An extra-toes cat isn't a breed. It's any cat born with polydactyly, a harmless genetic variation that adds toes to one or more paws. The trait is dominant, so one affected parent can pass it on. It's most common in New England and Atlantic Canada, where sailors prized big-pawed ship cats as mousers. The "Hemingway cat" nickname comes from Ernest Hemingway's six-toed cat, Snow White.
Most polydactyls in shelters are domestic shorthairs or longhairs, so size, coat and personality vary widely from cat to cat. Expect a medium-sized cat, usually 6 to 15 pounds, with moderate shedding that depends on coat length. A longhaired cat needs regular brushing, while a shorthair gets by on less. Whatever the coat, the extra claws should be checked and trimmed every few weeks.