(Southern Double-wattled) What is a Cassowary?
The cassowary, looks like a giant prehistoric turkey walking on stilts with a large pointed helmet on its head. It is the second largest bird in the world. It is also the most dangerous bird on the planet. If threatened it will attack with a swift karate-kick with its powerful legs equipped with dagger-like claws.
This endangered dinosaur bird is a shy solitary animal that lives in the rainforests of northern Queensland in Australia.
With only 1,200 left in the wild, this endangered bird faces certain extinction. While the cute Kola gets all the attention, the oddball cassowary, which is actually far more endangered than the koala, gets little funding and attention. It may not be long before it too becomes extinct.
Cassowary is pronounced "cas-so-wary"
A cassowary can grow to nearly 2 meters and weigh up to 60 kilograms. The male and female cassowary is very similar in appearance. The female cassowary, however, is bigger, stronger and slightly more brightly coloured than the male.
Its has a long blue and purple feather-less neck with drooping red double wattles (the dangling bits like a turkey). The colour of its head and neck can change depending on the cassowary's mood. The exact nature of these colourations and their significance still is not understood by humans.
The cassowary has black, coarse glossy hair-like feathers. Its wings are tiny, having shrunk to the point of useless insignificance. These wings have no feathers, but instead have a few long, modified quills, like porcupine quills, which curve around its body. It also has no tail feathers. These characteristics are useful for pushing through the thick undergrowth without getting entangled in thorns and vines.
The cassowary has excellent eyesight with large forward-facing amber coloured eyes. Its hearing is excellent too, being specially adapted to hear the low frequency calls from other cassowaries.
The most prominent feather of the cassowary is the massive pointy helmet called a "casque" (pronounced like "cask") which sits on top of its head.
The cassowary has strong scaly legs, each with three toes. The inside toe has a dagger-shaped spike which is generally used for scratching the ground but it is also a lethal weapon for fighting and defending itself.
A Cassowary is quite agile and fast. It can sprint at speeds of up to 50 kph (30mph), even through thick forests. It can also jump as high as 2 meters m (6ft). It is a capable swimmer, crossing rivers and even swimming in the ocean. The cassowary's feathers aren't waterproof like most birds. So after a swim it shakes its body, much like a dog does, to get rid of water.
This bird has a lifespan of about 40 years in the wild and some in captivity have lived up to 60 years.
There are two explanations as to how this flightless bird got its name. One is that it is based on the French word "casque" which meaning helmet. The other is that is from words in the Papuan language - 'kasu' meaning horned and 'weri' meaning head. The second explanation seems more plausible given that this bird is also found in Papua New Guinea.
The cassowary found in Australia are known as the Southern Cassowary or Double-wattled Cassowary. This is to distinguish it from its relatives found on the island of New Guinea to the north which are referred to as the single-wattled cassowary.
Each cassowary wears a unique casque made of a sponge-like material covered with a thick outer layer of keratin – the same material our fingernails are made of. Although it looks solid, it is actually somewhat leathery and soft enough to be pressed.
Each casque, which has its own unique shape, grows throughout the animal's life. The size and shape of the casque is believed to be an indication of the animal's health, age and sex (the female has a slightly larger casque).
Inside the keratin outer sheath is a bony layer about 2-3mm thick beneath this is trabeculae (photo) which is porous spongy bone full of holey spaces. Beyond this is a large semi-hollow chamber with even more very delicate trabeculae with very fine blood vessels.
The purpose of this relatively large, odd-looking structure on top of the cassowary's head isn't fully understood. A number of hypothesis have been put forward for this unusual characteristic.
It's a Crash Helmet! — One suggestion is that it is a "crash helmet" to protect the animal's head as it travels through the dense rainforest. Given that it doesn't really seem to protect the cassowary's eyes and ears, the most vulnerable parts of its head, this is probably not its purpose. — unlikely
It's a Lethal Weapon — There is no evidence that the cassowary uses its head in fighting. Its casque is relatively weak and spongy and more likely to be seriously damaged in combat. — unlikely
It's a Tool — While the animal may use its head sometimes to knock down low hanging fruit or to shift leaf litter using its casque as a tool doesn't seem to be its primary purpose. — unlikely
It's a Fancy Headdress — Some have suggested that it is a fancy headdress to attract a mate. The casque, together with its colourful neck and wattles, may be intended to signal dominance, health and virility. There seems to be some truth in this, similar in manner to the way peacocks use their brightly coloured necks and tail feathers. — probably
It's an Amplifier and Receiver — The cassowary makes a very low-frequency booming sound. Some say that the casque acts like a sound-box to modify, amplifier and resonate the bird's sounds. These low-frequency sounds are better transmitted long distances through the thick forest vegetation. The casque may also act like a radar dish (receiver) assisting in picking up other cassowaries calls. — probably
Conclusion — The most likely reasons for the cassowary's casque is for display, as an amplifier to generate its low frequency sounds and as a radar dish to receive calls from other cassowaries.
The first indications you may get of the presence of a cassowary is a deep low-frequency rumbling and booming sound. It makes these sounds in its chest and neck by resonating air and then possibly amplifying the sound further with its casque. In fact, the cassowary produces the lowest sounding bird call in the world. These sounds can reach as low as 32 hertz which is just above the human hearing range. Some humans have claimed that they can actually feel the cassowaries low frequency boom resonating in their bones. It is claimed that a cassowary call can be heard up-to 5 kms away.
Cassowaries make a number of sounds. For example, when disturbed in its forest habitat, it may produce a low rumbling sound and clack its bills in an attempt the discourage you from approaching any closer. If it feels threatened it will puff itself up to its full height and make a hissing sound. If angered or ready to attack it produces a deep booming sound.
How a Cassowary Attacks
The Cassowary is a solitary animal that prefers avoiding confrontations, especially with humans. However, it is very brave and will stand its ground if approached. If an intruder encroaches on its space, the bird will stretch itself as tall as possible, ruffle its feathers and let out a loud hiss in an attempt to scare the intruder off. If this fails the cassowary will lower its head and produce a deep booming sound as the pigmentation of its skin on its neck becomes much brighter and its body trembles. It will then attack fearlessly.
The Cassowary has very powerful legs with dagger-like claws that look like spikes on its inner toes which grow up to 18cm in length. It attacks by jumping up in the air and kicking forward with its legs. Its lighting fast kick, with dagger sharp claws, is powerful enough to severely injure or even kill its victim. Once provoked it will keep up its attack chasing its victims at speeds up to 50 kilometers per hour.
Cassowaries have a reputation for being dangerous to people and domestic animals. Statistic show that this reputation is ill-founded. The last recorded death of a human due to a cassowary attack was in 1926. This too was in self-defence when a teenager attempted to attack a cassowary with a club.
Why Cassowaries Attack Humans
Of the 200 or so cassowary attacks reported in Australia each year, over 70% occurred while humans were attempting to feed these birds. This is because cassowaries become assertive and demanding when they associate humans with food handouts. So don't feed the cassowary!
The Southern Cassowary lives mostly amongst the dense vegetation of the rainforests of northern Queensland. It is a shy and solitary animal that is difficult to see amid the forest foliage. It is usually active during dawn and dusk and rests during the heat of the day. You are more likely to know of its presence by the deep booming sound its makes while moving about its habitat. Occasional cassowaries may also venture into mangrove forests, swamplands and even beaches close to their usual rainforest habitat.
These rainforest animals are territorial and will defend their home range vigorously. Their home territory is about 7 sq. kilometres and may vary from year to year depending on environmental factors.
Female territories sometimes overlap those of male cassowaries. Females are permitted to enter these male territories. This trespassing may be tolerated for two reasons. The most obvious being for mating. But a less obvious reason may be that the female cassowary is larger and more domineering than the male. So the male may be prudently avoiding a confrontation. If another male were to venture in, however, then the male owner would attempt defend its territory vigorously.
The Cassowary has a pointed beak but has no tongue. Because it doesn't have a tongue it must pick up its food with its beak and toss it back into its throat to swallow it. The cassowary drinks by scooping water with its lower bill. It also has a sharper sense of smell than most birds which makes it easier for this bird to locate food in leaf litter and in dense forest. A cassowary needs up to five kilograms of food a day.
It is a Frugivore (fruit-eater)
How the Cassowary Helps a Rare Tree Survive
The Ryparosa kurrangii is a rare tree found only in a very small area of the Daintree National Park in Queensland, Australia.
Recent scientific research has shown that only 4% of the seed from this tree self-germinate. However when it has been eaten and passes through the digestive tract of a cassowary the germination rate increases phenomenally to 92%. Similar results have been demonstrated with many over 120 other seeds too. It is obvious that without the cassowary's help, some of the oldest surviving rainforests in the world would be irrevocably changed forever.
The Cassowary is primarily a frugivore. Its diet consists mainly of fruits that have fallen to the rainforest floor. It also supplements this diet with leaves, fungus, insects, frogs, snakes and small animals. The bird usually eats in the morning and at dusk. It rests during the hottest part of the day.
Cassowary's Favourite Food
One of its favourite fruits is the Cassowary Plum. This large, blue fruit is poisonous to humans and most animals. The cassowary, however, loves eating it. It enjoys eating this fruit so much, in fact, that it will guard a tree that is dropping its fruit for days at a time until the tree stops shedding its fruit. The cassowary swallows the fruit whole. Its stomach contains rare of digestive enzymes that break down the poisonous alkaloids in the fruit making them harmless to this bird. This is very fortunate for the tree. The cassowary is the only animal large enough to swallow the entire fruit intact. It digests the fleshy pulp of the fruit and passes the seeds unharmed in large piles of dung. If not for this bird this tree would probably become very restricted in its habitat and may even become extinct.
Cassowary Digestive system
Cassowaries have a fairly primitive digestive system compared to other birds. They don't have a gizzard with stones and grit with which to grind their food. As a result they cannot extract the nutrition in seeds within a fruit. This characteristics of the cassowary's digestive system protects seeds and assists with seed dispersal over large areas of the rainforest.
Because of its seed dispersal function the cassowary is considered a "keystone species". Its loss from the ecosystem would significantly affect plant propagation in these tropical forests. Many seeds will only germinate once they have been passed through the digestive tract of a cassowary.
Cassowary dung, called a "scat", often containing hundreds, if not thousands of seeds. The dung helps many kinds of plants to propagate themselves. Other animals sometimes feed on seeds in cassowary droppings, helping to further distribute the seeds.
Cassowaries are solitary birds. They only come together to breed. Although cassowaries are capable of breeding throughout the year provided the environmental conditions are suitable, the peek breeding season is usually between June and November. The more dominate female will attract a male with her mating call and the display of her brightly coloured neck and wattles. The male will approach her cautiously, and if she views him favourably, he will dance in front of her to win her over. If she approves of him, the pair will spend at least month together courting and mating.
How Big are Cassowary Eggs? How much do they weigh?
The female cassowary lays between 3 to 8 bright green of blue-green eggs. Each egg is between10 to 16 centimetres in length an weight roughly 500 grams - the is half a kilo!
The female lays 3 to 8 large, bright green or pale-blue-green eggs, which measure about 9 by 14 centimetres in a nest made from leaf litter. Once the eggs are laid, she departs leaving the male to incubate the eggs. She may then mate with as many as three different males during the mating season.
The male guards and incubates the eggs for about 50 days. He feeds only rarely during this period and may loss as much as 30% of his body weight as a result. The chicks, when they hatch, are light brown in colour and have stripes which camouflages them very well amongst the leaf litter and protects them from predators. This colouring disappear as the chick grows.
Cassowary chicks do not have a casque, which only begins growing in juveniles when their plumage changes. The father looks after the chicks and teaches them the way of the rainforest.
The young chicks make a whistling-peeping sound as they run about. The father may respond by clacking its beak, burping or even by making a booming noise that cassowaries are renowned for.
After about nine months, by which time the chicks can fend for themselves, the father chases them away to go and find their own territory.
The mortality rate amongst cassowary offspring is very high. Usually only one in each brood survives into adulthood.
They reach sexual maturity at about three years.
To many people the Cassowary with its crested-head, brightly coloured neck, scaly legs and three-toed daggered feet conjures up images of a fearsome dinosaur - a two-legged theropod raptor, like the Velociraptor from the movie Jurassic Park. The cassowary almost looks like a living relic from the age of the dinosaurs.
Some Similarities between the Cassowary and Dinosaurs
Palaeontologists have discovered 77-million-year-old dinosaur nests which they believe belonged to Cassowary-like dinosaurs known as caenagnathid or dromaeosaurid. These dinosaurs shared many characteristics with modern birds such as feathers, hollow bones, nesting, egg-brooding and care for their young. Scientists believe that birds evolved from dinosaurs such as these. A number of ancient dinosaurs, such as the corythosaurus, a duck-billed dinosaur, had large crests on their heads similar to the cassowary.
So is a Cassowary really a dinosaur?
Strictly speaking "no" – Scientist are hesitant to claim that any modern animals are dinosaurs. Is it fair to say that a Cassowary is descended from dinosaurs? The answer is
"yes". Is it also fair to say that cassowaries are probably the closest living creature to a dinosaur? The answer is probably "yes".
The Cassowary belongs to a group of birds known as Ratites which also include the Ostrich, Emu, Kiwi and Rhea. Ratites began to evolve separately around 60 million years ago on the super-continent of Gondwana before it broke up into the continents of Africa, South America, Australia and Antarctica. This explains which ratites today are found in these continents. Their closest flying relative is the chicken-sized flight-capable tinamous of South America. Ratites are different from other birds in that they have a flat breastbone and are mostly large-bodied and terrestrial, that is they are rather big and they don't fly. Because they no longer fly, their wings have shrunk into non-functioning stubs. These birds also have a less sophisticated digestive system than modern birds.
Cassowary Conservation Status - Endangered The Cassowary is on the Australian Endangered Species List
It is estimated that the number of cassowaries living in the wild have declined by over 50% since 1988 to around 1,200 birds. The major cause of their decline is the result of human activity.
Large tracts of rainforest, home to these unique birds, has been chopped down for timber, banana and sugar-cane plantations and for urban developments. This destruction of the tropical rainforests and fragmentation of habitat is the primary cause of the decline of the cassowary population. Over 80% of the original Cassowary habitat has been lost since white settlement in Australia in 1788.
Each cassowary requires approximately 70-300 hectares of rainforest to survive. Cassowary chicks, when about nine months old, must find their own territory. In an ever-shrinking forest this has become near impossible. Only one in a usual clutch of four siblings survives into full adulthood.
The loss and fragmentation of their habitat has resulted in more cassowaries ventures near roads. Motor vehicle strikes account for about 50% of the annual cassowary death toll.
Human Hand Feeding
Feeding of cassowaries by humans encourages them to leave their natural habitat and lures them into suburban areas where they are more prone to vehicle strikes and dog attacks.
Venturing into suburbia makes these unique birds, especially the young birds, vulnerable to dog attacks. Attacks by dogs account for about 18% of annual cassowary deaths.
Wild pigs destroy cassowary nests and feed on their eggs. They also compete with the cassowary for food.
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