Hillary Mayellfor National Geographic News
May 11, 2001
Scientists have found the first definitive proof that early humans in North America hunted horses for their meat.
Prehistoric horses, which were much smaller than today's horses, standing about 4.5 feet (1.5 meters) high at the shoulder, became extinct about 10,000 years ago. Scientists considered it likely that hunting by humans was a factor in their extinction, but until now there was no hard proof.
The first conclusive evidence comes from spearheads tainted with the residue of horse protein. They were found along with other animal remains on the river plain of St. Mary's Reservoir in southern Alberta, Canada.
"In the past, we could really only attribute the demise of these ancient horses to climate and environmental changes," said Brian Kooyman, an archaeologist at the University of Calgary and the lead scientist at the dig.
"There has been suggestive evidence at other sites—Lubbock Lake in Texas, for instance—that early peoples were utilizing horses," he said. "But this discovery raises the very real possibility that overhunting by the Clovis people played a significant role in the extinction."
European explorers reintroduced horses to the New World several thousand years after the ancient ones died out.
Prehistoric Detective Work
The floor of the reservoir is covered with animal tracks of mammals, including wooly mammoths, camels, giant bison and helmeted musk oxen. "Clovis points," the spearheads associated with some of the first humans to reach the continent, found in the river plain have been dated to between 11,000 to 11,300 years old.
"The area where the remains were found is large—3 to 4 square kilometers [1 to 1.5 square miles]," Kooyman said. "We uncovered the remains of a prehistoric horse with several smashed vertebrae and bones that bore evidence of butchering, and then two of our students found several Clovis points around 550 yards (500 meters) away."
Laboratory analysis showed that the spearheads had the residue of horse protein on them; they apparently had been thrust into the horse.
"It was a near miss," Kooyman said of the discovery. "We weren't going to bother testing them [for horse protein residue]. We'd had similar findings before and the points all came back from the lab clean. But the two graduate students kept insisting we send them in, and we're glad they did."
"Retreating ice would cause changes in temperature, vegetation bands and probably a patchiness in vegetation and loss of habitat," said Paul McNeil, a Ph.D. candidate in paleontology at the
"Environment and climate change were definitely factors in the extinction event, but there had been numerous instances of glaciers advancing and retreating during the Pleistocene, and this is the only time we see a megafaunal extinction. The arrival of humans is the only real new factor," he said.
The lakebed where the footprints, animal skeletons and artifacts were found is usually flooded. Currently, however, the region is undergoing a drought. St. Mary's reservoir is expected to fill with water again, perhaps soon, so the scientists are working feverishly—sometimes in the midst of brutal sandstorms—to document the tracks and continue the archaeological excavations.
From a preservation standpoint, McNeil noted, the tracks are better protected under water. "One of the results of glaciations is a denuded countryside, with lots of dust and sand and silt. So when the wind blows it can be fierce enough to erode meters at a time," he said.
"The tracks represent living animals and a living ecosystem. In your mind you can see the animals cohabitating, gathering in the same place," he said. "We've found the only camel tracks we know of in North America—at one place you can see where five of them were walking next to each other."
Threatened by the filling of the lake, Kooyman said: "Right now we're just scrambling to do the really critical things."