A trail of 13 fossilized footprints running through a valley in a desert in northern Mexico could be among the oldest in the Americas, Mexican archeologists said. The footprints were made by hunter gatherers who are believed to have lived thousands of years ago in the Coahuila valley of Cuatro Cienegas, 190 miles (306 kms) south of Eagle Pass, Texas, said archaeologist Yuri de la Rosa Gutierrez of Mexico's National Institute of Anthropology and History. "We believe (the footprints) are between 10,000 and 15,000 years old," De la Rosa said. "We have evidence of the presence of hunter gatherers in the Coahuila desert more than 10,000 years ago."
     De la Rosa said there have only been initial tests to find the age of the prints and more tests will be carried out both in Mexico and at a laboratory in Bristol in Great Britain. The oldest discovered footprints in the Western hemisphere are in Monte Verde, Chile, and are believed to be 13,000 years old. There 6,000-year old footprints in the U.S. state of California, in Brazil and in Nicaragua. The age of the Mexican footprints is dwarfed by those found in Africa. The oldest known hominid foot marks are in Laetoli, in Tanzania, and are believed to have been made 3.5 million years ago.
     The Cuatro Cienegas footprints were discovered in May embedded in a white rock called travertine. Each footprint is 10 inches (27 cm) long and under an inch (2 cm) deep. They spread over a distance of 30 feet (10 meters). It is likely they were imprinted in mud and preserved by some rapid change in the environment, said Arturo Gonzalez, director of the Desert Museum, in the Coahuila state capital of Saltillo. "There must have been a natural phenomenon to rapidly cover them so they were not rubbed out and were perfectly preserved," Gonzalez said.
     In 2003, researchers found what they believed were 40,000-year-old footprints in a quarry in central Mexico. Largely discredited, that find could have greatly changed the understanding of human history in the Americas. Archaeologists with Mexico's National Institute of Anthropology and History are investigating the area around Cuatro Cienegas to further determine the footprints' age.

Sources: Associated Press, icWales, Reuters, Yahoo! News (26 October 2006)