The animal often referred to as the happiest animal in the world is the quokka Quokkas are small marsupials native to Australia particularly found on Rottnest Island and a few other smaller islands off the coast of Western Australia They are about the size of a domestic cat and have a stocky build with short rounded ears and a short tail Quokkas are known for their friendly and curious nature One of the main reasons they are dubbed the happiest animal is because of their facial structure which makes it look like they are always smiling This smile has made them very popular on social media where people love to take selfies with them Quokkas are herbivores primarily eating grasses leaves and stems They are nocturnal meaning they are most active during the night Despite their friendly appearance i t 's important to remember that they are wild animals