northern Yukon, bones initially presumed to be from an ice-age puma or cougar were discovered in the Bluefish Caves and a mine site. However, DNA analysis conducted by Molly Cassatt-Johnstone from the University of California revealed a different story. Cassatt-Johnstone, a lab technician fresh out of her undergraduate studies, was surprised when her preliminary analyses indicated that the bones were not from pumas as expected, but rather from cheetahs.
Grant Zazula, a Yukon paleontologist, vividly recalls the moment when he received a message informing him that the supposed cougars were actually cheetahs. This discovery marked a significant shift in the understanding of ancient DNA research, which was once considered akin to science fiction but has now become a routine practice in analyzing genetic material from permafrost-preserved bones.
Cassatt-Johnstone’s identification of a Yukon Miracinonyx, also known as the extinct American cheetah, led to her becoming the primary author of a study published in Current Biology. This research sheds new light on the diet and habitat range of these ice-age cats.
Traditionally, researchers believed that American cheetahs, resembling modern-day cheetahs with their long limbs and slender physique, would have evolved to hunt pronghorns on grassy plains. However, the discovery of these cheetahs in the Arctic tundra puzzled paleontologists, as pronghorns were not present in the Beringia region where Asia and North America once connected.
To unravel this mystery, the study team, comprising experts from Canada and the U.S., employed stable isotope analysis to investigate the dietary habits and ecological context of the Yukon cheetahs. Surprisingly, the analysis revealed that these cheetahs predominantly fed on fish, a behavior uncommon among historical and current feline species.
The study’s findings, supported by extensive DNA analysis, indicated that Miracinonyx was genetically closer to North American pumas rather than African cheetahs. The research also highlighted the low genetic diversity and limited adaptive potential of the cheetah population, possibly contributing to their eventual extinction.
In light of these discoveries, Zazula advocates for renaming this distinct northern population from ‘American Cheetah’ to ‘Yukon Cheetah,’ emphasizing the significance of every bone found in uncovering new insights into the past.