The Mrem were the first mammal species to achieve sentience on a reptile-dominated planet. Descended from cats, the Mrem were pack hunters in the polar regions of the world, where they were isolated from the Liskash, the world's most intelligent reptile species. As the Ice Age was drawing to a close, the Mrem of necessity migrated southward, with a shortage of living-space resulting in battles between Mrem clans. More urgently, the powerful Liskash took notice of the Mrem, seeing the advantage of keeping the mammals as slaves or livestock.
The Mrem were created by editor Bill Fawcett for the multi-author Guardians of the Three series in 1989. They reappeared in the same editor's Shattered Light series in 1999. The Clan of the Claw series, of which Harry Turtledove's "The Mrem Go West" (2011) is the first installment, appears to be a continuity reboot without reference to prior storylines.