Last night I watched Ashes to Ashes and there was Dog making another appearance. It's embarrassing to note but I do not remember what episode Dog first showed up in. But I'm sure it was in the early seasons so would make Dog quite old. Anybody ever do the math on that one?

26-30 years old

Dog first appeared in "Etude in Black." Columbo picked him up at the pound. As he told the vet "his time was almost up."

Heh, well, if we want to be realistic, it's not surprising that Columbo would get a second basset hound after the first one went to the Rainbow Bridge, or that Columbo would again not be able or willing to give the new dog a name other than Dog. But I choose to take the more metaphysical view: that it's the same Dog, not so much an extremely aged animal but a concept, an image that represents Columbo's alter ego and will live as long as Columbo -- or "Columbo".

Trivia: The original animal actor died of old age during the original series, and they replaced him with another dog who was younger. Peter Falk liked to tell the story of how he had to wait for the makeup artist to finish putting white clownface greasepaint on the dog, to make him look older, before Peter could sit in the chair.