In addition to a drive lane, the scientists think they may have spotted camp sights and stacked stones, or cairns, that prehistoric Americans used to attract the caribou's attention.
Today Arctic hunters use "cairns to lead the caribou onto the drive lines," O'Shea explained.
The hunters "will sometimes attach ribbons to [cairns], and caribou are sufficiently curious that, when they see this, they want to come up and take a look."
Huron Mystery to Be Solved This Summer?
If the new finding is confirmed, it will be the first direct proof that Paleo-Americans living in the Great Lakes region hunted caribou on large scales like their counterparts farther north, said Michael Shott, a University of Akron anthropologist who was not involved in the study.
But Shott is not yet completely convinced the structures are human-made.
"The argument is a plausible one," he said. "But there may be natural processes that could produce both the large- and small-scale features."
Study co-author O'Shea agreed that processes such as glacial scraping could have produced the rocky lines.
The mystery, he said, could be resolved this summer, when scuba divers will examine the lake bottom.
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