Scientists Toil at Mammoth Ice Age Task

His broad, powerful shoulders stood six feet tall, and he lived peacefully on an island across the Santa Barbara Channel, munching on wild grasses without fear of predators.

As he grew older, he suffered terrible arthritic spurs on his hind feet. He was 49 years old when he lay down to die.

Quickly buried by a sand dune, the skeletal remains lay undisturbed for perhaps 100,000 years, until a geologist happened to spot the gleaming, white backbone poking through sand on Santa Rosa Island.

It has been a year since the discovery and excavation of the most complete skeleton of a pygmy mammoth ever found.

A team of specialists continue the tedious task of chiseling the bones from their concrete-hard bed of sand and calcium carbonate. The team is nearly 70% done with scraping clean the partially fossilized skeleton now kept at a mammoth research center in South Dakota.

Even more painstakingly, scientists are beginning to scrape together clues about the life and death of this pygmy mammoth and others that roamed the Channel Islands during the last Ice Age.

Another breakthrough came in June when geologist Larry Agenbroad pulled a lower jawbone of a full-sized mammoth from a sea cliff on the north shore of Santa Rosa Island.

It was one more bit of ancient evidence supporting the theory that mainland mammoths--ancestors of the modern-day elephant--swam across the channel during the Pleistocene Epoch and slowly shrank in size while confined to the island.

“I’ve got two pieces of the puzzle,” said Agenbroad, America’s leading authority on mammoths. “Now the other 9,000 pieces are ready to be assembled.”

The discovery of the prehistoric bones on Santa Rosa Island continues to reverberate through certain strata of the scientific community. It has brought international recognition to the Channel Islands as one of three known sites of pygmy mammoth remains.

European and Russian paleontologists are fascinated by the find, and how it compares to the pygmy mammoth bones found on islands off Siberia and in the Mediterranean.

Yet the flurry of public interest that swirled around last summer’s excavation has dwindled. And administrators of the Channel Islands National Park have not seen an increase in visitors, as initially hoped.

The Channel Islands remain one of the least-visited national parks in California, with about 180,000 people venturing to the islands or the visitors center in Ventura annually.

And pressure has mounted this year to show strong public support because some members of Congress have threatened to unload parks with limited significance or attendance.

“I’m concerned that these bones don’t just languish in some drawer in South Dakota,” said Tim Setnicka, the park’s assistant superintendent. “We need to get something of educational value that everyone can enjoy.”

In the visitors center, the park has a small display on last year’s excavation, with photographs and a videotape. But the park’s crowded headquarters in Ventura Harbor does not have the room or the climate-controlled facilities to exhibit the skeleton. And neither the park nor its boosters have the money to set up a paleontological exhibit.

The Santa Barbara Museum of Natural History has offered to take the skeleton and keep it with its extensive collection of mammoth bones and other relics from the Channel Islands.

“The pygmy should come back to Southern California,” said Robert G. Breunig, the museum’s executive director. A corporate sponsor, he said, is close to committing the dollars to make a cast of the skeleton so it can join the museum’s exhibit on the Ice Age creatures.

Paleontologists now frown on drilling holes in prehistoric bones so they can be mounted on display, fearing that such treatment will hasten deterioration. So the skeleton would be kept in storage for scientific research, Breunig said.

“If we get the original skeleton, we would work to obtain a second cast so it could be put on display at the park’s headquarters in Ventura,” he said.

Park administrators want their visitors center to obtain a cast of the pygmy mammoth in its death pose, lying on its left side with one leg extended.

The skeleton is unique because the bones were found 95% intact. It would be best, said park archeologist Don Morris, to show off this remarkable find in its natural state.

Morris and Agenbroad believe that the mammoth was buried within days of death.

The Channel Islands are particularly hospitable to preserving relics because they have no gophers or other burrowing animals to disrupt buried bones. And there has been little development compared to the mainland.

About 2,000 years ago, a small stream began to cut through the dune that entombed the remains. Later, it washed away a tusk, a foot and part of a shoulder. But otherwise the fossil remained complete.

Morris said it was strikingly good luck that a geologist from San Diego State stumbled on the mammoth skeleton at the exact geological moment it reached the surface--and before it had been washed away.

Morris returned to the excavation site after this winter’s heavy rains. The pit created by the dig had vanished, he said. “Mother Nature had wiped the slate clean.”

During the Ice Age, the site was much farther from shore and Santa Rosa was four times the size it is now. The island was connected to the islands of Santa Cruz, Anacapa and San Miguel. That was before the glaciers melted, raising the sea level about 330 feet.

The island was also closer to the mainland, separated by just five miles of ocean. It was easier for animals to make the crossing, compared to the 30 miles that now separate Santa Rosa Island from the coast.

The ongoing research on the pygmy mammoth has stirred interest in studying the early history of the island--a time when the climate was wetter and colder, the island was thick with forests and California condors soared overhead. Graduate students are now focusing on everything from the history of fires on the island to its geological faults.

“Our studies of the mammoth will give us a glimpse of the changes that have created the island today,” Morris said.

Scientists have yet to pin down the date of the pygmy mammoth’s death. The skeleton cannot be subjected to the most accurate method--radiocarbon dating--because all of the collagen, a fibrous protein used in the process, has long since leached out of the bone.

To bracket the time of death, researchers have turned to other samples collected with the mammoth remains. Snail shells found just above the bones were dated at about 35,000 years old, and sediment beneath the find at 101,000, plus or minus 10,000 years.

Morris is awaiting the dates of other sediment samples turned over to Ohio State University to pin down the date. But the researcher there said his backlog is such that he will not complete the analysis until early next year.

“This is the unspectacular side of science,” Morris said, when research seems to grind along in geologic time.

So far, Larry Agenbroad has been able to make some determinations from the skeleton now being cleaned up at the Mammoth Site, a private research center in Hot Springs, S.D. He is the principal investigator at the ancient sinkhole where 51 mammoths have been unearthed.

The pygmy mammoth was about 40% of the size of the Columbian mammoths being excavated in South Dakota, hence its oxymoronic name. The pygmy’s shoulder is six feet high, compared to 14 feet for its mainland cousins. Using empirical formulas, Agenbroad guesses that the pygmy weighed about a ton, compared to eight tons for the Columbian mammoth.

“It looks like a lot of the dwarfing took place in the legs, although it is reduced in size overall,” he said. Dwarfism is common among island animals, possibly because of limited supply of food.

Examining the wear on the pygmy’s teeth, he calculated its age to be 49 years at the time of death.

Agenbroad was delighted to get his hands on the lower jawbone of a full-sized mammoth during last month’s excavation, assisted by Morris and Breunig of the Santa Barbara museum.

“It could be the great-great-granddaddy of these pygmy forms,” he said. “My gut feeling is that this is an older deposit.” He said he will attempt to date the fossil using surrounding sediments.