The huge and colorful bills of the Toucan bird has long fascinated scientists. It’s the largest bill of any bird and even Charles Darwin pondered it’s function. Now new research suggests the birds use it to regulate their body temperature:
Accounting for 30% to 50% of the body’s surface area and about one-third of its length, the colorful bill has many blood vessels and is not insulated. These factors, contend the authors of a new study, make the beak well-suited to regulate body temperature.
In the study, published in Friday’s issue of the journal Science, researchers placed four adult and two juvenile toucans at separate times in a chamber, changing the air temperature in increments from 50 to 95 degrees Fahrenheit. Infrared thermal imaging technology was used to determine surface temperature of the birds’ bills. By comparing the temperatures of the bill and the chamber, they calculated heat loss from the bill.
The study’s conclusions: As the birds’ surroundings heat up, blood flow increases to their bills. There, heat carried by the blood is radiated into the air, cooling the body. At lower temperatures, blood flow to the bill decreases. Less heat is lost, and the toucan is able to keep warm.
Birds can’t sweat so they have to rely on some other method of heat regulation. Having a bill with a large surface area and lots of blood vessels would allow Toucans to do just that. More research needs to be done to confirm the findings, but it’s possible one of the bigger bird mysteries may finally be solved.