The woolly mammoth (Mammuthus primigenius) roamed the cold grasslands of Eurasia and North America from around 400,000 years ago until as recently as about 4,000 years ago — meaning mammoths were still alive when the Great Pyramid of Giza had already been standing for centuries.
Built for the cold
Woolly mammoths were closely related to modern elephants but adapted for freezing conditions: a thick double coat of fur, small ears to limit heat loss, a layer of insulating fat, and long curved tusks used for foraging through snow and, likely, for display and combat between individuals. Adults stood roughly 3 meters (10 ft) tall at the shoulder — smaller than many people expect, close to the size of a modern African elephant.
Frozen in time
Because so many mammoths died in the Siberian permafrost, an unusual number have been found remarkably well preserved — not just bones, but hair, skin, and occasionally stomach contents showing exactly what they'd last eaten. These frozen mammoths are one of the reasons scientists have been able to extract enough DNA to seriously discuss "de-extinction" projects aiming to bring back a mammoth-like animal.
The last survivors
While most mammoths died out around 10,000 years ago as the Ice Age ended, a small, isolated population survived on Wrangel Island off Siberia until roughly 4,000 years ago — thousands of years after mainland populations had already disappeared.