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A Mammoth Mummy
One long-ago summer's day, a baby woolly mammoth somehow lost his mother. He was no more than seven or eight months old, so young that he had only milk teeth and still depended on his mother for food. As he wandered around his home range, near the Arctic Circle, his body fat was quickly used up. Frantic with hunger, he tried to eat dirt and plants. Then he had an accident and fell, perhaps into an icy pit, where he soon died. In the far north, summer is short. The body froze and became encased in ice. Cave-ins buried it under six feet of earth. The ground froze and stayed frozen, except for the top few inches, which thawed each summer. In this natural deep freeze, the body of the baby mammoth was preserved for thousands of years. It became a mummy, which is the term now used for any well-preserved body, whether animal or human.
The mummy was found in June 1977. At that time Soviet gold prospectors were working near a stream in northeastern Siberia. One was running a bulldozer, digging out mud and frozen ground, when he struck a big block of muddy ice with something dark inside. Curious about what he had found, the prospector changed the flow of the stream and used its water to melt some of the ice. In a short time, the shape of a baby mammoth appeared.
The discovery was of great interest to Soviet scientists who study mammoths. Woolly mammoths, which were relatives of today's elephants, managed to survive a long period of drastic changes in the earth's climate. They lived through times when heavy snows fell, when great glaciers formed and grew so big that mile-thick sheets of ice swallowed hugeareas of land for thousands of years. They lived through times when the air warmed and the glaciers shrank, releasing floods of meltwater. Yet when the glaciers last melted and drew back, about 9,000 to 12,000 years ago, the woolly mammoths died out. How and why they did remains a mystery.
We know about mammoths from the cave drawings of Stone Age peoples and from the remains of mammoths that have been found. Over the years countless bones and tusks have been found in the far north. From time to time parts of woolly mammoths have been discovered in the frozen ground, but whole mammoths are rare. The few discovered in the 1800s rotted away or were eaten by animals before scientists could study them. The ones found in this century have not been complete. The Soviet prospectors' find, which they named Dima, was the first whole mammoth mummy that modern scientists had ever had a chance to study. In addition, only once before, in Alaska, had anyone found remains of a baby mammoth.
The mummy was flown to a laboratory in the north, where it was refrigerated to keep it from rotting. Later it was flown to Leningrad for detailed study. Samples of material from the body were shared with scientists in the United States who were trying to find out, among other things, the exact relationship of mammoths and elephants.
Early studies showed that Dima was about 4 feet tall and 4 feet long and weighed 198 pounds. His trunk measured 22 inches and had two "fingers" at the end, just like the ones that can be seen in cave paintings. The hide was now separated from the body, but in life Dima had had a shaggy, chestnut-colored coat. The soft, thick undercoat was 3 to 4 inches long and protected by a covering of wiry hairs up to 10 inches long. The trunk was furry and the outer ears were tiny. Like all woolly mammoths, Dima was well equipped to live in the far north, with a covering that trapped and held in body heat. By contrast, today's elephants live in warm or hot climates and are equipped to get rid of body heat. They have no fur, only bristles, on their leathery hides. Their huge outer ears provide extra surface area from which heat can escape.
It was clear that Dima had been hungry: His ribs stuck out through his skin. The stomach and other intestines provided more clues to what had happened. In them was only a trace of his mother's milk. Alone, he had eaten mostly dirt. With just three milk teeth, he had not been able to chew plant food but had simply swallowed some roots, stems, grass, and grass seeds. The presence of grass seeds showed that Dima had died in summer, the time of year when these seeds form. The month was most likely August, which is late summer in the arctic.
The excellent condition of the mummy was the chief clue to the kind of place in which Dima died. It must have been a cold one, cold enough to keep the body from decaying before it froze. And because the body was buried, it must have been a place where cave-ins or landslides could occur, such as a pit or the bank of a stream.
To find the age of the mummy, scientists made use of a built-in atomic clock. This is how the clock works:
Certain kinds of atoms are radioactive-they keep breaking down by giving off tiny parts of themselves. Among these atoms are those of carbon 14, which is a radioactive variety of carbon. Carbon 14 forms when the atmosphere is bombarded by cosmic rays. When it combines with oxygen, it forms carbon dioxide. This radioactive carbon dioxide mixes with the other carbon dioxide in the air.
Plants take in carbon dioxide, which they use to make their food. And so they also take in carbon 14. Every bit of a living plant contains a tiny amount of carbon 14. Animals feed on plants or on other animals that eat plants. As a result, every animal's body also contains a tiny...