Meet the Adorable Quokka, Known as the 'Happiest Animal on Earth'

The quokka, an adorable marsupial hailing from southwestern Australia, is bound to put a smile on anyone’s face. They’re small and fuzzy, and the distinctive shape of their mouth gives quokkas the appearance of an ever-present grin. 

And despite their limited range, these herbivorous marsupials have captured the hearts of millions around the world — the viral #quokkaselfie trend on social media features thousands of selfies taken with quokkas.  

Yet as the quokka population rapidly declines, the lives of these viral sensations remain shrouded in mystery for many of their fans. Here’s what you need to know about the critters known as the “happiest animal on Earth” — and how scientists are working to keep them smiling.