In the heat of summer, air-conditioned humans complain about electricity bills. A new study suggests that a toucan’s huge bill relates to its air-conditioning costs, too. The eighteenth-century French naturalist Georges-Louis Leclerc, Comte de Buffon, famously described the toucan’s beak as “grossly monstrous.” Charles Darwin thought it might serve a sexual selection function, and the question has intrigued biologists ever since.
In a July 2009 article in Science, Glenn Tattersall of Brock University and colleagues at the Universidade Estadual Paulista suggest that the oversized bill releases heat. They used an infrared camera to record the heat emanating from a Toco Toucan’s bill as the bird fell asleep. They found that the bird could regulate heat loss by modifying the blood flow to the bill. The authors also found that the bill effectively dissipates heat as the toucans fly.
The authors conclude, “Our results indicate that the toucan’s bill is, relative to its size, one of the largest thermal windows in the animal kingdom, rivaling elephants’ ears in its ability to radiate body heat.”