The canyonlands surrounding the confluence of the Pecos River and the Rio Grande are the boundary of West Texas – and they're famed in Texas archeology. Natural shelters here preserve stunning rock art, and one of the best records of North American hunter-gatherer life.
One of these rock shelters tells a particularly dramatic story.
Bonfire Shelter is the southernmost, and perhaps the earliest, evidence of an ancient hunting technique. Here, hunters successfully steered bison into a fatal fall. Now, Bonfire Shelter is the focus of new research.
Though he never witnessed it, he described its results in the journal of his 1805 journey.
“Today we passed... the remains of a vast many mangled carcases of Buffalow which had been driven over a precipice of 120 feet,” Meriwether Lewis wrote. “In this manner, the Indians of the Missouri distroy vast herds of buffaloe at a stroke.”
Evidence of “buffalo jumps” exists across the Northern Plains, from Colorado to Canada. At a site in Alberta, evidence of the practice dates back 6,000 years.
But Bonfire Shelter, near Langtry, Texas, is unusual.
Dr. David Kilby, of Texas State University, is leading new research at Bonfire. It's part of an initiative called the Ancient Southwest Texas Project.
“It's only common on the northern Plains in late prehistory,” Kilby said of the bison jumps. “So Bonfire Shelter is anomalous in a couple of ways. It's the southernmost bison jump that we know of, and if Bone Bed 2 represents a bison jump, it's the earliest bison jump we know of – by thousands of years.”
In 1958, a Midland teenager – obsessed with prehistory – was on a family trip to Langtry. In nearby Eagle Nest Canyon, he dug bones from a talus mound inside a rock shelter. Later, a friend told him the bone was buffalo.
The teenager – Michael Collins – has become a prominent archeologist. In 1963, UT archeologists followed up on his youthful find, and excavated Bonfire. They confirmed that Collins' bone layer was bison.
Here, some 3,000 years ago, hunters steered a hundred or more buffalo to their deaths. Subsequently, the bones had burned. But archeologist David Dibble and his team found new surprises.
Below the first layer – Bone Bed 3 – they found another. This layer – Bone Bed 2 – was composed of the remains of dozens of now-extinct Ice Age bison. Among the bones, they found spearpoints – 12,000 years old.
It's the only evidence that the continent's earliest hunters – known as Paleoindians – organized bison jumps.
These ancient hunters are thought to have moved in bands of 15 to 25. It would have taken the coordination of multiple bands to execute a successful jump.
A large group would likely have approached the grazing animals slowly, edging them toward the canyon. As the herd neared the cliff, other hunters would have leapt up – to spook the animals and stampede them into their blind fall.
“And then you can imagine this really intense and chaotic situation,” Kilby said. “You have these panicked beasts – and these are big bison, these are bigger than modern bison – bellowing and panicking and spilling over the cliff top and falling a hundred feet with great impact below. Almost surely this doesn't immediately kill all of them, so you have animals below that are writhing and injured and angry and dangerous. Then you probably have a group of people below that are dispatching those animals with spears.”
Bone Bed 2 wasn't the end. Deeper still, Dibble identified Bone Bed 1. This layer – 14,000 years old or older – contains bones of mammoth and Ice Age camel and horse.
Important questions persist about Bonfire Shelter. Some researchers suggest Bone Bed 2 doesn't represent a bison jump, but rather a place where Ice Age hunters butchered animals they'd killed elsewhere.
Kilby plans to look closely at these bones. By studying bone fractures, he could determine if they were caused by a fall. He also plans new radiocarbon dating – to assess whether the bones represent one or multiple kills.
Then there's Bone Bed 1. Were the mammoth and other creatures killed by humans, or consumed here by an Ice Age bear or other predator? Kilby will sift through the sediments, to search for tiny fragments of stone tools. If he finds that evidence, it could push back the accepted date for human occupation in North America.
The Lower Pecos is a harsh and haunting landscape. It's also a window into the ancient human past.