The sorns were among the many Martian species that fell victim to the alien invaders known as the "Mollusc". In 1898, the sorns were part of the Martian coalition, led by John Carter and Lt. Gullivar Jones, that fought back at the invaders. They were pivotal in turning the tide in the Martians' favor, as they were seen wielding orbs that are capable in creating telekinetic powers, such as dissipating the invaders' black poison gas and toppling down a Tripod with ease.
It is during the battle that Carter and Jones discovered a single captive sorn being subjective to the invaders' sadistic experiments, in which it was surgically grafted with wings.
The sorns were created by C.S. Lewis and first appeared in Out of the Silent Planet, the first book in Lewis’ Space Trilogy; the other two were Perelandra (1943) and That Hideous Strength. The Sorns are one of three species of Malacandrans. There are the Hrossa, poet-farmers; the Pfiltriggi, the artisans; and the Sorns, the scholar-philosophers.
Interestingly, it is noted in H.G. Wells' The War of the Worlds, that Wells mentioned another Martian race that closely resemble the sorns and were used as food for Wells' Martians.