image: The toucan's bill is a vascularized structure that can also act as a radiator of heat. As revealed from thermal imaging, toucans can restrict blood flow to the bill when cold, and when warm, can increase blood flow to facilitate removal of endogenously generated heat. Juvenile toucans, investing heavily in bill growth, however, are unable to make these adjustments, demonstrating that the bill is a significant source of heat loss in the bird during development. This image accompanied the research article "Heat Exchange from the Toucan Bill Reveals a Controllable Vascular Thermal Radiator," by G.J. Tattersall et al. appearing in the July 24, 2009, issue of Science. view more
Credit: Image courtesy of Glenn Tattersall