A team of Melbourne scientists is now claiming to have cracked the case – and their answer could also be for a set of dinosaurs with similar skull structures.
Using thermal imaging, they proved that casinos are being used as, for example, the radiator in the car to keep the casers in the sticky warmth of the tropics.
Daniel Istik, Leading Lead Author Scientific reports said that birds face a significant "heat challenge". They are covered in dark feathers, live in hot and humid environments in North Australia and New Guinea and are large and heavy – the females can grow up to two meters and weigh 76 kilograms.
"Animals that can not be swallowed should use other mechanisms to unload excess heat," said Mrs. Istik, a La Trobe University researcher.
Dogs suffocate, kangaroos lick their hands, and elephants use their huge ears as radiators.
Birds can use other parts of their bodies – often their mouths – as "thermal windows".
For this reason, tropical birds often have larger accounts than those in the cooler climates.
They can also use wings, but even when compared to a cousin who was not in flight, the wings of the case are small.
Made of keratin – which also builds nails and rhinoceroses – the horns have a wide network of blood vessels. As the temperature rises, the vessels expand, allowing more blood to enter the thin and non-insulated coat of arms.
"So what the casuurs are doing is pumping a lot of blood into the cash box where it is cooled by the air outside," says Mrs. Istik.
The chilled blood is then pumped back into the body. Conversely, when the temperature drops, the blood vessels shrink, interrupting the blood flow to the pulp.
"So they hold the warm blood in their body instead of losing that heat.
Mrs. Istik said that the explanation for the "thermal window" could also apply to dinosaurs, many of whom had "really similar structures" of the case studies.
Although the findings finally shed light on the cash-box system, they do not exclude the possibility of other functions.
Joe Hinckley reports on The Age.