This is a quokka, the Australian marsupial currently being billed as the "happiest animal in the world." Paging Dr. Obvious - Just look at that smile! Erm, ok, so the findings behind this claim seem to be solely rooted in the creature's anthropomorphic smile. Flimsy science, yet I am sold 100 percent. That face says it all. Just like how my aging hound is depressed when denied cheese, the quokka is the happiest animal in the world. No contest. In your face, dolphins.