Woolly mammoths were ancestors of the modern elephant. They evolved from the genus Mammuthus, which first appeared 5.1 million years ago in Africa. These huge, shaggy beasts went extinct more than 10,000 years ago, along with their distant cousins the mastodons. Images of woolly mammoths were painted on the cave walls of prehistoric people, and they have become part of our popular culture. There's a significant movement to try to bring the species back through cloning. Here are some facts about these fascinating creatures:

01 of 10 Tusks Were Up to 15 Feet Long Ryan Somma/Flickr/CC BY-SA 2.0 Besides their long, shaggy coats, woolly mammoths are famous for their extra-long tusks, which measured up to 15 feet on the biggest males. These huge appendages were most likely a sexually selected characteristic: males with longer, curvier, more impressive tusks had the opportunity to pair up with more females during mating season. The tusks might also have been used to ward off hungry ​saber-tooth tigers, though we have no direct fossil evidence supporting this theory.

02 of 10 Hunted by Early Humans Nandaro/Wikimedia Commons/CC BY-SA 3.0 As massive as they were—13 feet long and five to seven tons—woolly mammoths figured on the lunch menu of early Homo sapiens, who coveted them for their warm pelts (one of which could have kept an entire family comfy on bitterly cold nights) as well as their tasty, fatty meat. An argument can be made that developing the patience, planning skills, and cooperation required to bring down a woolly mammoth was a key factor in the rise of human civilization.

03 of 10 Memorialized in Cave Paintings Charles R. Knight/American Museum of Natural History From 30,000 to 12,000 years ago, woolly mammoths were one of the most popular subjects of neolithic artists, who daubed images of these shaggy beasts on the walls of numerous western European caves. These primitive paintings might have been intended as totems: Early humans might have believed that capturing woolly mammoths in ink facilitated capturing them in real life. Or they might have been objects of worship. Or, perhaps, talented cavemen might have simply been bored on cold, rainy days.

04 of 10 Not the Only Woolly Prehistoric Mammal Daniel Eskridge/Stocktrek Images/Getty Images Plunk any large, warm-blooded mammal into an arctic habitat and you can bet that it will evolve shaggy fur millions of years down the road. It's not as well-known as the woolly mammoth, but the woolly rhino, aka Coelodonta, also roamed the plains of Pleistocene Eurasia and was hunted for its food and pelt by early humans. They presumably found the one-ton beast easier to handle. This single-horned critter might have helped inspire the unicorn legend .The North American mastodon, which shared some territory with the woolly mammoth, had a much shorter fur pelt.

05 of 10 Not the Only Species WolfmanSF/Wikimedia Commons/CC BY-SA 3.0 What we call the woolly mammoth was actually a species of genus Mammuthus, Mammuthus primigenius. A dozen other mammoth species existed in North America and Eurasia during the Pleistocene epoch—including Mammuthus trogontherii, the steppe mammoth; Mammuthus imperator, the imperial mammoth; and Mammuthus columbi, the Columbian mammoth—but none of them had as wide a distribution as their woolly relative.

06 of 10 Not the Biggest Species Wikimedia Commons/Public Domain Despite its imposing size, the woolly mammoth was outclassed in bulk by other Mammuthus species. Imperial mammoth (Mammuthus imperator) males weighed over 10 tons, and some Songhua River mammoths of northern China (Mammuthus sungari) may have tipped the scales at 15 tons. Compared to these behemoths, the five- to seven-ton woolly mammoth was a runt.

07 of 10 Covered With Fat as Well as Fur Science Picture Co/Getty Images Even the thickest, shaggiest coat of fur wouldn't provide sufficient protection during a full-on Arctic gale. That's why woolly mammoths had four inches of solid fat underneath their skin, an added layer of insulation that helped to keep them toasty in the severest climatic conditions. Based on what scientists have learned from well-preserved individuals, woolly mammoth fur ranged in color from blond to dark brown, much like human hair.

08 of 10 Went Extinct 10,000 Years Ago DEA PICTURE LIBRARY/Getty Images By the end of the last Ice Age, about 10,000 years ago, pretty much all the world's mammoths had succumbed to climate change and predation by humans. The exception was a small population of woolly mammoths that lived on Wrangel Island, off the coast of Siberia, until 1700 BCE. Since they subsisted on limited resources, Wrangel Island mammoths were much smaller than their woolly relatives and are often referred to as dwarf elephants.

09 of 10 Many Were Preserved in Permafrost Andrew Butko/Wikimedia Commons/CC BY-SA 3.0 Even 10,000 years after the last Ice Age, the northern reaches of Canada, Alaska, and Siberia are very, very cold, which helps to explain the amazing number of woolly mammoths discovered mummified, nearly intact, in solid blocks of ice. Identifying, isolating, and hacking out these giant corpses is the easy part; what's harder is keeping the remains from disintegrating once they reach room temperature.