Paleontologist Larry Agenbroad, who helped unearth the best-preserved pygmy mammoth skeleton ever found, is returning to Santa Rosa Island to solve a kind of prehistoric murder mystery.
Leading a six-month expedition in search of the fossilized remains of other pygmy mammoths, he hopes to explain whether a changing climate destroyed them or Indians hunted them to extinction."Was it overkill or overchill?" asked Agenbroad. "Was it people or the climate that wiped out these magnificent animals? There's a possibility that the Channel Islands may hold the key to that."
Anthropologists believe Chumash Indian predecessors first settled on the Channel Islands - a chain that includes Santa Rosa - 8,000 to 12,000 years ago. That was about the time mammoths are believed to have died out.
"The circumstantial evidence is looking stronger all the time that the first Indians that got out there saw the elephants and may have hunted them," said John Johnson, curator of anthropology at the Santa Barbara Museum of Natural History.
Inspection of the mammoth bones, however, has turned up no evidence that the animals were butchered, he said. And there are far fewer human remains on the island, since most seaside campsites have long since been submerged.
Although the first record of mammoth bone sightings on Santa Rosa dates to 1873, a full-fledged accounting of the fossils never has been made.
Mammoths are extinct elephants that roamed much of the world during the Pleistocene Epoch, which began 2.5 million years ago and ended 10,000 years ago. Most were about as large as modern elephants.
Pygmy mammoths evolved from the 12- to 14-foot-tall mainland beasts, which scientists believe swam to the islands about 20,000 years ago during the Ice Age, when the sea level was lower and Santa Cruz, San Miguel, Santa Rosa and Anacapa islands formed a single land mass.
The islands, about 25 miles from the Santa Barbara shore, are part of the Channel Islands National Park.
Over the centuries, the mammoths evolved in size to pygmy elephants 5 feet to 6 feet tall. It is a common phenomenon for descendants of large animals, restricted by an island's limited resources, to be smaller, said Agenbroad. On sabbatical from Northern Arizona University, he is the principal investigator of The Mammoth Site in Hot Springs, S.D.
Agenbroad and other mammoth specialists were ecstatic two years ago after San Diego State University geologist Tom Rockwell found the most complete dwarf mammoth skeleton ever.
The skeleton - discovered on Santa Rosa Island - was carefully exhumed, flown to The Mammoth Site in South Dakota to be restored and preserved.
The bones will be returned for exhibition at the Santa Barbara Museum of Natural History in the next two months, Agenbroad said.
Fiberglass casts of the skeleton will be on display at the Channel Islands National Park headquarters in Ventura and at The Mammoth Site.
Besides the Channel Islands, pygmy mammoth bones have been found only on Wrangel Island off the Siberian Coast.