Discovering ancient bones near McGrath. The water level in the Kuskokwim River rises and falls in response to snowmelt and rain. High water plucks trees from the muddy riverbanks, transporting them down the river. Low water strands jumbles of wood on sandbars. These wood piles are welcome to the river communities because the logs are a convenient source of firewood.
I was six years old when we set out from McGrath to collect firewood. Francis, my stepdad, drove the boat upriver, so that the collected logs could then be floated downriver. Our strategy was to tie a raft of logs to the bow of the boat and gently motor the raft back to town.
While my mom and Francis were sawing wood for the raft, I played games with my older brother Burke—setting up sticks for target practice with rocks or a BB gun. Burke recalls that one of the sticks sounded different from the others, drum-like. We broke the stick and showed the sponge-like internal texture to our parents, who identified it as a bone. We abandoned the stick games to search for bones.
We found more bones—a jaw, a rib, and then the real prize—a large bone later identified as a femur. Burke raised the 20-inch bone over his head and hollered, “MASTODON!!!”
It might seem like a trivial distinction, but as the younger brother, I feel obligated to point out that Burke was wrong. Mastodons did live in Alaska, but because they were forest dwellers (eating wood and branches), they are poorly preserved in the fossil record. Mammoth fossils are more common because mammoths ate grasses, and gentle sediment deposition in grassy plains helped to preserve their remains. This femur was from a small mammoth.
Mammoths migrated over the Bering Land Bridge to roam across Alaska’s grassy steppes. They reached heights of 11 feet at the shoulder and weighed up to 12,000 pounds. Mammoths ate 200 pounds of grasses and sedges per day. Their long hair (up to three feet) insulated them from the cold, and their small ears and tails helped limit heat loss. We know a lot about mammoths because they are one of the best-preserved prehistoric animals, including frozen remains with intact muscle, hair, and stomach contents. A frozen mammoth in Siberia began to bleed during its excavation.
Alaska’s mammoths went extinct around 10,000 years ago, except for an isolated population that survived another 5,000 years on St. Paul Island. The killer was climate change. As the Ice Age ended, wet conditions converted the grassy steppes into peat (decomposed plant material), which choked out grass and sedge root systems. To make matters worse, rising seas (due to ice melt) flooded the Bering Land Bridge, preventing animals from migrating back to Siberia. Not all the steppe dwellers went extinct—caribou and musk ox have large feet compared to their mass, which allowed them to travel greater distances over the peat. Mammoths, with relatively small feet, weren’t so lucky. Mammoths were joined in extinction by horses and bison.
Our femur discovery felt special but finding mammoth bones near McGrath isn’t that unusual. In elementary school, the Edwards family across the street found two tusks when the kids were sliding down the riverbank. In 1982, two mammoths were discovered at the Rosander’s mine on Colorado Creek, 45 miles from McGrath. I suppose it’s unrealistic, but I wish Donovan, the mine owner’s grandson, had brought mammoth bones to show-and-tell instead of those gold nuggets.
Most rural Alaskans spend their time outside to bring something useful home, like firewood, meat, or fur. But I appreciate the impractical treasures too. Finding mammoth bones as a child trained me to scan riverbanks and comb beaches as an adult. This habit isn’t limited to Alaska. After all, mammoths migrated as far as Central America and Florida—you never know where you might find one.
(Note: Regional history and photographs were provided by the Sally Jo Collins Museum and Tochak Historical Society, PO Box 236, McGrath, Alaska. A collection of mammoth fossils is available for viewing at the museum.)
Luc Mehl is a renowned adventurer with a deep love of wild country. Luc’s website, www.thingstolucat.com, offers write-ups of his adventures and educational resources for backcountry safety and travel.