This audio story is brought to you by BirdNote, a partner of The National Audubon Society. BirdNote episodes air daily on public radio stations nationwide.

birdheartaudio

Transcript:

This is BirdNote.

Birds, like mammals, are warm-blooded. It’s an adaptation known as endothermy. Along with feathers and other key anatomical features, endothermy is a fundamental trait carried over from their non-avian dinosaur ancestors, active hunters known as theropods, like the fearsome Velociraptor or the T. Rex.

Birds’ bodies maintain a constant temperature, around 106 degrees. Their four-chambered hearts run larger than those of mammals, relative to body size, and they’re coupled with extremely efficient cardiovascular systems. 

Birds are built for a high-energy lifestyle. Their hearts pump more oxygen-rich blood per minute than those of mammals. The energy demands of flight require it. And smaller animals lose body heat more rapidly, burning the oxygen in their blood faster than larger animals.

An active hummingbird’s heart pumps at 1,200 beats per minute; a flying pigeon’s heart beats at 600.

But a human athlete during exercise builds up a heart rate to around only 150 beats, a mere fraction of the hummingbird’s heart rate.

Exercise as hard as you like. Your heart will stay in the slow lane compared to that of a bird.

For BirdNote, I’m Michael Stein.

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Credits:

Written by: Bob Sundstrom
Narrator: Michael Stein
Senior Producer: John Kessler
Production Manager: Allison Wilson
Producer: Mark Bramhill
Associate Producer: Ellen Blackstone
Digital Producer: Conor Gearin

Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Pileated Woodpecker recorded by N. Pieplow, Carolina Chickadee recorded by N. Pieplow, Broad-tailed Hummingbird recorded by R. Stein, and Broad-tailed Hummingbird recorded by G. Keller.

BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.

© 2021 BirdNote    November 2021 

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