They've got to get out there and eat as much as they can of everything
In the permafrost of Canada's Yukon, the humble burrows of arctic ground squirrels have yielded something extraordinary: a genetic archive spanning 700,000 years, preserved not in bone or amber, but in frozen feces. Researchers at McMaster University, following the unglamorous trail of ancient droppings, have reconstructed the DNA of woolly mammoths, wolves, and vanished ecosystems — a reminder that nature's most profound records are often kept in the most unlikely places. The discovery reframes what counts as a scientific artifact, and quietly asks how much of the past remains hidden beneath the ice, waiting for the right question.
- A team expecting to study squirrel microbiomes instead uncovered a 700,000-year biological time capsule buried in permafrost — one of the most significant paleogenomic finds in recent memory.
- The sheer improbability creates tension: ancient mammoth DNA, preserved not in tusks or bones, but in the digestive waste of a small hibernating rodent, challenges every assumption about where the past survives.
- Researchers used computational genomics to reconstruct 18 mitochondrial genomes — including six woolly mammoths from distinct eras — proving feces a legitimate and powerful tool for reading deep time.
- The publicly released data now feeds directly into de-extinction ventures like Colossal's mammoth project, though scientists caution the result would be an engineered approximation, not a true resurrection.
- The team is already preparing a follow-up study on mammoth evolution, suggesting this frozen archive has far more to say — and that the Yukon permafrost may hold many more such capsules yet unopened.
In the frozen depths of Canada's Yukon, scientists at McMaster University have made one of paleogenomics' most improbable discoveries: ancient DNA preserved in the frozen feces of arctic ground squirrels, spanning a window of 3,000 to 700,000 years. Among the genetic material recovered were traces of woolly mammoths, wolves, bison, horses, a cheetah, and hundreds of plant species — an entire vanished ecosystem, catalogued in the droppings of a small hibernating rodent.
The preservation owes itself to the squirrel's own biology. Active for only four months a year, arctic ground squirrels pack their burrows with everything edible — seeds, bones, fur, plant matter — before retreating into hibernation. Over millennia, rising permafrost sealed some of these burrows entirely, creating accidental time capsules. In one, researchers found a squirrel frozen mid-sleep, never to wake again.
Lead researcher Tyler Murchie acknowledges the find lacks glamour. Yet using computational methods to reassemble fragmented genetic material, the team reconstructed 18 mitochondrial genomes, including six from woolly mammoths of different eras. The work establishes feces as a legitimate — and long-overlooked — medium for paleogenomic research, capable of capturing not just individual species but the full biological texture of an ancient environment.
The findings land at a charged moment. Colossal, a U.S. company pursuing mammoth de-extinction through genetic engineering, now has access to the team's publicly released data. Experts are measured in their enthusiasm: the creature that might eventually emerge would be an Asian elephant bearing mammoth-like traits, not a true revival. What endures beyond the corporate ambition is something quieter — the wonder of a discovery that no one was looking for, hidden for hundreds of thousands of years in the frozen waste of a creature smaller than your hand.
In the frozen depths of Canada's Yukon territory, scientists have stumbled upon one of paleogenomics' most unlikely archives: the droppings of arctic ground squirrels, sealed away in permafrost for hundreds of thousands of years. The discovery, announced this week by researchers at McMaster University, has yielded genetic material spanning between 3,000 and 700,000 years—a window into deep time that includes DNA from woolly mammoths, wolves, bison, horses, a cheetah, and hundreds of plant species.
Tyler Murchie, the lead researcher on the study published in Nature Communications, acknowledges the unglamorous nature of the find. Digging through ancient feces lacks the romance of unearthing a mammoth tusk. Yet what emerged from those burrows was, by any measure, spectacular. The team had initially set out to study the squirrels' own microbiome. Instead, they found themselves cataloging the biodiversity of an entire ecosystem frozen in time.
The mechanism behind this preservation is elegantly simple. Arctic ground squirrels are awake for only about four months each year, spending the rest in hibernation. During their brief active season, they must consume everything available—nuts, seeds, leaves, bones, fur, whatever they can gather. They pack their burrows with this material, creating dense caches of biological matter. Over millennia, rising permafrost sealed some of these burrows completely, transforming them into perfectly preserved time capsules. In one burrow, researchers even found a squirrel itself, frozen in the moment it lay down to sleep one season and never woke.
Using computational methods to stitch together fragmented DNA like puzzle pieces, the team reconstructed 18 mitochondrial genomes, including six from woolly mammoths that lived in different eras. This genetic data offers insights not just into individual species but into how life itself has transformed across hundreds of thousands of years. The work demonstrates that feces—long overlooked in paleogenomic research—can be as informative as bone or tissue, perhaps more so, because it captures the full biological context of an ancient environment.
The findings arrive at a moment when de-extinction has moved from science fiction into corporate venture. Colossal, a U.S. company, has announced plans to resurrect the woolly mammoth using genetic engineering. Murchie's team has made their data publicly available for such efforts, though he notes with characteristic understatement that the company already possesses vast genetic resources. The resulting animal, experts caution, would be less a true mammoth than an Asian elephant with mammoth-like modifications—a distinction that matters more than the marketing suggests.
What strikes Murchie most is the sheer improbability of the discovery itself. Ancient DNA from squirrel feces. A frozen squirrel in its burrow. Genetic echoes of mammoths that walked the earth thousands of years ago, preserved in the digestive waste of a small rodent. The team is preparing another study on what this DNA reveals about mammoth evolution, details Murchie describes only as "super cool"—a reminder that even in the age of genomic sequencing and de-extinction ambitions, the simple act of discovery still carries its own quiet wonder.
Notable Quotes
Digging through squirrel poop might sound less appealing than discovering a mammoth tusk, but the spectacular amount of information uncovered suggests feces is an overlooked way to see into our planet's distant past.— Tyler Murchie, paleogenomics researcher at McMaster University
I can't believe that we were able to get these insights from squirrel faeces.— Tyler Murchie
The Hearth Conversation Another angle on the story
Why squirrel droppings? Of all the places to find ancient DNA, why there?
Because of how arctic ground squirrels live. They're awake four months a year, and in that time they have to eat everything they can find and pack it into their burrows. Over thousands of years, permafrost sealed those burrows shut. It's like they created their own museums without knowing it.
So the squirrels were just... hoarding?
Exactly. They were doing what they needed to survive. But what they were actually doing was collecting samples from their entire ecosystem—plants, bones, fur, everything. And then the permafrost locked it all in place.
How old is this material?
Between 3,000 and 700,000 years old. So you're looking at genetic snapshots from vastly different periods. Six woolly mammoths from different eras, which means you can actually trace how the species changed over time.
Can they really bring mammoths back?
That's the question everyone asks. The company Colossal says they're trying. But honestly, what you'd get would be more like an elephant with some mammoth genes spliced in. The DNA we found could help, but it's not going to resurrect the actual animal that walked the earth.
What surprised the researchers most?
That they found anything at all, I think. They went in looking at squirrel microbiomes. Instead they found this entire preserved ecosystem. And they even found a squirrel itself, frozen in its burrow from who knows how long ago.
Does this change how scientists will look for ancient DNA going forward?
It should. Feces has always been overlooked. But it turns out it's one of the best records we have of what an ancient environment actually contained. Not just one species, but everything that was there.