New clue in 200-year-old Cassowary mystery

WILDLIFE

Karlie Brady

Journalist

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The huge claw of a male Southern Cassowary looking very much the part of a modern day dinosaur. Image: Sarah Davis, ABC Landline.

The magnificent Cassowary is an icon of the rainforest and now researches at La Trobe University believe they may have solved a 200-year-old mystery surrounding the elusive bird.

A team of scientists have found new evidence that suggests the Cassowary’s distinctive helmet, called a casque, acts a heat regulator or “thermal window” to help the animal keep cool in hot weather.

Danielle Eastick, from La Trobe’s Department of Ecology, Environment, and Evolution, said there has been considerable curiosity and speculation surrounding the casque’s purpose for nearly two centuries.

“It’s really exciting to think we may have solved a mystery that has baffled scientists for so long,” Ms Eastick said.

“Our results are quite compelling and it’s highly probable this is what the casque is actually used for.”

Ms Eastick and her team used thermal imaging to test how the casque of 20 captive Cassowaries reacted in different temperatures.

The tests revealed that the birds released large amounts of heat from their casques when they were in hot weather, compared to much smaller amounts when in cooler climates.

“Just as humans sweat and dogs pant in hot weather or following exercise, cassowaries offload heat from their casque in order to survive. The hotter the ambient temperature, the more heat they release,” she said.

Rabecca Lynch, Wildlife Manager at the Habitat Port Douglas, said that this explanation appears to be logical.

“If you look at where these animals are found, here in North Queensland and up through Papua New Guinea, you're looking at an animal that lives in quite a hot climate, so it makes sense.

 

“I certainly think the casque is used for perhaps other reasons as well. It has been suggested that it helps to extend their vocalisations longer and further in the rainforest and also to help protect their head when moving through very thick rainforest.”

Ms Lynch said this type of research is significant because the Cassowary is an important part of the ecosystem, but largely due to human-related causes, their numbers are diminishing.

“Any research that we can obtain about this animal, for example, how we can help to take care of them, is always going to be of the utmost importance,” she said.


The “thermal window” explanation doesn’t just provide a rare insight into the Cassowary, but also gives us a glimpse of the make-up of dinosaurs, as it is believed many of the prehistoric animals may have also used the same technique.

“Many dinosaurs also had casques, so it’s possible they too helped keep cool this way,” Ms Eastick said.

The Cassowary certainly looks like the modern day dinosaur of the rainforest and Ms Lynch said that it is believed that birds and reptiles, such as the dinosaurs, do have a common ancestor.

The newly-discovered Corythoraptor jacobsi, a Late Cretaceous dinosaur found in China, sure looks to be the doppelganger of living cassowaries.

The animal is depicted as a Raptor-like creature, covered with feathers, and like the Cassowary, cannot fly, leading researchers to believe it may be possible that today’s flightless birds never did have flying ancestors.

Additionally, a new BBC documentary suggests that the Tyrannosaurus rex may have also looked more like the large bird rather than their well-known movie depictions. They may well have had feathers, scaly skin covered in dark blotches and brightly coloured, orange flashes directly above the eyes.

“There's a lot of similarities even now between birds and reptiles like scales on their feet for instance or their lightweight bodies,” Ms Lynch said.

“Cassowaries certainly look to be a living dinosaur, but they're not quite as prehistoric as we'd like to think.

“But if you look at those animals they do look like a living raptor, there's no doubt about it. With their long claws and the casque on their head, they are prehistoric looking,” she said.

Regardless of what their ancestry may be, one this is certain, the mysterious Cassowary is one of the Far North’s most recognisable icons. 

 

 

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