jtotheizzoe:

Forget the eagles. Bette Midler really should have sung “I can fly higher than a bar-headed goose.”

In last week’s It’s Okay To Be Smart, we looked at the amazing science of bird migrations. One of the birds I mentioned in that video, the bar-headed goose, takes the highest altitude migration of any bird that we know of, crossing over the Himalayas in order to reach their summer nesting grounds in India. Some climbers have reported geese flying overhead at more than 27,000 feet (8.2 km) above sea level!

Bar-headed geese have a few tricks up their feathery sleeves to accomplish this. They’ve evolved special hemoglobin that snatches oxygen extra-efficiently from the thin air, and grow capillaries that reach far into their hungry muscles. But it’s the respiratory systems of birds in general that are the real secret to flying high without passing out.

As you can see in the awesome animated GIF above from Rosemary Lutz (tabletopwhale), birds’ lungs are more like bagpipes than balloons, using a system of inflatable sacs and valves to move air through in only one direction. This keeps more oxygenated air passing near to their arteries compared to our more inefficient two-way breathing system.

For more on these ceiling-scraping, deep-breathing geese, check out this article from Audubon magazine.