N American Civilization as Old as Asia, Mideast

They offer dramatic evidence that the earliest human colonists of the hemisphere swept down from the land bridge between Asia and Alaska much earlier than scientists previously believed, and that some of the immigrants may have been Caucasoid, or European, in origin.

New dating of squash seeds discovered in a cave in Central Mexico 30 years ago suggests that hunter-gatherers there were practicing agriculture as much as 10,000 years ago, 4,000 years earlier than scientists had believed and roughly the same time that agriculture began in the Near East and China.

"This is a very healthy and exciting time for archaeology in the Americas," says Bruce Smith, head of the archeobiology program at the National Museum of Natural History here and author of the Science article.

The article comes just a week after the publication of the second and final volume of research on the Monte Verde archaeological site. The site, on the banks of Chinchihuapi Creek in southern Chile, was apparently inhabited by people 12,500 years ago, according to more than 30 radiocarbon tests of charcoal, wood, and ivory.

Originally excavated from 1977 to 1985, that date is 1,000 years older than the earliest known human artifacts in the Americas, discovered at Clovis, New Mexico, in 1932. Known for their bifacial spear points, Clovis people were mammoth hunters who are believed to have moved across the Bering Land Bridge and spread southwards about 12,500 years ago.

Scientists had assumed that Clovis people were the earliest settlers of the Americas.

But remains found at Monte Verde upset that assumption, particularly because of the enormous distance which would have had to have been covered between the Bering land bridge and southern Chile. The remains include wooden lances and mortars, planks and stakes, hundreds of stone artifacts, and more than 60 species of medicinal and other plants gathered from sources up to 400 kilometers away.

The "implications are profound," says David Meltzer, an anthropologist at Southern Methodist University in Texas. "(Monte Verde) indicates initial arrival in the Americas must have occurred much earlier than 12,500 years ago."

Whether such early immigrants included Caucasian, as well as Mongoloid peoples from Asia, is uncertain. Much of the most recent speculation rests on the remains of two men, one whose mummified upper body was discovered in a cave in Nevada in 1940, and another whose nearly complete skeleton was discovered just last summer in the northwestern United States.

According to recent radiocarbon dating, both men died about 9,400 years ago, and both betray Caucasoid features in their face and skull. Combined with the more incomplete remains of five other people discovered in North America over recent years, the finds are contributing to a growing belief that modern-day indigenous groups in the United States may have derived from more than one broad racial category.

The existence of Caucasoid-type people in North America would also help explain what has long been an anthropological anomaly in East Asia: the Ainu people of Japan.

The Ainu, a dwindling indigenous group whose hairy bodies, light skin, and wavy hair contrast sharply with the Mongoloid people who invaded modern-day Japan from China, are believed to have lived on the islands off northeast Asia for millennia.

Douglas Owsley, a forensic anthropologist at the National Museum here, has examined the Nevada mummy and says it closely resembles the Ainu.

Like Monte Verde, the latest discovery about early American agriculture is also based on improved dating techniques applied to older discoveries, in this case, squash fragments found in caves in Oaxaca in the 1960s and kept at the National Anthropology Institute in Mexico City.

These fragments included larger seeds and stems, thicker rinds, and more colorful outer skin than are characteristic of wild species, suggesting that humans had domesticated them over time.

But Smith discovered through new testing techniques last year that cultivation of squash dates to between 8,000 and 10,000 years ago. This is 4,000 years before the domestication of corn and beans in the Americas, and is roughly coincident with the cultivation of grains such as barley and rice in the Fertile Crescent and China.

"This is pushing agriculture way back, right back to the same time frame as the Near East and China," Smith told IPS.

But in contrast to those two regions, the transition to agriculture-based village life, was apparently much slower in the Americas. "Evidence of real, village-based agriculture doesn't appear in the Americas until 4,000 years ago," says Smith. "So these people remained hunter-gatherers with the single exception of squash."

"In the Near East and China, people were living in villages completely committed to agriculture within 2,000 years of its invention," says Jared Diamond of the University of California at Los Angeles. "It took much longer to develop a complete food package in the Americas."

Agricultural practices also spread more slowly in the Americas than in Eurasia, says Smith. It was not until 5,500 years ago that squash cultivation spread to northeastern Mexico. It was introduced into what is now the southwestern United States just 4,000 years ago. Grain cultivation spread more quickly in Eurasia.

The difference, says Smith, may relate to the relative continuity of climates in Eurasia, which has an east-west orientation, in contrast to sharp changes in climate encountered along the north-south axis of the Americas.