Did You Turn the Heat Up?

Stop me if you've heard this one.

An HVAC consultant says to the toucan "It's gonna cost you a good chunk of change to keep cool this summer." Toucan says "Meh. Just put it on my bill."

And that's precisely what evolutionary adaptation did.

Long a source of puzzlement to scientists going back to Charles Darwin and up through those in the field of evolutionary biology that has developed since Darwin, the enormous bill sported by the toucan turns out to serve the same function as the elephant's large ears. They serve to dissipate heat, and keep the animal cool.

Publishing findings in the current issue of the journal Science, evolutionary physiologist Glenn Tattersall of Canada's Brock University in Canada studied a species of South American toucan whose enormous bill represents from one third to one half of its total surface area.

Temperature measurements of surrounding air and of the bird itself (both at rest and in flight) determined that heat loss through the bill accounted for a minimum of 5 percent at lower temperatures and lower levels of activity. Heat loss of up to 100 percent of the animal's cooling was observed at higher air temperatures and higher levels of activity such as flight.

By controlling blood flow to its beak, the toucan is able to regulate its internal temperature according to the weather and to its own activity level in what the research shows to be among the most efficient body temperature regulation known to the animal kingdom.

Photo courtesy of Roy&Danielle, via Wikimedia Commons.