Tortoiseshell describes a coat, not a breed. A tortie's fur mixes black-based and orange-based colors in patches or a fine mottled blend, usually with little or no white; a cat with large white areas is called a calico. Dilute torties show soft gray and cream, and torbies add tabby stripes. Because the orange gene sits on the X chromosome, nearly all torties are female.
Most tortoiseshells you'll meet are domestic shorthairs, though the pattern shows up in many breeds. The reputation for "tortitude" is closer to folklore than proven fact. A cat's history, age and socialization say far more about personality than color does, so expect a range from shy to bold. Shedding is moderate, which in Santa Barbara's mild, dry climate usually means a weekly brushing and a lint roller near the sofa.