Space & Science

New Mexico mammoths among the best evidence of early humans in North America

New Mexico mammoths among the best evidence of early humans in North America

The remains of two mammoths discovered in New Mexico show that humans lived in North America much earlier than expected. Credit: NPS.

About 37,000 years ago, a mammoth mother and her calf perished at the hands of humans.

The bones from the butchery site record how humans shaped pieces of their long bones into disposable blades to break down their carcasses and melted their fat over a fire. But one key detail sets this site apart from others from that era. It’s in New Mexico, a place where most archaeological evidence only places humans tens of thousands of years later.

A recent study by scientists at the University of Texas at Austin reveals that the site offers some of the most conclusive evidence that humans settled in North America much earlier than previously thought.

Researchers have revealed a wealth of rarely found evidence in one place. It includes fossils with blunt fractures, bone splinter knives with worn edges, and signs of controlled fire. And thanks to the carbon dating analysis on the collagen extracted from the mammoth bonethe site also has a sedentary age of 36,250–38,900 years, making it one of the oldest known sites left by ancient humans in North America.

“What we have is amazing,” said lead author Timothy Rowe, a paleontologist and professor at UT Jackson School of Geosciences. “It’s not a charismatic site with a beautiful skeleton laid out on the side. Everything is destroyed. But that’s what it’s all about.”

Credit: University of Texas at Austin

The findings were published in Frontiers in Ecology and Evolution.

Rowe does not generally research mammoths or humans. He got involved because the bones appeared in his garden, literally. A neighbor spotted a weathered defense of a slope on Rowe’s property in New Mexico in 2013. When Rowe went to investigate, he found a sunken mammoth skull and other bones that appeared to be deliberately broken. It was apparently a butcher shop. But the earliest presumed human sites are shrouded in uncertainty. It can be notoriously difficult to determine what has been shaped by nature versus human hands.

This uncertainty has led to debate in the anthropological community about when humans first arrived in North America. The Clovis culture, which dates back 16,000 years, left behind elaborate stone tools. But on older sites where stone tools are absent, the evidence becomes more subjective, said Mike Collins, a retired Texas State University professor who was not involved in this paper and who oversaw the research at Gault, a Archeological site near Austin with an abundance of Clovis and pre-Clovis artifacts.

New Mexico mammoths among the best evidence of early humans in North America

Close-up of the pile of bones during excavation. This random mix of ribs, broken skull bones, a molar, bone fragments and stone pebbles is a heap of trash from slaughtered mammoths. It was kept under the skull and tusks of the adult mammoth. Credit: Timothy Rowe/University of Texas at Austin.

Although the mammoth site lacks any clearly associated stone tools, Rowe and his co-authors uncovered an array of supporting evidence by subjecting samples from the site to scientific laboratory analysis.

Among other findings, CT scans performed by the University of Texas High-Resolution X-Ray Computed Tomography Facility revealed bone flakes with microscopic fracture networks similar to those of freshly trimmed cow bones and wounds well-placed perforators that would have helped drain fat from ribs and vertebral bones.

“There are really only a few effective ways to skin a cat, so to speak,” Rowe said. “The butchery bosses are quite characteristic.”

Additionally, chemical analysis of the sediments surrounding the bones showed that the fire particles came from a sustained and controlled burn, not from a lightning strike or wildfire. The material also contained pulverized bone and the burnt remains of small animals— mainly fish (even though the site is more than 200 feet above the nearest river), but also birds, rodents and lizards.

  • New Mexico mammoths among the best evidence of early humans in North America

    The excavation site contains mostly broken bones from the ribs and spine of mammoths. The most important fossil is part of the skull of the adult mammoth. Credit: Timothy Rowe/University of Texas at Austin.

  • New Mexico mammoths among the best evidence of early humans in North America

    Butchery marks on mammoth ribs. The upper rib shows a fracture due to a blunt impact; the middle rib shows a puncture wound, probably made by a tool; lower rib has hash marks. Credit: Timothy Rowe et al. / The University of Texas at Austin.

Based on genetic evidence indigenous populations of South and Central America and artifacts from other archaeological sites, some scientists have proposed that North America had at least two founding populations: the Clovis and a pre-Clovis society with a lineage different genetics.

The researchers suggest that the New Mexico site, with its age and bone tools instead of elaborate stone technology, may lend support to this theory. Collins said the study adds to a growing body of evidence for pre-Clovis societies in North America while providing a toolkit that can help others find evidence that might have otherwise been overlooked.

“Tim has done excellent and thorough work that represents cutting edge research,” Collins said. “It’s about forging a path that others can learn from and follow.”

Research on the Gault site pushes back the date of the first North Americans

More information:
Timothy B. Rowe et al, Human occupation of the North American Colorado Plateau ∼37,000 years ago, Frontiers in Ecology and Evolution (2022). DOI: 10.3389/fevo.2022.903795

Quote: New Mexico mammoths among best evidence of early humans in North America (2022, August 1) Retrieved August 1, 2022 from early-humans.html

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