Answer:
Jack: It's really a pointless question, and it has no answer. It all depends on how you define "intelligence". They are two different species, and cannot be compared. Which is smarter? A cow or a llama? A snake or a bird? You can only measure intelligence within the same species, and then that's even debatable. Is a herding dog smarter than a retriever? Is a Bengal smarter than a Persian? This question has no answer other than opinion.
Oiko: There's a book called Animal IQ that goes into this. Cats are the more intelligent but far less trainable than dogs. You would have to convince the cat that it wanted to solve the puzzle. Most cats could not care less.
Meow: Do cats eat dog poop? Enough said.
