Birds are different from other animals. They have feathers. Obviously. They fly. Equally obvious.
Not so obvious: they have air sacs.
Ok what are air sacs? Little balloons in their bellies. And abdomen. And even in their bones (tiny ones of course).
What do they do? They hold air before and after it passes through the lungs.
How does that help? Air is pushed through the lungs in one direction rather than in and out like us.
And? Their lungs can extract more oxygen than ours.
Does that make them somehow better than us? I can't say. But one thing's for sure--I wouldn't make it across the Gulf of Mexico in a couple of nights without any rest or even a martini. :)
If you're interested, here's a cool little clip on YouTube which explains it simply in a delightfully British way.
