Useless Wings But Better Lungs

penguins_flying.jpgA special post from Alison Boyer whose research encompasses birds and body size evolution.

Penguins are remarkable divers, capable of diving to depths exceeding 200m. The largest penguin species, Emperor penguins (Aptenodytes forsteri), have been recorded diving to 535m and can hold their breath for 15 minutes while actively swimming. Generally, small-bodied vertebrates are limited to shallow diving depths because they are restricted in the amount of oxygen they can store while diving. Penguins partially overcome this limitation with their unique respiratory system. When humans (and other mammals) breathe, our lungs conduct air in and out of the same set of tubes, known as tidal breathing. This means that our lungs are not terribly efficient at extracting oxygen from each breath before exhaling. Penguin lungs, however, have one-way air flow. When a penguin takes a breath, the air moves into a system of air sacs. From there, the air moves through the lungs and into other air sacs until it is exhaled. It it thought that penguins closely regulate the flow of air through the lungs while diving to provide a constant supply of oxygen to the body. In addition, the lung and air sac system is important in regulating buoyancy during dives.

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Dr. M (1729 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, a National Science Foundation supported initiative. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (, a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web. His forthcoming book, Science of the South (, connects cultural icons of South such as pecan pie with the science behind them.

One comment on “Useless Wings But Better Lungs
  1. Great website Alison! I’ve been crazy about penguins for years, but had never seen this site before. I worked at the Monterey Bay Aquarium for a year and half as volunteer penguin caretaker. Fascinating birds!


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