For centuries, scientists have puzzled over why the toucan's bill is so remarkably large - but now one team thinks it might have an answer.
Writing in the journal Science, the researchers say that the toucan uses its enormous beak to stay cool.
They used infrared cameras to show the bird dumping heat from its body into its bill, helping it to regulate its body temperature.
The toucan has the largest bill of any bird, relative to body size.
It makes up about one-third of its total body length.