Thousands of years ago, the Clovis people feasted on mammoths. This ancient human group, which featured skilled hunters, roamed the landscapes of the Americas during the last Ice Age. Until now, scientists could only speculate about their dietary habits. A groundbreaking study changes that. Using stable isotope analysis of the Anzick child—an 18-month-old Clovis boy buried in Montana—researchers have now provided direct evidence that Clovis people ate a lot of mammoth meat, complementing it with elk and bison.

This revelation also has a dark side to it. For thousands of years, North America teemed with colossal beasts. Mammoths and mastodons roamed the plains, dire wolves prowled the forests, and giant beavers shaped rivers. Yet, around 12,000 years ago, nearly all of these megafauna vanished.

In this context, this study suggests that humans, not the climate, may have the decisive factor in the extinction of these beasts.

Tracing the Clovis Diet

The researchers, led by James C. Chatters and Ben A. Potter, analyzed bone collagen isotopes from the Anzick child. His remains were discovered on a Montana ranch in 1968 and later reburied in 2014. Before reburial, scientists analyzed the chemical composition of his bones.

These isotopes act as chemical fingerprints, revealing what the child’s mother ate and passed on through breastfeeding. Intriguingly, mammoth meat accounted for more than 40% of his family’s diet. Elk or bison made up another substantial portion, while smaller animals barely featured.

Their findings upended previous assumptions of the Clovis people as generalist foragers. Instead, they appeared to be specialists, focusing on megafauna like the Columbian mammoth. This contrasts with the broad-spectrum diet of modern hunter-gatherers, who rely heavily on smaller game and plants.

“Our findings are consistent with the Clovis megafaunal specialist model, using sophisticated technology and high residential mobility to subsist on the highest-ranked prey,” the study reports.

Munching on mammoths

These enormous creatures offered a significant return on effort—high-calorie meat and fat that could sustain a group through harsh winters. The Clovis also had the tools for the job: fluted spear points ideal for bringing down massive prey. Feasting on mammoths likely supported the rapid expansion of the Clovis across the Americas, just as they encountered pristine environments rich in megafauna.

But did these people eat mammoths into extinction?

By 12,000 years ago, mammoths and other Ice Age giants disappeared, victims of climate change, overhunting, or a combination of both. For decades, scientists blamed the disappearance of megafauna on a changing climate. The last ice age ended abruptly, causing rapid warming and ecological upheaval. Yet, North America’s megafauna had survived previous cycles of warming and cooling. Why was this one different? Humans could be the missing puzzle piece.

The right time for extinction

The Clovis people, with their finely crafted stone spearheads, appeared on the continent just as the glaciers were retreating. Mammoths were already in trouble, and humans may have been the last straw.

According to the overkill hypothesis, these early Americans hunted naïve animals—unfamiliar with human predators—at unsustainable rates, driving them to extinction.

This hypothesis still isn’t completely proven, but the Anzick burial offers some convincing evidence. It’s a rare glimpse into a culture that left no written records but whose impact is etched into the earth, into other species, and, as it turns out, in isotopes as well.

The findings appeared in the journal Science Advances.