In a surprising turn of events, bones initially believed to be from an ice-age puma or cougar in the Bluefish Caves and a mine site in northern Yukon were reclassified through DNA analysis conducted by Molly Cassatt-Johnstone, a former lab technician at the University of California. The Yukon bones, one of Cassatt-Johnstone’s early projects, were determined not to be pumas but rather cheetahs, specifically the extinct American cheetah known as Yukon Miracinonyx.
This groundbreaking discovery led to the publication of a research paper in Current Biology by Cassatt-Johnstone, shedding new light on the ice-age cheetah’s diet and habitat. The revelation challenged previous assumptions about the American cheetah’s behavior, as researchers had believed these animals evolved to hunt pronghorns in grassy plains, a scenario incompatible with the Arctic tundra where they were found.
To unravel the mystery of how the Miracinonyx survived in this unexpected environment, researchers, in collaboration with experts from Canada and the U.S., turned to stable isotope analysis. This technique, akin to forensic analysis, delves into the chemical composition of ancient bones to decipher dietary habits, environmental conditions, and potential migration patterns.
The study unveiled a surprising revelation: the Yukon cheetahs predominantly feasted on fish, a rare feeding behavior among both past and present-day felines. This dietary adaptation was likely facilitated by the abundant Yukon salmon runs, providing an easy and plentiful food source amidst competition from larger predators like Beringian lions and giant short-faced bears.
Furthermore, genetic analysis revealed that Miracinonyx was genetically closer to North American pumas than African cheetahs. The study also highlighted the low genetic diversity within the cheetah population, possibly contributing to their eventual extinction due to limited adaptive potential.
Yukon paleontologist Grant Zazula proposed renaming this unique northern population from ‘American Cheetah’ to ‘Yukon Cheetah’ in light of these discoveries. Zazula emphasized that each new bone discovery in the Yukon uncovers a fresh chapter in the region’s prehistoric past, showcasing the ongoing evolution of scientific understanding.