Friday, July 08, 2005

News: Mexico footprints could be a giant archaeological step

Mexico footprints could be a giant archaeological step
By Dan Vergano, USA TODAY
Archaeologists expressed caution Wednesday about the reported discovery of 40,000-year-old human footprints in central Mexico. If the age of the footprints is verified by scientists outside the discovery team, the find would be a scientific blockbuster, rewriting the story of human migration into the New World.
This footprint, claimed to be 40,000-years old, was found near to the city of Puebla.
Bournemouth University via AP

An international team of archaeologists, led by Silvia Gonzalez of the United Kingdom's Liverpool John Moores University, this week announced the discovery of about 160 ancient human footprints in the floor of an abandoned quarry near the city of Puebla.

The results of five analytical dating techniques indicate the prints are more than 40,000 years old, the team says. A few other archaeological sites have shown that people moved into the New World more than 12,500 years ago. But the footprint dates suggest such a migration occurred far earlier.

"We think there were several migration waves into the Americas at different times by different human groups," Gonzalez says in a statement released by the university. Gonzalez says the find suggests Native Americans arrived in the region by boat rather than migrating on foot over a land bridge between Siberia and Alaska during the waning days of a glacial period that lasted from 70,000 to 10,000 years ago.

"It's big news if they can truly verify the dates," says archaeologist Daniel Rogers of the Smithsonian's National Museum of Natural History in Washington, D.C. "But the bottom line is this is still a remarkably early date, which is a source of additional caution."

At that time, exotic and huge animals dominated North America. Fearsome dire wolves, saber-tooth cats and the giant short-faced bear, which dwarfed grizzlies, preyed on mammoths, camels and sloths. The predators vanished at the end of the last Ice Age.

The researchers say the footprints are indisputably human, displaying arches, toe shapes and proportions right for people 4 feet to 6 feet tall. More than a third of the prints were made by children, they estimate.

But one archaeologist who has visited the Mexico site three times, Mike Waters of Texas A&M University in College Station, doubts the marks are truly footprints. "I think what we have here are quarry marks that have weathered into shapes that resemble footprints," he says. "On close inspection, most don't look that good."

Further, he says, some of the prints cross layers of ash from different ages, some of which he says are much older than 40,000 years. Waters is investigating a Native American artifact site at a reservoir near the quarry.

An additional reason for caution is that the footprint team's results have not been published in a peer-reviewed study, says archaeologist David Hurst Thomas of the American Museum of Natural History in New York. "That doesn't mean they are wrong, but science by press release won't convince anyone."

People using boats had migrated to Australia about 50,000 years ago, so similar travel to North America isn't impossible to imagine, he says.

The research team reports it has received a $372,000 grant to continue the search for more footprints buried deeper in the quarry rock. "I think that is the right approach," Waters says. "If they can find prints embedded deeper in the rock, in one layer, that would be more convincing."

Paul Kekai Manansala