Fly is a fictional character from the children's book The Sheep-Pig (retitled Babe, the Gallant Pig in the U.S.), written by Dick King-Smith and was featured in its 1995 film adaption Babe and its non-canon sequel, Babe: Pig in the City. She is a border collie who lives on the Hoggett family's farm with her mate, Rex and their pups where they and the rest of the farm animals all teach Babe the rules of the farm. After her pups are put up for sale, a heartbroken Fly is asked by Babe if he could be her son in the absence of her pups, which she accepts and later begins to teach Babe how she and Rex herd all of the sheep in the fields under Farmer Hoggett's command, aspiring Babe in wanting to herd sheep, too.