McMaster researchers trace arctic evolution in squirrel droppings CHCH Ground squirrel coprolites preserve complex archives of ancient environmental DNA over 700,000 years Nature Squirrel poop dating back to last ice age is full of mammoth, horse DNA CBC Squirrel droppings yield a goldmine of prehistoric DNA The Globe and Mail A Surprising Find in Ancient Squirrel Poop: Woolly Mammoth Meat The New York Times