Birds Breathe Through Hollow Organs

Birds do not have a diaphragm like mammals; instead, they use complex air sacs throughout their bodies to circulate oxygen. These delicate structures are highly susceptible to infection, leading to a condition called airsacculitis.

Unlike our simple lungs, bird anatomy relies on a system of thin-walled sacs that act like bellows to keep air moving constantly. Because these sacs spread deep into the bird's bones and body cavity, a tiny bacterial infection can quickly become a systemic issue. This makes birds uniquely vulnerable to respiratory diseases that travel through their entire internal architecture. It is a fascinating but fragile trade-off for the extreme energy demands of flight.