Colossal Biosciences first idea for de-extinction. Woolly mammoths were Ice Age elephants in fur coats—built for blizzards, rocking spiral tusks, and stomping across frozen tundras like prehistoric tanks. They lived from around 400,000 to 4,000 years ago, surviving most of the Ice Age and even outlasting it on remote islands. Yep, some were still munching grass while humans were building pyramids.