24. Platypus
The platypus is a true oddity, not just in appearance but also in how it sleeps. This quirky mammal spends more time in REM sleep than any other mammal, often curled up snugly in its riverbank burrow.
Scientists are still unraveling the mysteries behind the platypus’s unique sleep cycles and what they reveal about mammalian evolution. Its puzzling patterns continue to fascinate researchers worldwide. Science Daily