How does birds breathe

When a bird exhales that same breath, it does not leave the body as it does with mammals but rather moves into the lung where oxygen is absorbed and carbon dioxide expelled. When a bird inhales for the second time, that same breath of air moves from the lungs into the anterior air sacs. Every breath a bird takes requires two breathing cycles to complete a single breath, making the air passing through the lung unidirectional and always fresh and full of oxygen.

Bird lungs are small and rigid, with the gas exchange region of their anatomy organized into a series of parallel tubes that bring deoxygenated blood into the lung at the opposite direction the air is flowing. Everest without issue. Birds, however, lack the heat-dissipating sweat glands that we possess. Remember that sweat glands cool by producing a salty secretion that evaporates from the skin.

The heat required to change sweat from a liquid to a vapor comes from the skin, thereby cooling it. Birds change water into vapor in a similar way in the air sacs, except that the heat required to vaporize the water comes from organs and tissues surrounding the air sacs.

And the air sacs help regulate temperature by providing a mechanism to dissipate excess body heat. The system is yet another example of the amazing biology of birds. New to BirdWatching? Sign up for our free e-newsletter to receive news, photos of birds, attracting and ID tips, descriptions of birding hotspots, and more delivered to your inbox every other week.

Sign up for our free e-newsletter to receive news, photos of birds, attracting and ID tips, and more delivered to your inbox. Colleagues and former students at Hope College share memories of Eldon Greij involving birds, road trips, tacos, fish fries, and more. Skip to content Become a member and get exclusive access to articles, contests and more! Illustration by Elisabeth Rowan.

Sign up now See the contents of our current issue How to subscribe to BirdWatching. Read our newsletter! Sign Up for Free. Stay in touch with BirdWatching Keep up to date on all the latest birding news and info. The study, conducted by researchers at New York University and the New Jersey Institute of Technology, also points to smarter ways to pump fluids and control flows in applications such as respiratory ventilators.

The one-way flow of air in birds' breathing systems was discovered a century ago. But what had remained a mystery was an explanation of the aerodynamics behind this efficient breathing system.