Ancient squirrel droppings reveal Ice Age ecosystems in Yukon

Scientists have used DNA preserved in frozen Arctic ground squirrel feces from Yukon burrows to reconstruct ecosystems that existed during the last ice age. The material, some of it as old as 700,000 years, contained traces from mammoths, horses, bison, wolves, birds, bats, insects, fungi, microbes and hundreds of plants. Researchers say the buried burrow chambers acted like natural archives, preserving a detailed record of what the squirrels ate and what lived around them. The study suggests that the mammothsteppe environment in eastern Beringia remained relatively stable for hundreds of thousands of years, even as it differed sharply from the wetter boreal landscape found there today. The findings also matter for climate research. Scientists say the rapidly warming Arctic is thawing these permafrost sites, which means valuable records of past ecosystems may disappear before they can be studied further.