Carpet of Caribou Droppings Holds Clues to Past

A husband and wife in the Yukon Territory were sheep hunting above treeline in August, 1997, when they smelled something that reminded them of a barnyard. They also noticed the texture of the ground had changed, from hard and rocky to soft and spongy. When the man studied the ground, he realized he was standing ankle-deep in caribou droppings.

The hunter, Gerry Kuzyk, a caribou researcher with the Yukon Department of Natural Resources, knew that no caribou had been seen in the area for decades. He told fellow biologist Don Russell about his unusual discovery in the mountains about 90 miles west of Whitehorse. They returned and noticed that, when viewed from a distance, the snowy mountains were ringed with dark bands of caribou droppings. The bands were being exposed as snow melted from areas where the wind had piled snow for centuries. Recent warming had exposed the stomping grounds of ancient caribou.

When they looked closer at the carpets of manure, Russell found more: a stick that looks like an arrow shaft, a hunting blind made of upturned flat rocks and small stones used to chip tools from other rock.

Russell took a sample of the wood and a few caribou pellets back to Whitehorse, where he works for the Canadian Wildlife Service. The wood, which had been preserved under the snow pack, was carbon-dated to the year 2,350 B.C. It turns out to be the oldest organic example of prehistoric man ever found in Canada. Since the wood predated the bow and arrow by about 2,000 years, Russell said it was probably a throwing dart that was stabilized by bird feathers. The caribou pellets date from 4,000 years old to 2,650 years old.

Those caribou pellets, preserved as if a caribou had dropped them just days ago, hold clues to the past. By breaking apart the nuggets, researchers have determined that the prehistoric caribou were eating sedge plants, which hints at a drier climate. The scientists are also testing the DNA in the manure and caribou bones and antlers found at the site. They want to see if today's caribou are of the same genetic stock as those that lived a few thousand years ago.

The scientists are particularly interested to see if a lot of caribou died about 1,400 years ago, when ash falling from the White River Eruption covered the ground in some areas of the Yukon. Researchers think the blanket of ash was a foot deep, which might have caused a large die-off of caribou if they couldn't adapt.

Since the biologist hunter first recognized the smelly substance in which he stood, Russell and other Yukon scientists have found more than 50 similar sites in southern Yukon Territory. The melting snow patches contain the same mat of caribou pellets, along with preserved birds, small mammals, warble fly larvae and strips of hide that seem to have been used by humans.

Russell said these recent discoveries make him wonder what other obvious scientific finds are waiting to be discovered right under our noses.