Ground squirrels spend several months in a winter sleep, then wake up hungry and eat everything in sight. A study of 700,000-year-old DNA from coprolites – fossilized poop – has revealed that when ancient relatives of ground squirrels (Urocitellus sp.) Upon awakening, they ate a diverse diet of plants, insects, and the carcasses of megafauna, including woolly mammoths, bison, and big cats.
The DNA sequences, reported in a June 9 press release Natural communications study, reveal a previously unknown ground squirrel lineage and, potentially, the oldest mammoth DNA in North America.
There are 13 species of ground squirrels in the genus Urocitellusand they are found primarily in northwest North America and Asia. Ground squirrels get their name from their earthen burrows, where they can spend up to eight months a year in a state of hibernation called torpor.
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When they emerge, “they’re desperate for protein and high-quality food,” says Bryan McLean, an evolutionary biologist at the University of North Carolina at Greensboro. “I have seen them eat road-killed individuals of the same species.”
In the Klondike region of Canada’s Yukon Territory, gold mining practices that dissolve permafrost deposits using water jets have also uncovered ancient ground squirrel burrows filled with coprolites.
Tyler Murchie, a biomolecular archaeologist at the Hakai Institute in Heriot Bay, Canada, and his colleagues wondered whether coprolites would serve as a genetic archive of past ecosystems – through the lens of ground squirrel diets.
The coprolites have been dated to between about 700,000 and 17,000 years ago, during a geological period, known as the Pleistocene, punctuated by ice ages, and when mammoths, bison, horses and other megafauna roamed North America.
Yet Murchie was initially astonished when mitochondrial DNA sequences from this “ice age” appeared in the coprolites – as did sequences from rodents, bats and birds; invertebrates, including parasitic worms; and plants such as grasses and sedges. The DNA of big cats belonged to either the North American cheetah (Miracinonyx on the drum), suspects Murchie, or to mountain lions (Puma to color).
“You can imagine these squirrels emerging from the ground and starting to eat carcasses lying in the environment,” says Mikkel Pedersen, a molecular paleoecologist at the University of Copenhagen. “They are Pleistocene zombies.”
The authors dated the oldest coprolites using volcanic ash deposits found directly above the samples. If these age estimates are accurate, the 700,000-year-old DNA sequences from mammoths and other samples would be among the oldest ever recorded for any organism, says Pedersen, who peer-reviewed the manuscript. “Most evidence points to this being a set of coprolites that could be 700,000 years old,” Pedersen says.
Ancient DNA – including around twenty complete mitochondrial genomes – has revealed big surprises. Remains of Ice Age squirrels originally identified as Arctic ground squirrels (Urocitellus parryii) – similar to those found today in the Yukon – rather belonged to a previously unknown lineage of the long-tailed ground squirrel Urocitellus undulatusa species found today in Siberia, Mongolia, China and Kazakhstan.
Murchie says an upcoming unpublished paper, focusing on gigantic sequences, will reveal further storylines. He hopes other ancient DNA researchers will consider ground squirrel scats as an untapped paleo-archive that can be used alongside more conventional resources such as bones and sediments. McLean says he would love to get DNA from ground squirrel droppings found at lower latitudes, not just in permafrost. “We also need coprolites in other parts of the chain.”
This article is reproduced with permission and has been published for the first time June 9, 2026.
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