Petey is one of Bungalow's sons. He can be found in Quackenheim Museum, either on top of a case in an exhibit on the top floor or in a room down the Cat Art hall, depending on which version you're playing.
How to Rescue in Fur FightersEdit
He is on a case beside the rock exhibit. Jump onto the rocks and get on the other case and then jump to the case where Petey is.
How to Rescue in other versionsEdit
In order to rescue him, you need to push the smallest block around so that you can reach the next tallest block. From there, leap up to the top where Petey awaits. Be careful of the nearby crocodiles though!