"When National Geographic deems an animal 'the happiest on earth', you take note. And sure enough, the smiling, teddy-bear sized marsupials known as quokkas get that name for good reason."
I have seen rock wallabies in the wild in the Northern Territory, hanging about on a huge, reddish-coloured rocky face of a river gorge. They just hopped from rock to rock and then stopped and looked at us from across the gorge.