The solution to the mystery of Joe Malik's dogs - several of his neighbours report hearing them, but Joe's apartment contains no evidence he ever owned any (e.g. no food bowls, leashes, etc) - was revealed by Wilson in one of his later books. All the information needed to solve the mystery is provided in Illuminatus!, but if you're tired of banging your head against that particular wall, it is as follows: Malik does not own any dogs. He does, however, own a recording of wolf howls, which he likes to play real loud when he's stoned.
