There’s a lot you can tell about a squirrel from its droppings, even if they’re 700,000 years old.
After collecting ground squirrel droppings preserved in the Yukon permafrost, researchers from McMaster University, the Hakai Institute, and the University of Alberta, among others, have recovered numerous DNA samples from multiple animals, insects, plant species, and microbes.
These findings, published in Nature Communications, are helping to paint a picture of the bygone environment of Beringia, an ancient area famous for the Bering Land Bridge. The droppings span multiple glacial periods and date back to about 30,000 to about 700,000 years ago.
The DNA the research team has extracted from these samples is among the oldest recovered and sequenced.
Read More: 73-Million-Year-Old Teeth Reveal Three New Mammal Species That Lived in the Arctic, Among Dinosaurs
What Is Hiding in Ground Squirrel Droppings?
Ancient Arctic ground squirrel droppings from Lower Quartz Creek, in the Yukon.
(Image Credit: Duane Froese, University of Alberta)
After uncovering the droppings — which look like little pellets, the size of rabbit poo — the research team was able to extract an extraordinary amount of ancient environmental DNA (aeDNA) from the droppings. The team then reassembled over 18 mitochondrial genomes from woolly mammoth, steppe bison, horse, and, of course, ground squirrels.
From the droppings, the team also uncovered evidence of other rodents and even larger predators, such as wolves, big cats — like an American cheetah or a cougar — and over 200 plant groups.
“The research shows us that ground squirrel coprolites, or droppings, preserve remarkably diverse genetic snapshots of ancient Beringia, making them exceptional repositories for understanding evolutionary and ecological change through the deep past,” evolutionary geneticist Hendrik Poinar, one of the study’s senior authors and Director of the McMaster Ancient DNA Centre, said in a press release.
What the Droppings Tell Us About Ancient Ground Squirrels
In addition to identifying genomes and evidence of other flora and fauna from that time, the team uncovered previously unknown genetic diversity in Arctic ground squirrels. One of the lineages even dates back about 700,000 years and has close living relatives in western Siberia.
It was previously believed, based on fossilized ground squirrel remains, that the species that lived then was the same as the one found today in the Yukon; however, the study shows this is not the case. It’s likely that as the climate shifted, some of these animals moved to new regions, demonstrating the impacts a changing climate can have on species.
“We can look at genes under selection due to climate change in the past, and that may help us think about how animals today may, or may not, adapt to our current warming climate,” Poinar said.
How Ground Squirrels Can Help Us Understand the Past
Ground Squirrels, according to the study, are surprisingly helpful in collecting and preserving data that researchers can use to understand the past. The Arctic ground squirrel (Urocitellus parryii), found throughout Beringia (Alaska and the Yukon), has a wide diet and eats anything from plants and fungi to insects, whale meat, rodents, and other carrion.
These eating habits, combined with long-term hibernation, have created the perfect conditions to preserve a biological record of the environment.
“The Arctic ground squirrels that are in the Yukon today act kind of like pack rats,” Tyler Murchie, a Hakai Institute paleogenomics researcher and lead author of the paper, said in the press release. “So they’ll go into the landscape, and they’ll collect a whole bunch of different bits of plant material and bones, seeds, and they’ll bring it back to their burrow.”
From what the researchers can tell, these droppings may help preserve ancient DNA better than bones or permafrost. They hope that the details collected from this research can open doors to more study and more discoveries.
Read More: Revived 40,000-Year-Old Microbes in the Arctic Could Release Greenhouse Gases
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in Nature Communications: Ground squirrel coprolites preserve complex archives of ancient environmental DNA over 700,000 years
