February 14 (UPI) – For 200 years, scientists have been trying to understand the role of helmet-like hornbill, which protrudes from the top of the southern casoary's head.
Thanks to new research from the University of La Trobe, the mystery of the helmet is solved.
Scientists have determined that the helmet functions as a "thermal window". The hornbill causes and expels excess body heat, thus helping iconic Australian species to stay cool during the summer heat.
"Our results are quite convincing and it is highly likely that the helmet is actually used," said ecologist Danielle Eastick in a press release. "It's really exciting to think that we may have solved a mystery that has long confused scientists."
For the study, Eastick used a thermal imaging device to observe the helmets of 20 captive cassowaries. When the weather was cooler, the images showed that only small amounts of heat were measured in the helmets. When the weather warmed up, higher concentrations of thermal energy were recorded in the helmets.
Native to northern Queensland and Papua New Guinea, the southern casowary, Casuarius casuarius, is used for hot weather. But the big bird with black feathers is also vulnerable to overheating. The helmet helps the cassowary to stay cool during the summer heat waves.
Last month, Australia set a new record for night records – 96.6 degrees Fahrenheit – and research suggests that extreme heat threatens a variety of species, Down Under.
"Just as humans sweat and dogs pant in warm weather or after exercise, casinos discharge heat from their helmets in order to survive," Eastick said. "The higher the ambient temperature, the more heat they give off."
The researchers published their analysis of casoar helmets in the journal Scientific Reports.
If the explanation of the "thermal window" is accurate, the casoar helmets could offer new information on the physiology of dinosaurs.
"Many dinosaurs also had helmets, so it's possible that they also helped keep cool in this way," Eastick said.