Jay Ingram - The Science of Why, Volume 3: Answers to Questions About Science Myths, Mysteries, and Marvels

Also by Jay Ingram

The Science of Why2: Answers to Questions About the Universe, the Unknown, and Ourselves

The Science of Why: Answers to Questions About the World Around Us

The End of Memory: A Natural History of Aging and Alzheimers

Fatal Flaws: How a Misfolded Protein Baffled Scientists and Changed the Way We Look at the Brain

Theatre of the Mind: Raising the Curtain on Consciousness

Daily Planet: The Ultimate Book of Everyday Science

The Daily Planet Book of Cool Ideas: Global Warming and What People Are Doing About It

The Science of Everyday Life

The Velocity of Honey: And More Science of Everyday Life

The Barmaids Brain and Other Strange Tales from Science

The Burning House: Unlocking the Mysteries of the Brain

A Kids Guide to the Brain

Talk Talk Talk: Decoding the Mysteries of Speech

Its All in Your Brain

Real Live Science: Top Scientists Present Amazing Activities Any Kid Can Do

Amazing Investigations: Twins

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Library and Archives Canada Cataloguing in Publication

Ingram, Jay, author

The science of why, Volume 3: answers to questions about science myths, mysteries, and marvels / Jay Ingram.

Issued in print and electronic formats.

ISBN 978-1-5082-5795-0 (hardcover).ISBN 978-1-5082-5796-7 (ebook)

1. SciencePopular works. 2. ScienceMiscellanea. I. Title.

Q162.I553 2018 500C2018-902297-3

C2018-902298-1

ISBN 978-1-5082-5795-0

ISBN 978-1-5082-5796-7 (ebook)

This book is for Oscar Alexander Quinlan, even though I doubt hell read it for a few years

T HIS QUESTION REALLY HAS TWO PARTS: WHY AND HOW? Even if you can come up with a good reason that a two-legged creature would spend time on one leg, theres still the issue of how it could do that for lengthy periods of time. If you dont think thats difficult, try standing on one leg, sticking your arms out sideways, then closing your eyes. Not easy!

Not all birds stand on one legmostly its the long-legged ones, like cranes, storks, and especially flamingos. More often than not, because these birds spend a fair amount of time feeding in oceans, lakes, and rivers, the standing leg is submerged in water. And this has led scientists to think about heat loss.

Birds use a trick of anatomy to minimize the loss of body heat through their feet and legs. The arteries carrying warm blood to their feet are adjacent to veins bringing blood that has been cooled by exposure to the cold airor in this case, waterback into the body. The warm and cool blood exchange heat, ensuring that the blood entering the birds body is warmer than it would have been, thus reducing the amount of heat loss and minimizing the energy the bird has to put into maintaining its body temperature.

You dont have to put a bird in the lab to see this: ducks and gulls do not leave footprints when they stand on ice or snow. Their feet are too cool to do that.

Its not a bad system, but some studies have shown that heat loss in the water is four times greater than in the air, so perhaps standing on one leg would be a help. Instead of two legs returning cool blood to the body, there would be only one, with the other tucked in under the body to keep it warm.

With that thinking in mind, Matthew Anderson at St. Josephs University in Philadelphia observed captive flamingos at the Philadelphia Zoo to get a better picture of whats going on. He and his colleagues found that flamingos were much more likely to stand on one leg if they were standing in water rather than on land. Anderson interpreted this to mean that the birds were doing so to reduce cooling. And further experiments showed that this was true: the lower the temperature, the more time the birds spent on one leg.

If its true that flamingos stand on one leg to minimize heat loss, then when the weather is very warm you might expect theyd prefer to stand on both legs to cool down. Thats exactly what Anderson found. Anderson and his colleagues also found that flamingos exhibited no preference for one foot over the other, even though other birds, like curlews and avocets, seem to prefer standing on their right foot.

Science Fact ! Flamingos have a preference for turning their head to the right when they lay their head, in an S curve, on their back.

So the prevailing opinion right now is that birds like flamingos stand on one leg to minimize heat loss. But isnt it difficult to balance like this? In a very cool study at the Georgia Institute of Technology, Young-Hui Chang and Lena Ting showed that the flamingo is beautifully adapted to stand on one leg, without any effort!

They started their investigation at least partly because theres a potential drawback to standing on one leg to stay warmer. If it requires constant adjusting of muscles to maintain balance, the energy expenditure might be too much to justify the one-legged stance.

Ting and Chang experimented both with the bodies of two dead flamingos and with a selection of live birds to identify the demands of one-leggedness. This is easier to understand when you know that birds like flamingos actually stand on their toes. What looks like a backward-bending knee is really the ankle, and the knee joint is usually hidden by the feathers of the body. Higher up, the thighbone, unlike ours, is positioned almost horizontally. So when they are standing, theyre sort of crouching.

Even a dead flamingo can do this. The researchers found that when the bird was positioned on one leg, with its center of gravity just in front of the knee (which is tucked up into the body), the joints, especially the knee and hip, lock into place, and can support the weight of the bird easily. A living bird would have to exert very little, if any, effort to stay stable in this position.

Chang and Ting met a couple of surprises along the way. First, they were sure that they knew which muscle groups were engaged when the birds stood on one leg. So they set up a high-speed camera to witness the collapse of the dead bird when they severed the muscle. But the bird didnt budge! Then when Chang hoisted the dead flamingo into the air by the shin, the leg snapped into its rigid position like a tent pole.