Mammoth Task

Back in 2006, workers were building a new parking garage in the heart of Los Angeles, California. They had to be more careful than usual as they dug beneath the city. That’s because they didn’t want to hit a mammoth!

Scientists weren’t surprised to find ancient animals lurking beneath the city. Especially Laura Tewksbury—she works at the La Brea Tar Pits & Museum. The pits are underground pools of tar and asphalt that naturally formed beneath areas of present-day Los Angeles. Thousands of years ago, animals fell into the sticky tar. These unlucky creatures died and were preserved in the sludge.

Back in 2006, workers were building a new parking garage. It was in the heart of Los Angeles, California. They dug beneath the city. They had to be more careful than usual. That's because they didn't want to hit a mammoth!

Scientists weren't surprised to find ancient animals lurking beneath the city. Especially Laura Tewksbury. She works at the La Brea Tar Pits & Museum. The pits are underground pools of tar and asphalt. They formed naturally beneath areas of present-day Los Angeles. Thousands of years ago, animals fell into the sticky tar. These unlucky creatures died. Their bodies were preserved in the sludge.

The gooey traps formed during an ice age about 40,000 years ago, long after dinosaurs went extinct. The region teemed with animals such as giant ground sloths, camels, and mammoths. Sometimes, they fell into the pits.

Scientists have also found fossils of turtles, birds, and insects—all of which still live in California today. The tar pits provide scientists with a snapshot of ecosystems during the last ice age.

The gooey traps formed during an ice age about 40,000 years ago. This was long after dinosaurs went extinct. Then the region teemed with animals. They included giant ground sloths, camels, and mammoths. Sometimes, they fell into the pits.

Scientists have also found fossils of turtles, birds, and insects. All of these animals still live in California today. The tar pits provide scientists with a snapshot of ecosystems during the last ice age.

Tewksbury digs through big clumps of fossils from the parking lot. She uses hammers and chisels to separate the dirt from the fossils. When she gets close to a fossil, she uses a dental pick, chipping away each grain of dirt. “I get to dig up buried treasure,” says Tewksbury.

Tewksbury digs through big clumps of fossils from the parking lot. She uses hammers and chisels. This helps separate the dirt from the fossils. When she gets close to a fossil, she uses a dental pick. This helps her chip away each grain of dirt. "I get to dig up buried treasure," says Tewksbury.

Courtesy of the Natural History Museum of Los Angeles County

Laura Tewksbury

Tewksbury sends the fossils into the museum to be cleaned, identified, and catalogued in a fossil library. Researchers travel from all over the world to study this library. It helps them learn about a time when ice age giants roamed the land.

For example, scientists look at which animals thrived during warmer or cooler temperatures. This information can help predict what may happen as the climate changes. “We study the past to understand the present and predict the future,” says Tewksbury.

Tewksbury sends the fossils to the museum. There they are cleaned, identified, and catalogued in a fossil library. Researchers travel from all over the world to study this library. It helps them learn about a time when ice age giants roamed the land.

For example, scientists look at which animals thrived during warmer or cooler temperatures. This information can help predict what may happen as the climate changes. "We study the past to understand the present and predict the future," says Tewksbury.

1. Put on a smock and cover the desk with newspaper.

2. Make two model tar pits. Measure ¼ cup of molasses into each glass, using the spoon to scrape it all in. The sticky molasses represents tar.

3. Fill one bowl about an inch deep with warm water. Fill the other with the same amount of ice water. Place a tar pit in each bowl. Let them sit for 10 minutes.

4. Meanwhile, make “mammoth feet.” Put 30 pennies in each paper cup. Wrap a rubber band around each cup to form a handle over the opening. Make sure the rubber band is in the center of the cup. Label one cup “foot A” and the other “foot B.”

5. After 10 minutes, remove the glasses from the water and place them on the newspaper.

6. Using the handle, lower foot A into the glass of warm tar until the bottom just touches the tar. Don’t let go of the foot.

7. Get your stopwatch ready. Release the foot into the tar. Stop the foot from sinking after 10 seconds. Don’t remove it yet. Measure how much of the foot is still exposed. With your ruler, measure the distance from the top of the cup to the top of the molasses in centimeters to the nearest tenth.

8. Remove the foot and repeat step 7 two more times. Record your observations.

9. Using foot B, repeat steps 7 and 8 with the glass of chilled tar.