We humans aren’t the only creatures with lungs.
All mammals have them, from the tiny bumblebee bat to the great blue whale. So do spiders, lizards, frogs, and many other creatures. But birds have the most efficient lungs by far.
Human lungs fill and empty like balloons. Birds’ lungs don’t. They give birds a steady, constant flow of air. It’s no wonder birds can soar to the top of Mount Everest, where the air is thin. Most humans need tanks of oxygen to hike there.
