Two giant mammoths that lived and died thousands of years ago have set off a full-scale scientific expedition across a mud-soaked farm field in - of all places - Castroville, the "artichoke capital of the world."

A single gigantic molar, countless fragmented bones, some reddish hair and at least one partial tusk are among the remains of those two huge beasts that are being excavated from clay-filled land just outside the Monterey County town by a team of volunteer scientists from local colleges and scores of their students.

A specialist from UC Berkeley's Museum of Paleontology, who more than five years ago excavated a mammoth of the same species along the Guadalupe River near the San Jose airport, is heading to the site this weekend to confirm the discovery, identify the bone fragments and offer the museum's support in pursuing the extraordinary find.

Special help

And a noted molecular biologist, who was the first to unravel the genome of the woolly mammoth, a different long-extinct species, is planning to sequence the DNA of this new-found pair - perhaps a mother and its infant - in a quest of clues to their evolution from a common ancestor that may have emerged on the scene some 55 million years ago.

Unlike the woolly mammoths of the ice age, which evolved to subsist in frigid Arctic regions and rarely grew as tall as 11 feet, this pair emerging from the Castroville mud is known as the Columbia mammoths, and their huge species - as tall as 14 feet - once ranged widely in California.

Other remains of the species have been found as far south as Florida and Central America. Just when Columbia mammoths went extinct is unknown - the best guess is sometime between 14,000 and 9,000 years ago, depending on their locale.

Secret location

The excavation site's exact location and the name of the farmer who owns the land are being withheld to prevent looters, souvenir hunters and the just plain curious from invading the fenced-in area.

The story of the expedition began just before Christmas, when the Castroville farmer's crew was grading a slope on his land to ready it for planting and about 2 feet of tusk and one huge molar clanked on the blade of the grader.

A knowledgeable member of the farmer's family quickly telephoned Mark Hylkema, the Santa Cruz district archaeologist for the state park system. "We think they've found a mammoth," Hylkema recalled she told him.

He rushed to see for himself that same day, then called two friends, Timothy King, an archaeologist and anthropologist at Santa Clara University, and Daniel Cearley, who teaches archaeology and anthropology at Foothill College.

"I'm an old campaigneraround these parts," Hylkema said, "and I'm pretty used to hiking around this area in the wild when people find what are clearly artifacts from the Ohlone people or the early Spanish, or the foods they prepared. But this find was a lot different - and really exciting."

After carefully sectioning the area and deploying ground-penetrating radar from Cearley's archaeology lab, the scientists recruited students to dig and sift the sand for countless tiny fragments of bone.

The Castroville mammoth expedition has now found more of the tusk, four or five rib bones, and one or two long bones. Whether the remains are from the adult or the infant has yet to be determined.

"One of our students has found a bunch of coarse, stringy reddish-brown hair only about 30 to 40 centimeters (12 to 15 inches) below the surface, and we knew that with the ivory tusk and the hair, we might have enough to analyze our mammoth's genes for the first time," King said.

What's particularly important, he noted, is that the bones and at least the one tusk haven't been transformed into stony fossils, which could make it impossible to study their genes. The group has enlisted Stephan Schuster, a distinguished molecular biologist at Penn State whose team sequenced the woolly mammoth's DNA sequence less than four years ago.

(The woolly mammoth bears the scientific name Mammuthus primigenius, while the Castroville giants are Mammuthus columbi. Both are members of the proboscidean order, which includes today's African and Asian elephants.)

'Important discovery'

Mark Goodwin, assistant director of UC Berkeley's Museum of Paleontology who has seen detailed images of the site, called it an "important discovery."

"While the remains of Columbian mammoths are not uncommon in the Bay Area, this discovery, particularly if they represent an adult and a very young individual of the same species, would allow scientists to compare their remains and reconstruct their growth and behavior," Goodwin said.

The Berkeley museum, he said, would be glad to serve as a repository for the material to make sure it is properly conserved "now and for perpetuity," while sharing the find with the public "as discussions continue on how and where these bones would go on future exhibit."

Meanwhile, Schuster said his team is "in the initial stages of testing if any DNA has been preserved."

"This find is special, with its state of preservation," he said. "This is a very unique opportunity for everybody involved, and finding hairs with such a find is unprecedented. It largely increases our chances to take a stab at the genetic underpinnings of this animal."

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