The Original Mammoths (PROSE: White Canvas) were the original generation of Mammoths, native to the pre-universe. They were ruled by Cernunnos and were the rulers of the painted warriors and humanity, who they created using breeding-engines. They had great psychic powers. (PROSE: Cobweb and Ivory)
In the pre-universe, there existed cities carved into gigantic ivory tusks where scholars and philosophers rode on the backs of steam-powered mammoth skeletons. (PROSE: Christmas on a Rational Planet) These cities were inhabited by the mammoths. (PROSE: Cobweb and Ivory)
After the Time Lords eradicated irrationality from reality and created history, (PROSE: Christmas on a Rational Planet) Cernunnos ordered the humans to hunt mammoths to extinction. A trace of loyalty to mammoths remained in humanity's collective memory for billions of years, and Cernunnos was eventually resurrected the posthuman era by a group led Linemica. These posthumans built a planet for the mammoths, Terra Primagenia.
Cernunnos found the remains of a pre-universe mammoth city with the unwitting help of Avus, and used it as a base to begin planning to undo the anchoring of the thread in a War against the Great Houses. (PROSE: Cobweb and Ivory)
In the post-War universe, Cernunnos was stranded on 1774 Earth in a weakened state. (PROSE: The Adventuress of Henrietta Street, Cobweb and Ivory, Grass, COMIC: Political Animals) As late as 1804, Thomas Jefferson believed that woolly mammoths still roamed the North American midwest and even sent an expedition to find one. (PROSE: Grass, The Adventuress of Henrietta Street)