Scientists have uncovered the first direct evidence that ancient Americans relied primarily on mammoth and other large animals for food. Their research sheds new light on both the rapid expansion of humans throughout the Americas and the extinction of large ice age mammals.
The study, featured on the Dec. 4 cover of the journal Science Advances , used stable isotope analysis to model the diet of the mother of an infant discovered at a 13,000-year-old Clovis burial site in Montana. Before this study, prehistoric diet was inferred by analyzing secondary evidence, such as stone tools or the preserved remains of prey animals.
The findings support the hypothesis that Clovis people specialized in hunting large animals rather than primarily foraging for smaller animals and plants.
The Clovis people inhabited North America around 13,000 years ago. During that time period, animals like mammoths lived across both northern Asia and the Americas. They migrated long distances, which made them a reliable fat- and protein-rich resource for highly mobile humans.
"The focus on mammoths helps explain how Clovis people could spread throughout North America and into South America in just a few hundred years," said co-lead author James Chatters of McMaster University.
"What's striking to me is that this confirms a lot of data from other sites. For example, the animal parts left at Clovis sites are dominated by megafauna, and the projectile points are large, affixed to darts, which were efficient distance weapons," said co-lead author Ben Potter, an archaeology professor at the University of Alaska Fairbanks.
Hunting mammoths provided a flexible way of life, Potter said. It allowed the Clovis people to move into new areas without having to rely on smaller, localized game, which could vary significantly from one region to the next.
"This mobility aligns with what we see in Clovis technology and settlement patterns," Potter said. "They were highly mobile. They transported resources like toolstone over hundreds of miles."
Researchers were able to model the Clovis people's diet by first analyzing isotopic data published during earlier studies by other researchers of the remains of Anzick-1 , an 18-month-old Clovis child. By adjusting for nursing, they were able to estimate values for his mother's diet.
"Isotopes provide a chemical fingerprint of a consumer's diet and can be compared with those from potential diet items to estimate the proportional contribution of different diet items," said Mat Wooller, an author on the study and director of the Alaska Stable Isotope facility at UAF.
The team compared the mother's stable isotopic fingerprint to those from a wide variety of food sources from the same time period and region. They found that about 40% of her diet came from mammoth, with other large animals like elk and bison making up the rest. Small mammals, sometimes thought to have been an important food source, played a very minor role in her diet.
Finally, the scientists compared the mother's diet to those of other omnivores and carnivores from the same time period, including American lions, bears and wolves. The mother's diet was most similar to that of the scimitar cat, a mammoth specialist.
Findings also suggest that early humans may have contributed to the extinction of large ice age animals, especially as environmental changes reduced their habitats.
"If the climate is changing in a way that reduces the suitable habitat for some of these megafauna, then it makes them potentially more susceptible to human predation. These people were very effective hunters," said Potter.
"You had the combination of a highly sophisticated hunting culture — with skills honed over 10,000 years in Eurasia — meeting naïve populations of megafauna under environmental stress," said Chatters.
An important aspect of this research, according to Potter and Chatters, is their outreach to Native Americans in Montana and Wyoming about their concerns and interest in this work.
"It is important and ethical to consult with Indigenous peoples on questions relating to their heritage," they said.
They worked with Shane Doyle, executive director of Yellowstone Peoples, who reached out to numerous tribal government representatives throughout Montana, Wyoming and Idaho. "The response has been one of appreciative consideration and inclusion," said Doyle.
"I congratulate the team for their astounding discovery about the lifeways of Clovis-era Native people and thank them for being tribally inclusive and respectful throughout their research," he said. "This study reshapes our understanding of how Indigenous people across America thrived by hunting one of the most dangerous and dominant animals of the day, the mammoth."
Other authors of the paper include Stuart J. Fiedel, independent researcher; Juliet E. Morrow, University of Arkansas; and Christopher N. Jass, Royal Alberta Museum.
