"Everything's covered in tar," said 6-year-old Nathan Hoshizaki, as he and his two brothers peered into Pit 91 at the La Brea tar pits.
Everything, indeed. The walls, the floor, the ladder, the people--anything and anyone that ventured into the dark, gaping hole in the middle of Hancock Park is at least smudged, if not unceremoniously coated, in black, sticky asphalt.
The preoccupation with cleanliness, however, is quickly wiped away as Nathan and his family, from behind the glass at the Visitor Observation Station, realize the gooey prehistoric grave is jam-packed with fossils popping out all over the place.
"My wife and I were going to take the boys to the Page Museum [of La Brea Discoveries]," said Nathan's father, David Hoshizaki. "And this is neat, to first see how it all got there."
Wednesdays through Sundays, now through Sept. 7, the public can watch for free as workers brush and dig with tiny tools, carefully scraping away the asphalt (commonly referred to as tar) from the big bones and tiny teeth in a 3-foot square of the 14-foot-deep pit.
Paleontologists and volunteers can't work fast enough to extract the Ice Age fossils. Thousands of specimens have already been excavated from just this one location of the former Rancho La Brea ("Tar Ranch"), a 23-acre property donated to the county in 1924. It's estimated that about 4 million fossils, dating back 10,000 to 40,000 years, have already been recovered. And because of the saturation of the asphalt, the fossils are "preserved as bone here rather than being minerally replaced or petrified."
"Working on this stuff, we have the ability at any time to pick up something no human being has ever touched before," said Jerry Smith, one of two paid excavators.
Since excavation resumed during the 1984 Olympics, paleontologists and volunteers return to Pit 91 for two months each summer--the amount of time that funding allows. Sporting hard hats and sitting on upturned buckets, the workers sift through piece after piece of the puzzle to the past.
On opening day of this summer's excavation, one reporter wandered over to a circular area framed by wooden planks, its shiny black surface mostly obscured by a thin layer of dust and leaves. An unseen sticky patch no thicker than fly paper grasped the reporter's foot, at the edge of what turned out to be Pit 10.
"This shows how animals got trapped," said John Harris, director of Page Museum. "It's all rather innocent looking."
Over a period of 40,000 years, Harris explained, the asphalt would heat up in the hot summers and get sticky, and leaves and debris would camouflage the hazardous tar pool. An animal would walk into the patch--and a feeding frenzy would follow.
"It only takes two to three inches to totally immobilize a cow or bison," Harris said. "In would come a saber-toothed cat to feed on the bison, and he'd get stuck. The vultures would come, and they'd get stuck. Then come the insects, and that's how it built up. Pretty soon, you have a fair sprinkling of the local population."
And that's why, Harris added, there are piles of bones--and very few complete skeletons--found in the pits. But the pits are, of course, a gold mine for information about early life in L.A.
In the original excavation of Pit 91, from 1913-15, researchers were only interested in big bones. Today, Harris said, everything that comes up is examined, down to the minutest particles. That's one reason why the process is so painstakingly slow.
"Our aim is not to go for the trophy specimens," Harris said, "but to find out what we can about the environment."
A smaller find may not be as visually impressive as a saber-toothed cat or a giant ground sloth, but it does offer a lot more information to researchers. "A saber-tooth would wander hundreds of miles," Harris said. "A land snail would not. The smaller critters, the wood, seeds and insects, tell us a lot more about the climate in the L.A. Basin. It was once a lot cooler and wetter than today."
During the next several weeks, buckets of asphalt and fossils will be hauled into the paleontology lab inside the Page Museum. The lab, referred to as "the fish bowl," is a glassed-in room where museum visitors can watch the researchers and volunteers at work.
Nic LeCorvec, a 16-year-old Loyola High School student who lives nearby, used to spend many hours gazing at the museum's fossils of mastodons, saber-toothed cats and mammoths, from the other side of the glass. Now he's a museum volunteer. Dressed in a white lab coat, he picks away at the matrix (asphalt and other debris attached to a fossil) that is stuck to a horse's leg bone.
"It's pretty cool," LeCorvec said, as he used solvents, a toothbrush and dental pick to separate debris from the bone. "I always wanted to see what it was like behind the counter."