Mammoth Prospecting

Natural History, Dec, 1998 by Clare Flemming

On August 3, our team of researchers led by Ross MacPhee, chairman of the Museum's Department of Mammalogy, departed from the Siberian mainland in a huge Russian helicopter bound for Wrangel Island. Joined by Jeff Saunders, of the Illinois State Museum, and our Russian colleagues Alexei Tikhonov and Sergey Vartanyan, we spent the next eighteen days on this 2,000-square-mile island, well north of the Arctic Circle. Our goal? To test a new idea about what may have caused the catastrophic extinctions of mammals at the end of the last ice age. Unconvinced by theories that these extinctions were the result of climate change or overhunting, Ross and virologist Preston Marx, of the Aaron Diamond AIDS Research Center, had come up with the hyperdisease hypothesis: as human populations expanded and colonized new landmasses during the Pleistocene, they brought with them virulent pathogens that wiped out native animals.

Where could we go to test this hypothesis? We picked Wrangel Island because woolly mammoths had survived there longer than anywhere else on earth. Whereas all other Mammuthus primigenius had become extinct by 10,000 years ago, the population on Wrangel persisted an additional 6,000 years. In other words, these mammoths roamed the tundra while Pharaoh Sesostris I was building his shrines at Thebes more than 3,500 years ago. Because Wrangel's mammoths were such late survivors, we thought that if a deadly virus could be detected, their fossil remains would be the likeliest to have retained traces of it.

Getting to Wrangel was not easy--after flying from New York to Saint Petersburg and taking a series of trains and buses to a military base in a Moscow suburb, we boarded an Ilyushin turboprop for a ten-hour flight to the Siberian coastal settlement of Mys Shmidta, a hundred sea miles south of our goal. Our six days of traveling spanned sixteen time zones. A local jailbreak and an ensuing rash of murders in Mys Shmidta kept us there another four days before a helicopter could take us to the island.

Once on Wrangel, we took an excruciating four-hour truck ride up riverbeds and made camp on the north side of the island in an eight-by-seventeen-foot cabin that sheltered the five of us, all our gear, all our food, and all the fossils we would collect. Outside our door, miles and miles of soggy, beautiful, lonely tundra stretched to the horizon. The only breaks in the landscape were the island's snow-covered mountains to the south and an occasional musk ox or an arctic fox.

Working on Wrangel was quite unlike any fieldwork I have ever done. Mammoth tusks and molars were abundant and found almost exclusively in the small rivers that drain the tundra's waters to the Arctic Sea. We spent our days in hip waders prospecting the rivers, peering through the crystalline waters and looking for specimens. Excited by our discoveries, we would ignore the fact that the water was barely above freezing and plunge our arms in again and again to claim the fossil rewards. Despite the twenty-four hours of daylight, none of us had trouble sleeping, thanks to trudging miles over the tundra and lugging heavy specimens in weather that included half-hour cycles of gale-force winds, driving rain, bursts of sun, low fog, and snow. At night, after a meal of pasta or potatoes and reindeer, we crowded around our little table and listened while Sergey made his 10:00 p.m. radio contact with the outside world. Ross would then announce the next day's plan. Since we had not received the all-terrain vehicle promised us, every move we made was on foot. One centimeter on our map equaled one kilometer, so I would cringe as Ross opened the calipers ever wider. "Okay," he would say, "tomorrow we'll walk eight miles to the lower Naskhok River. That should take about four hours. Then we can start prospecting upstream."

We collected many teeth and tusks, but Ross practically tripped over the best find of all--the only mammoth ulna (a forelimb bone) ever found on Wrangel. Incredibly, the bone oozed grease, as though the animal had been freshly killed. But what about deadly pathogens? We drilled the ulna and other mammoth bones to extract cores for radiocarbon dating and molecular analysis. Postdoctoral fellow Alex Greenwood is now working on the cores in the Museum's laboratories, searching for an ancient signal that might tell us if the hyperdisease hypothesis can be verified.

Clare Flemming is the laboratory and special collections supervisor in the Museum's Department of Mammalogy. To learn more about the project, see the Museum's Web site (www.amnh.org/science/expeditions/siberia/).