Science tells us that the grandest Western adventure was undoubtedly the earliest one, when Ice Age people first showed up on the North and South American continents, the largest uninhabited region humans would ever explore on Earth—a wilderness about five times the area of Australia. These new lands were uninhabited by humans but teeming with gigantic and fierce animals, many capable of killing and eating human beings. We know next to nothing of these people, and the epoch in which they lived, except that they were hunters exploring a brand-new land, crossing glaciers, braving raging rivers, encountering never-before-seen huge creatures, and surviving.
The late Pleistocene megafauna included huge pack-hunting lions, saber-toothed cats, dire wolves, and gigantic short-faced bears that fed on horses, camels, mammoths, and other abundant prey species that roamed the land. The first Americans lived with these predators and sometimes competed with them. Amazingly, many of the megafauna encountered by these pioneering humans were extinct by around 12,700 years ago, just before the end of the Pleistocene epoch.
This article appears in Issue 34 of Alta Journal.
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Yet, while we know when the megafauna disappeared from North America, we may only have thought we knew when these Ice Age people appeared. This process of “knowing” and then being proved wrong is the wonder of science. For much of the 20th century, archaeologists had evidence that pointed to Clovis hunters being the original colonists of North America, having shown up south of the ice about 13,200 years ago. They were highly mobile and are believed to have traversed the continent from its northernmost reaches (a section of the Bering Land Bridge) southward into the present-day Lower 48 states along an ice-free corridor between vast continental glaciers. Within a few hundred years, the Clovis people had left their distinctive fluted spearpoints all over North America.
They hunted and ate mammoths, as documented by the faunal remains and tool assemblages at around a dozen of these kill sites across western North America, together with the analytical results from human skeletal remains recovered in Montana. But as quickly as they appeared, the Clovis people disappeared from the scene along with some 33 genera of megafauna, about half of which died off within a tiny window of about 500 years—roughly between 13,200 and 12,700 years ago. An “overkill” hypothesis places the blame on Clovis hunters, aided by climate change. The larger message is that, perhaps for the first time since emerging from Africa, modern humans may have participated in a major, sudden extinction event.
In the past few years, however, new evidence has been found to suggest that humans were present in North America before the Clovis people. Tools discovered in 2019 at a site on the Salmon River in Idaho, for example, are about 16,000 years old, according to radiocarbon dating that is considered reliable. Because the ice-free corridor south from the Bering Land Bridge was probably not open until after 15,000 years ago, the initial migration of people into the Americas may have been down the icy Pacific coast. These earlier colonists are sometimes called pre-Clovis, and very little is known of their daily lives. No credible estimates are available for the size or range of any pre-Clovis population, but perhaps they were merely a few hunter-gatherers occupying limited ranges who did not survive to greet the Clovis mammoth hunters thousands of years later.
As for the earliest accepted presence of the pre-Clovis colonists, 16,000 years ago was about it. But in 2009, ancient human fossilized footprints were found in what is now White Sands National Park, in southern New Mexico; in 2019, seeds from the aquatic plant Ruppia cirrhosa were found in apparent association with the footprints and were later radiocarbon-dated and calibrated to calendar dates between 21,130 and 22,860 years ago. These seeds were discovered above, below, and within the footprints. The 60-some footprints were located near the shore of ancient, mostly dried-up Lake Otero, with tracks from now-extinct megafauna herbivores such as Columbian mammoths and Harlan’s ground sloths and Pleistocene predators like dire wolves and American lions. Some archaeologists estimate that there are thousands of other human tracks to be found. A National Park Service report states that the “fossilized footprints of White Sands are probably the most important resources in the Americas to understand the interaction of humans and extinct animals from the ice age.”
The dates for the human footprints, if correct, would be remarkable because they would place the footprint makers in New Mexico near the peak of the Last Glacial Maximum, a geological epoch that lasted from about 29,000 to 19,000 years back, a time of severe cold conditions when glacial ice was at its maximum and sea levels were about 400 feet lower than at present because water had been caught up in the continental ice sheets. The climate in the region around the White Sands site was less arid, and extensive grasslands surrounded Lake Otero.
The 7,000-year gap between 16,000 and 23,000 years ago (I’m rounding up) is significant. And the idea that people might have left footprints or other cultural material in North America earlier than 16,000 years ago is a relatively new—and contested—subject of scientific study. So the claim of great antiquity for the White Sands fossil footprints was destined to be challenged by archaeologists—and it has been. At issue are hard-water contamination of the dated carbon sample and the possibility of the buoyant Ruppia seeds having been redeposited.
Arguments to support the validity of the footprint dating are enthusiastically championed in peer-reviewed journals by the NPS and its partners at the U.S. Geological Survey’s Denver office and the U.K.’s Bournemouth University. The team released an uncompromising statement, concluding “that the geochronology of WHSA Locality 2 is indeed resolved and that humans were present in North America during the Last Glacial Maximum.”
Equally vocal in peer-reviewed journals are the critics of this claim. They contend that questions remain about the formation processes at WHSA Locality 2 (the official name for the White Sands footprint site), the ecology of the Ruppia plants, and hence the geochronology of the footprints. In the Journal of Archaeological Science, Dave Rachal and Robert Dello-Russo write, “We argue that the claim for a Last Glacial Maximum age for the human tracks at WHSA-2 is flawed, and that further chronometric research at the [site] is needed.”
If the older dates are valid, then the first Americans coexisted with the late Pleistocene megafauna for much longer than previously believed, during which time they did not drive the animals to extinction.
Beyond these arguments, it is worth noting that the White Sands site lacks the usual archaeological associations and corroborations—no artifacts, campsites, or datable hearths. And given the lack of uncontested evidence of humans elsewhere in the Americas from 16,000 to 23,000 years ago, the claim of great antiquity at White Sands still demands extraordinary proof. In time, future fieldwork could yield additional datable materials to resolve the debate, but so far, the NPS has not had independent archaeological teams investigate the footprint location.
The NPS’s failure to encourage independent confirmation of its conclusions is possibly thwarting the potential discovery of what may lie buried in those desert sands, finds that would inform us about the relationship between Ice Age megafauna and humans. Normally, theories are proposed, challenged, and either affirmed or disproved after new evidence comes to light. It is a very bad time to dismiss science. And more than the age of Ruppia seeds may be at stake.
Are humans, as the overkill hypothesis suggests, murderous brutes with insatiable appetites for more, more, more? Or are we the deeply sentient beings we sometimes suspect ourselves to be, capable of tolerance, generosity, and empathy? The answer will determine how we deal with today’s most urgent crisis: climate change.•
Author, disabled veteran, filmmaker, and naturalist Doug Peacock is the founder and president of Save the Yellowstone Grizzly. Peacock was a Green Beret medic in Vietnam and the real-life model for Edward Abbey’s George Washington Hayduke in The Monkey Wrench Gang.
