Quokka

The quokka is a small macropod marsupial native to a limited area of southwestern Australia, most famously found in large numbers on Rottnest Island near Perth, with smaller mainland populations in forest and scrubland. About the size of a domestic cat, it has round, forward-curving ears, coarse brown-grey fur and a habit of holding its mouth in a way that resembles a smile, which has made it a viral sensation in tourist photographs. Quokkas are herbivorous, browsing on leaves, stems, bark and grasses, and like other macropods they hop on strong hind legs and can go for extended periods without drinking free water, obtaining much of what they need from vegetation. They are mainly nocturnal, sheltering during the day in dense vegetation to avoid heat and predators. Mainland quokka populations have declined sharply due to habitat clearance and predation by introduced foxes and cats, and the species is classified as vulnerable, even though the predator-free Rottnest Island population remains large and stable.