DNA in Arctic Ground Squirrel Faeces Reveals 700,000-Year-Old Beringian Ecosystem

DNA preserved in frozen faecal pellets left by Arctic ground squirrels has revealed a complex ice-age ecosystem in what is now central Yukon, Canada, spanning roughly 700,000 years. Researchers examined coprolites from 13 burrows dated between about 30,000 and 700,000 years ago. Each pellet measured 1 to 2 centimetres long.

From the samples they recovered genetic sequences belonging to microbes, more than 200 plant groups, insects, other rodents, woolly mammoths, horses, grey wolves, steppe bison and a big cat identified as either an American cheetah or a cougar. ” Arctic ground squirrels, rodents about 40 centimetres long, inhabit cold regions of North America and Siberia—areas once connected by the Beringian land bridge.

The squirrels remain active for roughly four months each year and spend the remaining eight months hibernating.

During their active period they gather and cache food, which often includes animal remains; reports document them consuming carcasses of moose and lynx. Murchie noted that finding DNA from large mammals in the pellets is therefore unsurprising. The team reconstructed mitochondrial genomes from the coprolite DNA, including sequences from 12 ground squirrels—one lineage extending back 700,000 years—three horses, two bison, one hare and six woolly mammoths.

Details of the mammoth genomes will appear in a separate publication. ” She cautioned that DNA from any species could have entered the pellets either through direct consumption or environmental leaching, though the quantity of mammoth DNA and the squirrels’ scavenging behaviour make consumption plausible. 1038/s41467-026-72977-6.

Duane Froese of the University of Alberta participated in locating the ancient faecal pellets in Yukon permafrost.