Mary-Lou is a yellow female Pekanese pup who is the same age as Tyke, the object of his affection who was squeamish to compete with her, but couldn't race because she had the measles, urging Tyke to take her place, and win the race, which he accepts. Her only appearance is "The Pink Powder Puff Racer". She was voiced by Nancy Cartwright.


  • Mary-Lou's voice actress, Nancy Cartwright, famous for portraying Bart on the Simpsons, sounds like Bright Eyes from the 1986 Show, Pound Puppies and Daffney Gillfin from the 1984 show, "Snorks".