In a recent Ask Chris column, Chris Sims was asked "Who is the best ANIMAL superhero of them all? (Inspired by [the asker] watching the pretty-mediocre "Underdog" film on cable)"
Sims goes on to meander through Comet the Wonder Horse, and Mr Talky Tawny before making his choice of Detective Chimp. At the end of the answer, however, he mentions Super Pup and includes this first video.
As the narrator mentions, the show was called The Adventures of Superpup. According to Wikipedia, only one episode - a pilot - was ever made, but it was filmed on the set of the George Reeves The Adventures of Superman show which was then a hit but headed off air. The writers took the Superman mythos, shifted it to a world of dogs instead of people, had the dog heads worn by midgets (ok, 'little people'), and used the same sets as The Adventures of Superman. Check out a little more of the one episode...
How have I never known this existed until now?