The earliest dogs in North America are believed to have come with the early settlers across the Bering land bridge from Asia to the Americas 10,000 years ago or earlier, said Wayne, who has not seen Belknap's research.

It doesn't surprise Belknap that dogs were a source of food for humans.

A lot of people in Central America regularly ate dogs, he said. Across the Great Plains, some Indian tribes ate dogs when food was scarce or for celebrations, he said.

"It was definitely an accepted practice among many populations," he said.

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