How Do Birds Breathe?

This week my second oldest grandson ask me what a one-way breath loop was. My first response was, what? (They are getting too smart!) I had to look it up. I found out it was related to the way birds breathe. I’ve taught biology for years and never paid any attention to it. I mean, birds have lungs so they breathe in and breathe out. No big deal right?

Turns out, it’s a huge deal. Whereas humans and other mammals breathe in to fill their lungs and breathe out to empty them reversing the flow each time, birds on the other hand keep air going through the system in one direction all the time. It means there is fresh air constantly flowing through their lungs all the time. They do this by using a series of air sacks that keep the air moving through their lungs. Only after it goes through the whole circuit does it get exhaled.

Birds need this system because they need extra oxygen to fly and they also may spend a lot of time at higher altitudes where the air is thinner. They also breathe many times faster than most mammals. Smaller birds like canaries may breathe 60-100 times a minute! Larger soaring birds like vultures may only breathe 18 times per minute. (Humans average 12.)

According to https://www.birdfact.com/articles/how-do-birds-breathe:

A bird takes two breaths to complete one full cycle of breathing. Here’s a summary of how it works:

Inhalation: Air flows in through the nostrils, moves through the trachea, and fills the posterior air sacs.

Exhalation: Air leaves the posterior air sacs and travels into the lungs, moved by the contraction of muscles in the ribcage. Gaseous exchange takes place in the lungs, where the waste carbon dioxide is swapped for fresh oxygen.

Inhalation: Air leaves the lungs, flowing into the anterior air sacs.

Exhalation: Air passes from the anterior air sacs into the trachea, leaving the beak through the nostrils.

That seems like a lot of work, but if you are a bird, you need it. Isn’t it amazing how God has given each creature the things they need to survive? He sure is a great designer!

Well, my head is spinning from all that science stuff. Until next time!

Love Papaw.