for National Geographic News
Under North America's second largest lake, robot-assisted archaeologists may have discovered prehistoric American camps and long "drive lanes" built to guide caribou to their deaths, a new study says (caribou pictures and facts).
On what was once dry land, the structures likely date back 10,000 to 7,500 years. At the time, a vast land bridge divided what is now Lake Huron, researchers say (Lake Huron map).
Now mussel- and algae-encrusted, the features were uncovered by sonar and underwater robots at depths ranging from 60 to 140 feet (18 to 43 meters).
Walk This Way, Caribou
The line resembles lanes still used by Arctic caribou hunters, according to the study.
"An interesting behavioral trait of caribou is that they follow linear features," said University of Michigan archaeologist John O'Shea, who co-authored the new study, which will be published tomorrow in the journal Proceedings of the National Academy of Sciences.
"The hunters recognized this, and the drive lanes were a way of casually suggesting, Why don't you walk this way?"
The drive lane may have been built by early North American settlers called Paleo-Americans—ancestors of later Native American tribes.
The stone line is relatively straight but curves inward at one point.
O'Shea thinks the curve may have been a hunting blind, where hunters waited to ambush animals as they approached.
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