The quokka (Setonix brachyurus) is a small marsupial native to Australia, particularly known for its friendly demeanor and perpetual smile, which has earned it the nickname "the world's happiest animal." Quokkas have a round, compact body covered in coarse brown fur, short rounded ears, and a small, black nose. They belong to the same family as kangaroos and wallabies, and like their relatives, they are herbivorous and primarily nocturnal.

Quokkas are highly social animals and often live in groups. They are most commonly found on Rottnest Island, off the coast of Western Australia, where they have become a major tourist attraction. Visitors to the island love taking selfies with these approachable and curious creatures. Despite their friendly appearance, quokkas are wild animals and should be treated with respect. They are excellent climbers and can be found in dense vegetation during the day, resting to avoid the heat, and becoming active at night.

The reproductive cycle of quokkas is fascinating. Females give birth to a single joey, which spends about six months in the mother's pouch before gradually becoming more independent. Quokkas have a unique defense mechanism: if threatened, a mother may drop her joey to escape a predator, allowing her to survive and reproduce again. Quokkas have a diet consisting mainly of grasses, leaves, and other vegetation, and they have adapted to survive on relatively low water intake by deriving moisture from their food.

The population of quokkas on the mainland of Australia has declined significantly due to habitat loss, predation by introduced species like foxes and cats, and changes in their environment. However, on islands like Rottnest, where predators are absent, their populations remain stable. Conservation efforts are focused on habitat protection and management of predator species to ensure the survival of this unique and endearing marsupial.