700,000-year-old squirrel poop reveals a lost Arctic world of mammoths, horses, and giant predators

Researchers from McMaster University and the University of Alberta analyzed fossilized Arctic ground squirrel droppings from Yukon permafrost, uncovering genetic material from mammoths, steppe bison, horses, wolves, and large predators like cougars or cheetah-like species. The samples, dated between 30,000 and 700,000 years old, also contained DNA from over 200 plant groups, offering a snapshot of Beringia’s ancient ecosystems. Unlike bones, which only confirm species presence, these coprolites preserved environmental DNA from prey, predators, and plants, reconstructing complex food webs. The study, published in *Nature Communications*, highlights how squirrels act as natural archives: their burrows seal organic material in permafrost, slowing DNA decay. Lead author Tyler Murchie of the Hakai Institute noted that mitochondrial DNA resilience and frozen conditions allowed recovery of 18 genomes, including woolly mammoth and steppe bison lineages. This method could revolutionize paleogenomics by using coprolites as multiplexed ecosystem records. Previously, Arctic paleontology assumed fossil ground squirrels represented a single lineage, but genetic data revealed unexpected diversity, including a 700,000-year-old lineage linked to modern Siberian relatives. Evolutionary geneticist Hendrik Poinar suggested these findings could inform climate adaptation models for today’s species. The study also challenges assumptions about species continuity, showing genetic turnover over glacial periods. The research underscores how coprolites bridge gaps in fossil records, offering insights into predator-prey dynamics and plant interactions. By analyzing DNA from ingested, inhaled, or cached materials, scientists gained a holistic view of Arctic ecosystems lost for millennia. This breakthrough may redefine how ancient environments are studied, leveraging preserved scat as a time capsule of Earth’s past.