Scientists recently found a treasure trove of bones from woolly mammoths like this one.
Vocabulary fossils: the remains of plants or animals that have been preserved in rock ice age: a period of time, long ago, when large parts of Earth were covered with ice excavation: the digging up of an area to find buried remains minerals: substances found in the earth that do not come from a plant or an animal theories: ideas that try to explain how or why something happens; they may be based on facts, but are not yet proven 8
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Ice Age Death Trap
PAGE 8: Gary Hanna, PAGE 9: Denver Museum of Nature and Science
Why did thousands of animals die at one mountain lake? Scientists are trying to solve the mystery. It was October 2010. Construction worker Jesse Stone was digging out a lake in Snowmass Village, Colorado. Something got stuck in his bulldozer. Stone stopped the machine. He got out to take a look. What he saw scared him. It was a huge jawbone. And there were more big, brown bones on the ground in front of the bulldozer. Stone thought the bones might be fossils. Scientists came to look. Indeed, the bones were from a giant ice age animal: a woolly mammoth! Scientists did some more digging at the lake. Over the next 11 months, they found more than 27,000 fossils. The fossils came from nearly 60 species of plants and animals. They ranged from 50,000 to 130,000 years old.
The excavation was called the Snowmastodon Project. It offered a look into ice age life. And it raised a question: Why did so many creatures die at this lake?
A Rare Find Experts found fossils from bison, camels, giant sloths, snakes, salamanders, and more. They found bones from
mastodons too. These huge, elephant-like beasts died out about 10,000 years ago. Fossils form when minerals replace all or part of a dead animal or plant. The lake water at Snowmass was full of minerals. It seeped through dirt and mud to reach the dead animals and plants. When the water dried up, it left minerals behind. This fossil—a claw from a giant ground sloth—was found at the Snowmass Village dig site.
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It’s rare to find so many different ice age animals in one place. Experts think that all of the animals came to the lake to drink, bathe, and play. And, somehow, many died there.
Ice Age Wipeouts
Dig workers uncovered fossilized trees on the lake’s ancient shoreline.
earthquakes caused landslides. Then soil mixed with water to make quicksand. That would have sucked up nearby animals, even huge mastodons. Then the quicksand hardened. The creatures were buried alive. Richard Stucky, from the Denver Museum of Nature
At Snowmass, scientists found the remains of more than 30 mastodons, including these teeth.
Scholastic Action | March 24, 2014
and Science, disagrees. He says the creatures likely died from natural causes. Then, bit by bit, soil washed into the lake and buried the remains.
Looking Ahead So far, no one can prove either theory. Experts are studying the fossils to learn more. “We may never know the answer,” says Johnson. “There might not be enough evidence to really tell the story.” The puzzle may never be solved. But the project gave scientists new ideas about where to look for fossils. Says Stucky, “The Snowmastodon Project will change the way science is done in the future.” —Jennifer Marino Walters
Denver Museum of Nature and Science (all photos)
The Snowmass fossils have taught scientists more about animals, plants, and weather during the ice age. But the mystery remains. Why did all those creatures die at this lake? Was something or someone killing them? No one knows for sure. There are two main theories. Kirk Johnson, from the National Museum of Natural History in Washington, D.C., thinks that earthquakes and landslides were the cause. It could be that