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VOICE ONE:
This is Faith Lapidus.
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And this is Steve Ember with EXPLORATIONS in VOA Special English.Today we tell about an unusual scientific research area in theUnited States.
It is filled with the remains ofancient animals. This unusual place is in the center of Los Angeles,California. Its name is Rancho La Brea. But most people know it asthe La Brea Tar Pits.
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To understand why La Brea is an important scientific researchcenter we must travel back through time almost forty-thousand years.Picture an area that is almost desert land. The sun is hot. Apig-like creature searches for food. It uses its short, flat nose todig near a small tree. It moves small amounts of sand with its nose.It finds nothing. The pig starts to walk away, but it cannot moveits feet.
They are covered with a thick, black substance. The pig shakesone foot loose, but the others just sink deeper. The more itstruggles against the black substance, the deeper it sinks. The pigattempts to free itself again and again. It now screams in fear andfights wildly to get loose.
Less than a kilometer away, a huge cat-like creature with twolong front teeth hears the screams. It, too, is hungry. Travelingacross the ground at great speed, the cat nears the area where thepig is fighting for its life.
The cat jumps on the pig’s back. It sinks its long teeth into thepig’s neck. The pig dies quickly, and the cat begins to eat. Almostan hour passes before the cat is finished. When it attempts toleave, like the pig, it finds it cannot move. The more the big catstruggles, the deeper it sinks into the black substance.
Before morning, the cat is dead. Its body, and the bones of thepig, slowly sink into the sticky black hole.
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Scientists say the story we have told you happened again andagain over a period of many thousands of years. The black substancethat trapped the animals came out of the Earth as oil.
The oil dried, leaving behind a partly solid substance calledasphalt. In the heat of the sun, the asphalt softened. Whatevertouched it would often become trapped forever.
In seventeen-sixty-nine, a group of Spanish explorers visited thearea. They were led by Gaspar de Portola, governor of LowerCalifornia.
The group stopped to examine the sticky black substance thatcovered the Earth. They called the area “La Brea” the Spanish wordsfor “tar.”
Many years later, settlers used the tar, or asphalt, on the topsof their houses to keep water out. They found animal bones in theasphalt, but threw them away. In nineteen-oh-six, scientists beganto study the bones found in La Brea. Ten years later, the owner ofthe land, George Allan Hancock, gave it to the government of LosAngeles. His gift carried one condition. He said La Brea could onlybe used for scientific work.
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Today, the La Brea Tar Pits are known to scientists around theworld. The area is considered one of the richest areas of fossilbones in the world. It is an extremely valuable place to studyancient animals. Scientists have recovered more than one-millionfossil bones from the La Brea Tar Pits. They have identified morethan six-hundred-fifty different kinds of animals and plants. Thefossils are from creatures as small as insects to those that werebigger than a modern elephant. These creatures became trapped aslong ago as forty-thousand years. It is still happening today. Smallbirds and animals still become trapped in the La Brea Tar Pits.
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Rancho La Brea is now the home ofa modern research center and museum. Visitors can see the ancientfossil bones of creatures like the imperial mammoth and the Americanmastodon. Both look something like the modern day elephant, butbigger.
The museum has many fossil remains of the huge cats that oncelived in the area. They are called saber-toothed cats because oftheir long, fierce teeth. Scientists have found more thantwo-thousand examples of the huge cats. The museum also has manyground sloths and thousands of fossil remains of an ancient kind ofwolf. Scientists believe large groups of wolves became stuck whenthey came to feed on animals already trapped in the asphalt.
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Since nineteen-sixty-nine,scientists have been digging at one area of La Brea called PitNinety-One. They have found more than forty-thousand fossils in PitNinety-One. More than ninety-five percent of the mammal bones arefrom just seven different animals. Three were plant-eaters. Theywere the western horse, the ancient bison and a two-meter tallanimal called the Harlan’s ground sloth.
Four of the animals were meat-eating hunters. These were thesaber-tooth cat, the North American lion, the dire wolf and thecoyote. All these animals, except the dog-like coyote, havedisappeared from the Earth.
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Researchers say eighty percent of the fossils found are those ofmeat-eating animals. They say this is a surprise because there havealways been more plant- eaters in the world. The researchers sayeach plant-eater that became trapped caused many meat-eaters to cometo the place to feed. They, too, became trapped.
Researches say the number of large animals caught in the tar pitsrepresents only about three every ten years. Many more escaped.However, this represents many large animals over a period of severalthousand years.
Visitors often ask if the bones of any dinosaurs have been foundat La Brea. The answer is no. Dinosaurs disappeared aboutsixty-five- million years before animals first became trapped at LaBrea. The La Brea area and much of California was part of thePacific Ocean when dinosaurs were alive in North America.
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Rancho La Brea has also been a trap for many different kinds ofinsects. Scientists free these dead insects by washing the asphaltaway with special chemicals. The La Brea insects give scientists aclose look at the history of insects in southern California.
The La Brea Tar Pits have also provided science with interestinginformation about the plants that grew in the area. For manythousands of years, plant seeds landed in the sticky asphalt. Theseeds have been saved for research. Scientists also have foundpollen from many different kinds of plants.
The seeds and pollen, or the lack of them, can show severeweather changes over thousands of years. Scientists say theseprovide information that has helped them understand the history ofthe environment. The seeds and pollen have left a forty-thousandyear record of the environment and weather for this area ofCalifornia.
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Thousands of visitors come each year to see fossils that havebeen found at Rancho La Brea. They visit the George C. Page Museum.Mister Page was a wealthy man who became very interested in thescientific work being done at the tar pits. He gave the money tobuild the museum and research center.
At the museum, visitors can watch scientists dig bones from LaBrea’s Pit Ninety-One. The scientists dig very slowly, using smalltools similar to those used by a doctor to examine teeth. They alsouse toothbrushes and cleaning fluids to help soften and clean awaythe asphalt.
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Visitors to the museum can also see the “fish bowl,” a laboratorysurrounded by glass. Here, they can watch scientists do theirresearch. Visitors can watch the scientists clean, examine, repairand identify fossils that are still being discovered. Through thisprocess, scientists are able to answer questions and solve puzzlesabout animals and their environment from thousands of years ago.
It is exciting to stand only a few meters away and watchscientists clean the asphalt off a fossil that is thousands of yearsold. Visitors quickly learn why researchers consider Rancho La Breaa very special place.
If you have a computer that can link with the Internet, you canvisit the Rancho La Brea Page Museum. Have your computer search forthe Spanish words “La Brea.” L-A-B-R-E-A, and look for the PageMuseum link.
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This program was written by Paul Thompson. It was produced byMario Ritter. This is Steve Ember.
VOICE ONE:
And this is Faith Lapidus. Join us again next week for anotherEXPLORATIONS program in VOA Special English.