July 24, 2009

Study says toucan’s bill sheds heat

The toucan's large bill helps it release heat when the colorful bird's body becomes too warm, researchers at Canada's Brock University said.

Scientists, including Charles Darwin, traditionally believed the toucan's bill helped attract mates, peel fruit or act as territorial weapons and visual warnings to predators, Brock researcher Glenn Tattersall said in a release Thursday.

The toucan has the largest bill of any bird, relative to body size, its bill comprising about one-third of its total body length.

Tattersall's team photographed captive toucans with infrared cameras, which showed the toucans' bills acted as a thermal window glowing with radiated heat as warm blood flooded the uninsulated bills during hot weather.

In cooler weather, little heat radiated from their bills, letting the toucans conserve heat, he said.

Writing in the journal Science, Tattersall's team concluded the toucan's bill releases excess heat in a variation of what humans do when they sweat and what dogs do when they pant.