Daily Archives: 3 March 2019

Daintree’s Dinosaur. The cassowary.

Prefer to listen? Podcast available click here.

And here you are, on your journey of a life time travelling through the Daintree tropical rainforest section of the Great Barrier Reef Drive. You’ve crossed the River on the ferry, gone up and down the winding road over Alexandra range towards Cape Tribulation. And you’ve discovered intense green diversity – ancient ferns, woody vines, bright green foliage, steep drop-offs and running cascades. Just spectacular.

well camouflaged big birds at jungle edge
Camouflaged Dad and kid cassowary at jungle edge off Cape Tribulation Road

And suddenly you catch a glimpse of it from the corner of your eye – and your passenger gets excited by this big black shape moving slowly in the distance.

It’s your lucky day. Not everyone gets to see it. It’s our very big bird called the Southern cassowary, the Casuarius Casuarius — or just cassowary, for short.

So, what do you make of this living dinosaur, almost as heavy as Australia’s biggest living megafauna, the red kangaroo?

Well, it’s not going to hop, or fly anywhere. It’s a flightless bird and one of a group of mainly flightless birds called ratites that include the ostrich, emu, kiwis and the emas or rheas from South America. The DNA evidence also now informs us that a family of flightful birds (birds with flight) called Tinamou from South America are also related. Tinamous are sort of born-again flyers.

All adult cassowaries have a large mass of black feathers, making them almost invisible once they get a metre or two into the vegetation. The rest of their design is also adapted to heavy rainforest drudgery, with a solid body, short but massively strong legs, and three incredibly thick strong toes and vicious keratin toenails, the middle one more like steel.

If you get really lucky and come face to face with one of these elusive big birds you’ll notice their piercing, beady eyes; a big wide beak; a huge helmet or casque at the top of its head; and bright blue and red colouring around the wattle and neck. And you can get an idea of their age, because their drooping red double wattle grows longer and the casque grows larger.

Their fearsome beak swallows rather than bites food. One of our neighbours has seen an adult trying to come to grips with a full green papaya. It manoeuvred it around and around for minutes before finally – bang– squashing it with their big foot, then down the gullet! Problem solved.

Two teenage cassowaries hungrily fighting over a dead lizard
Normally frugivores, these teenage cassowaries are fighting over a dead lizard. Opportunistic omnivores.

Cassowaries are mainly fruit eaters, with some flowers and fungi often thrown in for good measure, depending on the seasonal food supply. But, frankly, when they have the chance, they get very excited with a meal of dead meat (or carrion); or small live birds, insects and reptiles. A few years ago, I saw an emerald dove get too close to an adult cassowary. Big mistake! A few pecks, and then it fed the proceeds to its enthusiastic chicks. I guess that makes it an opportunistic omnivore.

When you are out and about exploring the Daintree boardwalks or just casually strolling from your rainforest accommodation, don’t just look for the big black shape to find evidence of this unusual big chook. Keep an eye out for the big sometimes colourful blobs they leave behind in their travels.

What are these big blobs? Cassowaries have no teeth, so they swallow their fruit whole. Then their highly acidic digestive juices and strong muscular organs called gizzards take over and grind up the food, separating the flesh from the seeds. The final product is a ready-to-grow mixture of seeds and manure which is soon pooped out as a big blob. Look out for it and examine its contents. This seed-nurturing skill makes cassowaries key agents in spreading large seeds through the rainforest.

Don’t bother searching for their rough shallow nest. It’ll be well hidden away from the roads and walking tracks. Of course, its up to Mum to lay the green-coloured eggs, usually 3 to 6 in a nest, but it’s the very modern Dad that does the heavy lifting. This means sitting on the eggs, and later raising the young.

The eggs hatch after about 60 days, when the hatchlings are called “stripeys”. After a few months, the young

Three young stripeys -- cassowary chicks
Very young cassowary chicks are called “stripeys”.

teenagers change to a dull brown. When the young become a bit older, locals often see Mum joining the family from time to time, but any crisis has the kids quickly scampering back to Dad.

Now, when the kids are around 9 months, at times up to a year later, Dad or Mum or both need to make a life-changing decision.

An adult female would have had a good look around at the available talent, and selected the youngsters’ Dad to sit on her next clutch of eggs. (It helps that she’s 40% bigger than the Dad. Size is important in the cassowary world).

It might take a while but once the new union is established, Mum and Dad may actually join forces to kick the young out of home.

Like many instances in the bird world, separation can at times be brutal. One of our local lodge owners reported an adult hiding behind a tree, jumping out, and chasing, pecking and even kicking at the young until …success. The youngster is finally, reluctantly, out on its own. It’s tough love.

We’ve also heard that when Dad thinks its time for the young birds to have their own life, he’ll try to sneak out of the scene quietly, and who knows how strongly he might respond to any attempt to reconnect?

In the wild, it’s rare for even one stripey to reach maturity and have its own young. Tough love in a tough world!

The idea of all those big toes hanging around in the forest, could make one feel a bit uneasy about the prospect of an encounter. Really, there’s no need to panic.
It’s very safe, as long as you don’t act in a way that feels threatening to the cassowary.

They’re quite happy doing their own thing, unless threatened or provoked. Avoid situations like jumping out of a car, getting between them and the chick, having a dog present, or even just panicking and running away from it. So stay in your car, don’t get between dad and chicks, move slowly backwards and be respectful!

Originating from dinosaurs, as a megafauna survivor, cassowaries are well equipped to defend themselves vigorously! Firstly, they’re very quick. Their big pecking beaks can hurt, their feet are fearsome and those dinosaur-like toes are vary sharp. They can either jump vertically or hurl themselves sideways to strike at a passing car, an attacking dog, or – as we mentioned before – even its own young.

If you stay around long enough, you’ll probably come to realise that virtually all encounters are happy and harmless, and show the remarkable curiosity of the cassowary. Many locals, working intently at a work bench, or in the garden, have suddenly sensed a cassowary companion peering over their shoulder. A bit spooky, but just relax, mate, and keep your head down!

There’s still a lot we don’t know about the cassowary, like why do have that huge casque or helmet on its head? The early naturalists and collectors thought that the casque was a hard bony helmet.We now know that it is not the case. The casque is actually quite light, soft and flexible. The outside cover is a keratin sheaf. Keratin, by the way, is what fingernails and claws are made of. Inside the casque are thin cellular bony structures and empty space, not liquid.

Injured beak adult cassowary with large bent casque
Male cassowary with soft keratin casque, fruit swallowing beak, injured nose.

This means that the old ideas about their purpose can be dismissed pretty easily.
The casque is not used as a battering ram through the dense rainforest and also not used to knock fruit or food off branches, nor to head butt each other.
The scientists now are discussing three current theories. Some propose that the casque is a sociosexual attraction, indicating fitness, maturity and vigour.

Another suggestion is that the casque provides a drumlike sonic boom, a sort of low frequency voice box, allowing sound to travel longer distances through the dense forest, also a sociosexual idea.

Most recently, it was demonstrated that the cassowary casque actually helps with temperature control, and loses a little bit of heat in cool weather but a lot more in hotter weather. The idea was first raised in 1994 –and was comprehensively measured quite recently by Danielle Eastick from La Trobe University, using a hand held thermal imagery device.

So, three modern theories, but the jury’s definitely still out as to which of these might be primary or secondary purposes in the cassowary casque’s evolution.

Cassowaries evolved as rainforest specialists, and in tropical rainforests it rains a lot in the wet season. That’s what creates all these beautiful postcard-like creeks.
So, not only can they run fast through the thick vegetation, but they can also swim, and can cross deep streams, if they have to. Of course, they also need to drink and love to cool off in water.

Pair of cassowaries enjoying cooling off in water
Cassowaries can swim, cool off and some even fish!

And some of them are known to go fishing, without the rod and any other gear! They’ve been seen to settle down in a creek with their feathers spread out – until innocent little fish take refuge under their plumage. The cassowary then clenches its feathers, gets out of the water, shakes itself to release the fish, and eats the catch. Remarkable, maybe rare and localised, but true!

So, how many cassowaries do we have in Australia?

The most comprehensive research (Reef and Rainforest Research Centre in 2014) indicates about 4,400 cassowaries in the Wet Tropics, spread over 23 sub-regions, with a stable population over the last 20-30 years. We know that there are more in the northern part of Cape York, but their numbers have never been counted.

Most live in inaccessible rainforest around Tully and the Russell River, south of Cairns.
Between the Daintree and Bloomfield rivers, the numbers are around 110! Luckily for visitors, these are along a narrow strip of road between the Coral Sea and the mountains, so we often get to see and appreciate them!! So, if you come across a Dad with two chicks, you’ve seen about 3% of the local population.

That’s a brief introduction to our big birds. Cassowaries are so fascinating and unusual, that we’ll need another Podcast and Blog to answer your questions. So, if you have any more questions or information, please send them to us.

When you visit the Daintree, make sure that you stay around for a few nights to get the full rainforest experience. Stay longer. See more. Maximise your chance of spotting a cassowary.