Scotty MacNeish's Pendejo Cave

The Earliest Arrivals

"Pendejo Cave," archaeologist R. S. "Scotty" MacNeish called it. Located in south central New Mexico in the desert basin between the Sacramento and Guadalupe Mountain ranges to the east and the Organ Mountain range to the west, Pendejo (Spanish vernacular for "coward" or "jerk") Cave doesn’t look like much.

Map of area where Pendejo Cave is located

It lies recessed into a 40-foot thick limestone stratum near the top of the south side of an isolated and rugged drainage called by the appropriate name of "Rough Canyon." It overlooks a talus slope covered with typical Chihuahuan Desert vegetation: creosote bush, mesquite, prickly pears, cane cholla, acacia and various hedgehog cacti. Its mouth, open to the north winds of winter, spans perhaps 15 or 16 feet in width and some 25 feet in height. Its depth runs maybe 35 or 40 feet, narrowing like a funnel through rough and tumbling limestone floor, ceiling and walls.

Pendejo Cave

After a visit to the cave with MacNeish in the early 1990s, my wife, Martha, and I, could scarcely imagine why he, of all people, would have chosen such a place for excavation. MacNeish (killed at 82 years of age in a car crash in Belize on January 17, 2001) stood at the pinnacle of his profession, a legend in American archaeology.



"Wait until we get back to the lab and you see what we’ve found," Scotty said.

If what MacNeish and his team discovered during excavations from 1990 to 1993 in Pendejo Cave weathers the storm of controversy it has raised in American archaeology, it will help change fundamental beliefs about when man first appeared in the Southwest and, in fact, in the Americas. It includes not only extinct animal remains, basketry, a pendant, apparent crude stone and bone tools and possibly even human hair, but astonishingly, clay-lined fire pits with apparent human finger and palm prints still impressed in the hardened clay. From the stratigraphy of the artifactual deposits, MacNeish’s team learned that prehistoric peoples had evidently occupied Pendejo Cave at various times over the millennia, the last time, about 13,000 years ago, the first time, a mind-bending 50,000 years ago. This means, if a skeptical cadre of scientists should eventually accept the dates, that Pendejo Cave – this nondescript place in the harsh Chihuahuan Desert – would be among the earliest, if not the earliest, of the known occupation sites in North America. It would be another archaeological triumph for R. S. "Scotty" MacNeish.

The First Americans

Previously, conservative archaeologists have thought that humans arrived in the Americas no more than 12,000 or maybe 14,000 years ago. More adventurous archaeologists have speculated that the first arrivals could have occurred as early as 20,000 years ago. Based on disputed data from various sites across the Americas, a few have ventured to suggest dates as old as 40,000 years ago. Most have a healthy scientific skepticism about proposed arrival dates 50,000 years or more ago.

The data from Pendejo Cave and other ancient archaeological sites have so far given us a very dim picture of the first arrivals to the arid region of the southwestern United States and northern Mexico. In fact, we have only a dim picture of how or when humans first reached the Americas. Traditionally, researchers have thought that nomadic groups of foragers must have wandered from northeastern Siberia across the Bering Strait into Alaska some tens of thousands of years ago, during one or several of the great "Ice Ages." That seems reasonable. Two-mile thick continental glaciers created a passageway by locking up massive stores of the earth’s water, lowering the sea level by several hundred feet, and exposing the Bering Strait as a land bridge.


Plausibly, over time, the foraging peoples who reached Alaska could have followed a glacier-free river basin called the Mackenzie Corridor southward through Canada into the United States. Equally plausible, they could have followed North America’s Pacific coast line by foot or by small boat southward into the United States. Unfortunately, archaeologists have found no incontrovertible evidence of the early foragers in the Mackenzie Corridor, and they have been virtually cut off from the early coastal sites by the modern higher sea level. Clouding the issue still more, some investigators have suggested within the past few years that early groups may have crossed the Pacific and even the Atlantic to reach the Americas. Possibly, over time, early immigrants to the Americas used some combination of all those routes.

Exhibit at El Paso Museum of Archaeology

The quest for the first Americans is akin to a treasure hunt with few clues and no map. The challenges to the data from Scotty MacNeish’s Pendejo Cave and other apparently ancient sites will likely continue for years.

Then and Now

When the first foraging peoples reached the southwestern United States and northern Mexico, evidently sometime during the Ice Ages, they found a climate, a landscape and animal populations very different from those of modern times. Scientists have been able to reconstruct and even map Ice Age climatic conditions and plant and animal communities of the southwestern United States and northern Mexico by studying floral and faunal remains preserved over time in places such as fossilized pack rat middens (or nests), lake bottoms, watering holes, wetland sites, bogs, former wooded regions and caves. They have found mummified camels and ground sloths in places such as caves and even volcanic vents.

During the Ice Ages, annual average temperatures in our region ranged some five to 10 degrees Fahrenheit colder than the 50 to 70 degree span we typically see today. Annual average rainfall ranged several inches higher than the two to 14 inches we usually experience today.

Subalpine forests of spruce and fir grew far down the flanks of the mountains, to elevations as low as 5000 feet. Pinyon pine, juniper and Gambel oaks grew out into the intermontane basins, from elevations of 5000 down to 1000 feet. In the southwestern United States, desert vegetation grew only at the lowest elevations, for instance, in Death Valley and along the lower Colorado River. The giant saguaro cactus, a symbol of modern Arizona, grew only far south of the border, well down in Mexico.

By contrast, in today’s hotter and drier climate, the spruce and fir forests have retreated far up into the mountains, to the elevations above 9000 feet. Ponderosa pine has extended its range northward through the Colorado Rockies, at elevations from 6000 to 9000 feet. The pinyon, juniper and oak woodlands have abandoned the basin floors, retreating to the lower flanks of the mountains. The desert has expanded from northern Mexico well up into the southwestern United States, now defining the character of northern Sonora and Chihuahua and of southern California, Arizona, southern Nevada, southern Utah, southwestern Colorado, New Mexico and western Texas.

Southwestern Ice Age animal populations included big game such as mastodons, mammoths, long-horned bison, horses, camels and giant sloths. With the end of the last Ice Age, roughly 12,000 years ago, most of the big game animals died out, unable to survive the climate change and Paleo-Indian hunting pressures. The animal community changed profoundly, although a few big game species and many smaller species have survived into modern times.

Click here to learn more about the earliest arrivals: Paleo-Indians

Jay W. Sharp



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