Tortoiseshell describes a coat, not a breed: black-based and orange-based colors blended in patches or a fine mottled mix, usually with little or no white. Because the orange gene sits on the X chromosome, nearly all torties are female. Most are domestic shorthairs or longhairs, though the pattern also appears in Persians, Maine Coons, British Shorthairs and many other breeds.
The famous "tortitude" is mostly folklore, backed by owner impressions and limited evidence. A cat's age, history and socialization say far more about personality than color does. Typical torties weigh 6 to 14 pounds and often live 12 to 18 years, so adopting one is a long commitment to daily play, scratching outlets and regular vet care.