In the book, Tab is a male cat (but portrayed as a female in the movie) who taunts his prey. He also has a sort of ambition to kill Hazel. When Hazel and Pipkin were trying to steal some hutch rabbits - Clover, Boxwood, Haystack, and Laurel - from the farm, Tab tried to creep up on them. Pipkin spotted him, however, and Hazel taunted the cat into jumping at them before they made their escape.
In the animated series, Tab is characterized as a female cat known as Tabitha.
Tab appears in the miniseries where unlike the book and film, he does not speak. Unlike previous versions, it is Fiver whom Tab attacks near the end of the film instead of Hazel, only to be stopped by Lucy, who later releases Fiver back into the wild.