Thirteen thousand years ago, bison, deer and elk shared the landscape with American lions, ground sloths, dire wolves and the massive Columbian mammoth — larger, at up to 10 tons, than its arctic relative the woolly mammoth. Then humans arrived in the new world, sharing it for only a few hundred years before many of the species, including the Columbian mammoth, went extinct.
Few topics in archeology are as divisive as whether humans played a role in those extinctions said Robert Kelly, a professor of archeology at the University of Wyoming. Recent discoveries along a creek in Converse County are reinvigorating, and perhaps shedding fresh light on the longstanding debate.
People stumbled on the LaPrele Creek site in 1986, noticing large bones along its banks. George Frison, the esteemed Wyoming archaeologist for which the Frison Institute at the University of Wyoming is named, investigated in the spring of 1987. He found parts of a juvenile mammoth’s spine and ribs, but no head or limbs. He also found about 12 artifacts, mostly flakes from stone tools. One tool he tested for blood protein residue. It returned with a match for elephants. It appeared humans butchered the animal. He didn’t have a chance to further investigate. The site, situated on private land, was closed before he could return.
It sat for 27 years, untouched.
In 2014 new landowners opened the site to the University of Wyoming for summer field schools, where students gain practical field experience working on real archaeological sites.
Todd Surovell, professor of anthropology at the University of Wyoming, director of the George C. Frison Institute of Anthropology, and a field instructor with Kelly, had wanted to see the site since he took the job at the university in 2003.
“What it was like to hunt, kill and feast on an animal of that size, has always been an interest of mine,” Surovell said.
Evidence of human – mammoth interaction is quite rare. There are only about a dozen sites that have earned scientific consensus in demonstrating an absolute link.
Mammoths, which went extinct around 12,700 years ago, and humans shared territory for only a short period of time.
“Mammoth kill sites are iconic, absolutely iconic sites of that time period,” Surovell said.
The first summer the site re-opened for excavation, archaeologists wanted to confirm the juvenile mammoth and humans had been at the creek at the same time. Streams can redeposit bones and artifacts in different locations. Animals die naturally. The mammoth beside LaPrele Creek could have died earlier and the humans happened to use the same spot at a later date, Surovell said.
The excavation found several hundred bone fragments and five small flakes, likely from sharpening butchery tools from the same era. That made it more likely the people and mammoth were at the site at the same time.
Then they found the chopper. The large stone tool was often used for dismembering big animals. Blood protein trapped in the stone tool’s fissures tested as a close match for elephants.
“We’re very confident that humans interacted with this animal,” Surovell said. “In order for this to be accidental, it would have to have been a spectacular scenario.”
What they can’t say definitively is if people killed the animal, or found and scavenged it.
Some scientists believe that the first humans in the new world didn’t know the landscape well enough to hunt. Surovell is in the opposing camp and skeptical of the idea that the new world’s first people were scavengers. These people were the first to inhabit the area. The mammoth, bison, deer and elk wouldn’t have seen humans as predators. They would have been easy prey.
No one has yet found spear points, often left in the ribcage of an animal felled by hunters, but they also only have pieces of the mammoth skeleton, including only part of the ribs, Surovell said.
In summer of 2015 they expanded the excavation and found about 200 artifacts, mostly flakes, but also a fragment of a bone needle. The small needle, about 1 millimeter in diameter, is believed to be the oldest bone needle found in the contiguous United States, Surovell said.
But a needle shouldn’t be at a kill site. It should be at a more permanent campsite, where people lived and sewed.“We don’t really know what to make of it,” Surovell said.
They also found about 300 pieces of red ochre, a natural pigment, usually used at camps for ritual and ceremonies. It had never been found at a place used for butchering an animal.
This summer during the field school, researchers and students will focus on the area they found the chopper and the red ochre. They plan to expand the search area and hope to find more of the skeleton and hopefully some spear points.
While whatever they find might not end the debate on man’s role in the extinction of ice age megafauna, their hunt will likely produce new information on how Paleo Indians lived and hunted.
When the landowners reopened the site to excavation, Kelly thought his students would learn from the field work, but he didn’t expect it to yield new information on early human life, he said. “And I, of course, was totally wrong.”