阅读：AnimalsLivedDiedthousandsofyearsago
bob doughty: to understand why la brea is an important scientific research center we must travel back through time almost forty thousand years. picture an area that is almost desert land. the sun is hot. a pig-like creature searches for food. it uses its short, flat nose to dig near a small tree. it finds nothing. the pig starts to walk away, but it cannot move its feet.
they are covered with a thick, black substance. the more it struggles against the black substance, the deeper it sinks. it now screams in fear and fights wildly to get loose.
less than a kilometer away, a huge cat-like creature with two long front teeth hears the screams. it, too, is hungry. traveling across the ground at great speed, the cat nears the area where the pig is fighting for its life.
the cat jumps on the pig and kills it. the pig dies quickly, and the cat begins to eat. when it attempts to leave, the cat finds it cannot move. the more the big cat struggles, the deeper it sinks into the black substance.
before morning, the cat is dead. its body, and the bones of the pig, slowly sink into the sticky black hole.
faith lapidus: scientists say the story we have told you happened again and again over a period of many thousands of years. the black substance that trapped the animals came out of the earth as oil.
the oil dried, leaving behind a partly solid substance called asphalt. in the heat of the sun, the asphalt softened. whatever touched it would often become trapped forever.
in seventeen sixty-nine, a group of spanish explorers visited the area. they were led by gaspar de portola, governor of lower california.
the group stopped to examine the sticky black substance that covered the earth. they called the area “la brea,” the spanish words for “the tar.”
many years later, settlers used the tar, or asphalt, on the tops of their houses to keep water out. they found animal bones in the asphalt, but threw them away. in nineteen-oh-six, scientists began to study the bones found in la brea. ten years later, the owner of the land, george allan hancock, gave it to the government of los angeles. his gift carried one condition. he said la brea could only be used for scientific work.
bob doughty: today, the la brea tar pits are known to scientists around the world. the area is considered one of the richest areas of fossil bones in the world. it is an extremely valuable place to study ancient animals. scientists have recovered more than one million fossil bones from the la brea tar pits. they have identified more than six hundred different kinds of animals and plants.
the fossils are from creatures as small as insects to those that were bigger than a modern elephant. these creatures became trapped as long ago as forty thousand years. it is still happening today. small birds and animals still become trapped in the la brea tar pits.
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the skeleton of a saber-tooth cat at the page museumthe museum also has many fossil remains of the huge cats that once lived in the area. they are called saber-toothed cats because of their long, fierce teeth. scientists have found more than two thousand examples of the huge cats.
the museum also has thousands of fossil remains of an ancient kind of wolf. scientists believe large groups of wolves became stuck when they came to feed on animals already trapped in the asphalt.
bob doughty: in nineteen sixty-nine, scientists began digging at one area of la brea called pit ninety-one. they have found more than forty thousand fossils in pit ninety-one. more than ninety-five percent of the mammal bones are from just seven different animals. three were plant-eaters. they were the western horse, the ancient bison and a two-meter tall animal called the harlan’s ground sloth.
four of the animals were meat-eating hunters. these were the saber-tooth cat, the north american lion, the dire wolf and the coyote. all these animals, except the dog-like coyote, have disappeared from the earth.
faith lapidus: researchers say ninety percent of the fossils found are those of meat-eating animals. they say this is a surprise because there have always been more plant-eaters in the world. the researchers say each plant-eater that became trapped caused many meat-eaters to come to the place to feed. they, too, became trapped.
