Quokka (Setonix brachyurus)

The quokka (Setonix brachyurus) has earned its reputation as the world's happiest-looking animal, with its permanent smile making it irresistibly photogenic. These small marsupials native to Western Australia's Rottnest Island display remarkably friendly behavior, often approaching humans with curious confidence. Their round faces, beady eyes, and cheerful expressions have made them social media darlings. Though nicknamed "the world's most cheerful animal," their smile is actually a physiological adaptation for thermoregulation. As herbivorous nocturnal creatures, quokkas play an important ecological role while captivating everyone who encounters their seemingly joyful disposition. Their fearless cuteness does come with a warning - feeding or touching them is prohibited to protect both species.