How Ice Age Hunters Chased Giant Prey Across the Americas

For many years, archaeologists have maintained that the earliest people to move through the Americas lived off whatever was available in each unfamiliar environment, including small animals, fish and edible vegetation.

New research comes to the reverse conclusion. It finds that Ice Age hunters concentrated overwhelmingly on mammoths and other enormous plant-eaters.

As they expanded swiftly from Alaska to the far south of South America, they appear to have maintained this same specialised approach to hunting across both continents.

The results indicate that targeting vast prey, rather than adjusting to every new ecosystem, may have enabled one of the fastest human migrations in history.

They also reopen the longstanding argument that human hunters contributed to the extinction of many of these huge animals.

Reassessing the diet of the first Americans

For decades, archaeologists have been divided over the food eaten by the first Americans.

One group has argued that they were specialists in large game, deliberately pursuing major herbivores.

The opposing view has been that they were generalists, using all resources an ecosystem provided, from rabbits, birds and fish to plants.

Ben Potter, an archaeologist at the University of Alaska Fairbanks (UAF), and James Chatters of McMaster University set out to assess both explanations using the same evidence base.

Evidence from cultures spanning the continents

The researchers assembled records of animal bones from the three earliest cultures found across the Americas.

Together, these cultures extended across the full length of the hemisphere. The oldest sites were in Beringia, the former landmass linking Alaska with Siberia.

They were followed by the Clovis people of North America, recognised by their characteristic fluted stone spear points.

After them came the makers of South America’s Fishtail points, whose spear tips featured a wide, flared base like a fish’s tail.

Giant animals dominated the Ice Age hunters’ diet

The team gathered 50 sites containing well-preserved animal remains: eight from Beringia, 25 from North America and 17 from South America.

At 49 of the 50 locations, the bones of large animals represented most of the edible meat. Just one site appeared to reflect genuinely generalist foraging.

Within this large-animal group, megaherbivores were especially distinct. These animals weighed more than 1 tonne.

Woolly mammoths were the principal food source in Beringia, Columbian mammoths formed the basis of the Clovis diet, while giant ground sloths and gomphotheres-distant elephant relatives-were predominant in South America.

Measured by the weight of food that could be obtained, the pattern is clear. Across every region, animals weighing more than 1 tonne provided approximately 83 to 88 percent of the calories that early people could have acquired from prey.

Small animals scarcely featured, supplying far below one percent.

Could evidence of small prey have disappeared?

Critics have long raised an obvious concern: small bones preserve badly and may simply have vanished from ancient sites.

To test this possibility, the researchers increased the small-game figures one hundredfold before recalculating the results. Even then, large animals supplied more than 98 percent of the food at Clovis sites.

The bone evidence is supported by direct findings. In 2024, researchers analysed the chemistry of the bones of the only known Clovis individual-an 18-month-old child from Montana-to reconstruct his mother’s diet.

Their analysis indicated that mammoths and other giants accounted for roughly 96 percent of her protein, with small mammals contributing about 4 percent.

Weapons and tools for large prey

The artefacts support the same conclusion as the bones. In all three regions, toolkits focused on hunting and processing large animals, with large stone spear points, blades and hide scrapers among their key items.

Hunters used an atlatl, a spear-thrower, to drive darts deep into the bodies of thick-skinned prey.

Equally revealing is what has never been found at these sites.

There are no grinding stones for preparing seeds or earth ovens for cooking plants. Nor have archaeologists found fishhooks, harpoons or net sinkers.

Signs of extensive planning

The stone tools also point to deliberate preparation.

Spear points were repeatedly resharpened until they became too short for use, while toolmakers transported high-quality stone remarkably far from where it originated.

Across the central Great Plains, complete toolkits travelled up to 595 km, and one piece came from roughly 1,500 km away.

Carrying such quantities of stone would only make sense for highly mobile people planning ahead for prey they expected to encounter wherever they travelled.

By contrast, generalists operating within a small home range would have had little incentive to accumulate equipment sourced from such great distances.

Tracking giants through the Americas

Pursuing giant animals proved to be a strategy that worked across diverse places. Mammoths and ground sloths occupied vast ranges and a wide variety of habitats.

Hunters familiar with their behaviour could pass from tundra to grassland and then tropical savanna while continuing to find prey they understood. Their expertise remained useful.

The authors argue that this is how people traversed two continents within a few hundred years. Clovis points occur from Alberta to Venezuela over perhaps 300 to 600 years, accompanied throughout by almost identical toolkits.

Generalists, meanwhile, would have required generations to understand the plants and small animals of every newly encountered ecosystem.

Southern hunters changed species, not strategy

South of Panama, the prey changed but the principle remained the same. When mammoths were replaced by giant ground sloths and gomphotheres, hunters in the south shifted their attention to those new giants.

A 2025 study of southern South America concluded that extinct megafauna were the leading prey there before around 11,600 years ago, after researchers stopped combining older and younger sites in the same analysis.

Potter and his colleagues characterise these populations as dietary specialists but habitat generalists. Their food choices remained narrowly focused despite complete changes in the landscapes around them.

Their expertise lay not in mastering a single location, but in mastering a particular kind of animal.

A potential link to extinction

This concentration on huge prey may also have had a more troubling consequence. In every region, the favoured giants disappeared soon after humans arrived and shared their environments.

Woolly mammoths were gone by approximately 13,400 years ago, Columbian mammoths by 12,800 years ago, and South American megafauna by around 11,600 years ago.

A 2021 study directly linked the extinctions in South America to the spread of Fishtail points and growing human populations.

Throughout the hemisphere, the researchers identified evidence of human hunting for 28 of the 41 genera of large mammals that became extinct. That represents most of them.

Many of these animals were keystone species, whose grazing and trampling reshaped entire landscapes; losing only a small number could therefore affect whole food webs.

It remains unresolved whether hunting alone caused the deaths, as the climate was also transforming these environments at the time.

The authors do not argue that humans were the only cause. Instead, they contend that the evidence makes it difficult to exclude human pressure.

Ice Age hunters adapted to prey

What happened afterwards makes the contrast clearer. After the giants vanished, the previously uniform cultures split into regional traditions adapted to local game.

Bison hunters became dominant on the Plains during the Ice Age, caribou hunters spread across the North-east, and South American hunters used smaller spear points to pursue guanaco and deer.

In other words, the specialists eventually became the generalists that many researchers had always assumed they were.

For a discipline that has debated the specialist-versus-generalist question for half a century, the scope of this new study reframes the discussion.

It brings Beringia, North America and South America into a single coherent narrative, while combining bone evidence with direct chemical evidence from a real individual.

The more difficult question is now not what these people ate, but how far their appetite for giants reshaped the living world through which they travelled.