Ruby is an Afghan Hound who also lives among Buster's gang of Junkyard Dogs. She is also the only other female dog member besides Angel.
Ruby seems to have a disturbing attraction to Scamp. It may be because she is one of Tramp's past girlfriends, or so she says. Whether or not this is true is unknown. She even admits to Scamp that she has "a bad case of puppy love." She eventually leaves the junkyard with the other Junkyard Dogs minus Buster, and gets adopted by a family.