Woolly mammoths were closely related to today's Asian elephants. They looked a lot like their modern cousins, except for one major difference. They were covered in a thick coat of brown hair to keep them warm in their home on the frigid Arctic plains. They even had fur-lined ears.
Their large, curved tusks may have been used for fighting. They also may have been used as a digging tool for foraging meals of shrubs, grasses, roots and other small plants from under the snow.
Though woolly mammoths went extinct around 10,000 years ago, humans know quite a bit about them because of where they lived. The permafrost of the Arctic preserved many woolly mammoth bodies almost intact. When the ground around riverbanks and streams erodes, it often reveals the corpse of a long-dead mammoth that looks much like it did when it died.
For example, in 2007 in Siberia, a pair of mummified baby mammoths were found. The bodies were so well preserved that CT scans found the mammoths died from choking on mud 40,000 years ago. The mud was like a "really thick batter that they got clogged in their trachea and they were unable to dislodge by coughing," said study co-author Daniel Fisher, the director of the University of Michigan Museum of Paleontology. "It basically prevented them from taking them another breath." [Last Terrifying Moments of Baby Mammoths Revealed]
Botanist Mikhail Ivanovich Adams recovered the first Siberian woolly mammoth fossils in 1806. Over a dozen soft-tissue specimens have been found since then.
Woolly mammoths were around 13 feet (4 meters) tall and weighed around 6 tons (5.44 metric tons), according to the International Union for Conservation of Nature(IUCN). Some of the hairs on woolly mammoths could reach up to 3 feet (1 m) long, according to National Geographic.
Though woolly mammoths are known for living in the frigid planes of the Arctic, mammoths actually arrived there from a much warmer home. Research by a team from the University of Manitoba in Winnipeg, Canada, found that the ancestors of both the mammoth and Asian elephant originated in Africa 6.7 million to 7 million years ago. They seemed to have stayed there for about 4 million years before moving up into Southern Europe.
Then, about a million years later, they spread out even further to the area that is now called Siberia and the northern plains of Canada. During this time, "a cataclysmic event occurred on Earth — the Ice Ages," said Kevin Campbell of the University of Manitoba research team. [Related: How Woolly Mammoths Survived Arctic Cold]
The woolly mammoth’s survival in much colder climates is credited by the research team to small genetic mutations that may have changed the way oxygen was delivered by its blood that could have kept them warmer.
Can the woolly mammoth be brought back?
Because many mammoth corpses are so well preserved, scientist have been able to extract DNA from the animals. One particularly good specimen was a female mammoth in her 50s, nicknamed Buttercup, that lived about 40,000 years ago.
In theory, this DNA could be used to clone woolly mammoths, bringing them back from extinction. In fact, there is a project called The Woolly Mammoth Revival that is working toward making this idea a reality.
This concept is highly contested in the scientific world. Some objections are that the mammoth’s habitat isn’t what it was when the creature roamed the Earth, so where would it live? Others contest that a habitat could be created for the creatures if they were brought back.
Another concern is how microbes have changed in the 10,000 years since woolly mammoths have roamed the Earth. Animals rely on microbes to help digest food. If the mammoth’s microbes went extinct, the animal may suffer if brought back. "In many cases, the overall phenotypes [physical appearance] of organisms and their ability to digest food is directly tied to the microorganisms in them," said Susan Perkins, a curator at the American Museum of Natural History. [Related: Woolly Mammoth Comeback? 5 Ethical Challenges]
So far, Harvard geneticist George Church and colleagues have used a gene-editing technique to insert mammoth genes into the DNA of elephant skin cells. This is far from cloning mammoths, but it is a first step to manipulating the DNA found in mammoth corpses.