During the Klondike gold rush at the turn of the 20th century, prospectors learned that there was more than just gold in the hills of Yukon, a territory in Canada.
There were fossils – lots and lots of fossils.
There were spectacular finds, too: mountains of woolly mammoth tusks, and the bones of sabre-toothed cats and extinct giant bison.
The icy rock faces also contained the tunnels and dens of prehistoric ground squirrels, which were filled with thousands of frozen pellets of ancient poop.
Many dens remained uninterrupted, but leaving these droppings on ice for another century meant the technology to analyse fossilised DNA had progressed.
In a new study, published in the journal Nature Communications, researchers have revealed a startling connection between the rodents and their massive neighbours.
The ground squirrels’ fossilised faeces contained DNA from woolly mammoths, sabre-toothed cats and bison, suggesting that the squirrels were eating meat from the larger animals.
The ancient poop, and the info dump it facilitated, is an example of “amazing preservation, recording these ecosystems over hundreds of thousands of years,” said Tyler Murchie, a paleogeneticist in British Columbia and the study’s lead author.
Murchie’s colleagues excavated hundreds of pellets of frozen faeces from the dens and brought them back to the Ancient DNA Center at McMaster University in Ontario.
There, the scientists used chemicals to break down the proteins and minerals in the coprolites to isolate any remaining DNA.
Murchie said that even the oldest samples gave off a telltale odour during this chemical digestion.
“I did not think that these would smell anymore, especially when you’re talking about 700,000-year-old poop,” he said. “It was intense.”
The idea of a squirrel feasting on flesh might seem jarring, but most rodents aren’t picky.
“If there’s a lot of seeds and nuts and other plant materials around, they’ll eat that, but if there isn’t that, or if there happens to be a carcass nearby, they’ll definitely eat that carcass,” Murchie said. – ©2026 The New York Times Company
