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Encyclopedia Britannica on the Pits



Rebecca and Neda find out that Los Angeles is "the Pits."


Between the metal and glass buildings of downtown Los Angeles and the star-studded streets of Hollywood, lies a bubbling mess of sticky, black goo on Museum Row. Trendy SoCal businessmen and women hurry past these mucky pits on their lunch breaks, oblivious to the thousands of years of history located just steps away. Welcome to the Rancho La Brea Tar Pits!

A recreation of a trapped mammoth appears in a bubbling pit along busy Wilshire Boulevard
Saber-toothed cats, elephant-like mammoths, dire wolves, and huge ground sloths used to inhabit this area 30,000 years ago. All of them lost their lives passing through these pits, just as unaware as the busy humans are today. Neda and I decided to stop by the sludge ourselves, explore the rich history of the area, and get to the bottom of this mess!

Senior Excavator Gary Takeuchi climbs out of Pit 91
Well, get to the bottom we did! After pulling plastic booties over our sneakers to keep 'em clean, we climbed down a fifteen foot ladder into the bottom of pit number 91. Down below, we experienced first-hand a paleontologist's dream dig. Led by senior excavator Gary Takeuchi, we found ourselves in the middle of an asphalt hole, staring straight at the ancient pelvic bone of a giant ground sloth that volunteers and paleontologists were working carefully to remove intact! What exactly was going on here?

According to leading scientists, Rancho La Brea is one of the world's richest fossil deposits. The gooey asphalt (commonly referred to as "tar") has trapped and preserved three million fossils - more than 650 species of animals and plants. Each summer, Gary's team climbs down into Pit 91 to uncover more than 1,000 vertebrate fossils and 50 five-gallon buckets of sediment filled with microfossils. Christopher Shaw, collection manager of the Page Museum, brags that "there's nowhere else in the world where the public can watch paleontologists discover 15 to 25 fossils each day that are between 27,000 and 30,000 years old." Neda and I were lucky enough not only to watch the paleontologists at work from the public observation deck, but to be right inside the pit with them!

Rebecca's boots appear next to volunteer excavator Karolyn Knoll
Neda and I stepped carefully around the five excavators who were perched on wooden planks inside the pit as our leader Gary told us about his job. He said that removing bones from the sludge was actually pretty easy. The asphalt had preserved the actual bones perfectly, and there was no need to make casts of brittle remains, as paleontologists must do at other digging sites. Also, "There is so much to find in the pit," he said, "It's not a question of whether we'll find a bone each day, but what kind will it be?!" Once Gary's team takes the bones out, they carry them across the park to the Page Museum where scientists and volunteers carefully clean, identify, label and catalogue the fossils. Neda and I got to watch this careful process later that day, through the windows inside the Museum.

The skull of a mammoth Mammoth!
Inside the museum we checked out complete skeletons of a saber-toothed cat and a huge 15,000-pound, 12- foot tall mammoth. (Is it any wonder how the mammoth got its name?) We found exhibits that showed how the sticky asphalt held on to animals and plants, and we tried to pull up metal "limbs" (that represented animal legs) from a vat of gooey stuff. Using all of our strength, it was tough even for BOTH of us to pull up one! The poor, trapped animals didn't have a chance. We saw how the asphalt became warm in the summer, seeping up to the ground surface where it would trap unaware animals. Then we learned that carnivores like the lion would decide to stop and feast on the struggling animals, and would become trapped in the asphalt themselves!

We discovered that the fossils from Pit 91 provide important information to scientists about the landscape and environment of Los Angeles during the Ice Age. Dr. John Harris, chief paleontologist for the Page Museum says that, "Much of the wildlife we glimpse today was alive during this time, along with large, exotic creatures such as mammoths and giant ground sloths that were hunted by saber-toothed cats and American lions. Though early man was alive [elsewhere] during this time, he didn't appear in North America until 8,000 years later." Harris adds that the fossil record reveals that there was a drastic worldwide change in the temperature 11,000 years ago. The climate warmed 5-7 degrees in the very short time span of 50 t0 100 years. The environmental change from the hotter temperatures may have led to the extinction of many of the larger mammals found at Rancho La Brea.

After emerging from the excavation pit, Neda and I stopped to talk with some of the students who had been watching us from the observation deck up above. These 5th graders were studying fossils in their summer school class and had made some imitation fossils of their own. Education Interpreter Eric Soto was on hand to answer their questions and show them replicas of fossils found in the pits that the students could actually touch! Some were disappointed that there were no dinosaur bones (the tar pits themselves weren't around when dinosaurs walked the earth 65 MILLION years ago), but most had to admit that this was one amazing field trip. "This is so cool!" they told us. Yup, even in the 100 degree heat of the summer afternoon, Neda and I agreed that this gooey mess was pretty neat.


Please email me at: rebecca@ustrek.org


Links to Other Dispatches

Nick - Checking out the "battle royale" over the first humans
Stephanie - Brains vs. brawn: mammoths on the run
Teddy - The debates from the dinosaur age rage on
Team - Where did all these people come from, anyway?
Team - Think Dinosaurs are Scary? Try Greenhouse Gasses!