ANN ARBOR (AP) - Evidence of prehistoric caribou hunts on the floor of Lake Huron illustrates the sophistication of ancient peoples whose survival depended on understanding the habits of their prey, scientists said Monday.
In a newly released article, underwater archaeologists described a 9,000-year-old, man-made "drive lane" where earlier civilizations had targeted caribou. It was built atop a one-time land corridor linking what is now northeastern Michigan with southern Ontario. The area, about 35 miles southeast of Alpena, is submerged beneath about 120 feet of water.
Constructed on level limestone bedrock, it consists of two parallel lines of stones leading toward a cul-de-sac formed by the natural cobble pavement. Three circular hunting blinds are built into the stone lines. Additional stone alignments may have served as blinds and obstructions for corralling caribou, researchers said.
"One reason this area was so valuable is that it provided ... predictability," said John O'Shea, a professor of anthropological archaeology at the University of Michigan and lead writer of the paper, which appears in the Proceedings of the National Academy of Sciences.
Hunters of the Late Paleoindian-Early Archaic periods "had a lot of confidence the animals would have to pass there," he said. "If you guessed wrong about where the animals are, you may very well be dead. There was a lot of pressure on getting it right."
The site and artifacts found there suggest that the hunters used "distinctly different seasonal approaches," O'Shea said. "In autumn, small groups carried out the caribou hunts, and in spring, larger groups of hunters cooperated."
Archaeologists found the site using remote underwater vehicles, sonar and other technology. They have explored the area for years and previously announced the discovery of the drive lane, along with a pole-shaped piece of wood that might have been used to hold up a tent or hang meat. But their latest article provided more detail about the drive lane, located on what is called the Alpena-Amberley Ridge.
They say the main feature, "Drop 45 Drive Lane," is the most complex hunting structure that has been found beneath the Great Lakes.
The structures in and around Drop 45, and the chipped stone debris for repairing stone tools, are evidence of human construction and use, O'Shea said. They also shed light on the social and economic organization of the ancient hunters.
"The larger size and multiple parts of the complex drive lanes would have necessitated a larger cooperating group of individuals involved in the hunt," he said. "The smaller V-shaped hunting blinds could be operated by very small family groups relying on the natural shape of the landform to channel caribou toward them."
Co-authors of the article are Ashley Lemke and Elizabeth Sonnenburg of the University of Michigan, Robert Reynolds of Wayne State University and Brian Abbot of Nautilus Marine Group International.