Watch the movie, and you'll see that wonder mutt lost his favorite toy, the head of a stuffed doll in the ocean. Later, Mark Harmon is shown cutting the head off of a similar doll. He then turns to the now depressed dog and says "Wonder mutt, look I found Bob!" the camera shows a close up of the doll's head and, in the background, you can clearly see Mark's mouth NOT moving when he is speaking.