How Toucans Use Their Bills to Keep Cool

Relative to body size, the Toco Toucan has the biggest bill of any bird in the world. And it's laced with blood vessels.

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.


This is BirdNote.

When summer sizzles, we look for ways to keep cool. Sip a cold one, turn up the air conditioning, or dress down to a pair of shorts and t-shirt. 

Birds lack these particular options. But in the case of the Toco Toucan of South America, evolution has come up with at least one alternative. 

Relative to its body size, the Toco Toucan has the largest bill of any bird in the world. It’s outsized, orange, and accounts for a full third of the body’s entire surface area. It’s also laced with blood vessels and has no insulation – features that make it a superb structure for getting rid of excess body heat. 

So blood pumps into the bill all the time. The hotter the weather, the farther out the blood goes. And the heat escapes through the bill’s thin outer layer. This thermal radiation works best when there’s a nice breeze, and the toucan can release virtually all its excess body heat. That means the Toco Toucan can stay cool even in the sweltering heat of the tropics. 



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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by Peter A. Hosner

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

Producer: John Kessler

Executive Producer: Sallie Bodie

 Narrator: Michael Stein

August 2018 

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