When extreme sleepiness strikes, it can feel impossible to keep your eyes open. Unfortunately, for us humans, we usually have to fight the urge to curl up into a ball and dream the day away. Jobs and responsibilities get in the way.But these adorable animals know it's better to simply give in to their fatigue - anywhere and at any time. They power nap harder than your grandpa after Thanksgiving dinner. 1. "Sorry, too sleepy for walks in the park." Imgur 2. He was too tired to put his head on his bed. Imgur 3. I've heard of sleeping like...