Cassowary facts for kids

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Cassowary
Temporal range: Pliocene to present
Southern Cassowary at Jurong Bird Park, Singapore
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Casuariiformes
Family: Casuariidae
Genus: Casuarius
Brisson, 1760
Species

Casuarius casuarius
Southern Cassowary
Casuarius unappendiculatus
Northern Cassowary
Casuarius bennetti
Dwarf Cassowary
Casuarius lydekki

The cassowaries are ratites, very large flightless birds in the genus Casuarius native to the tropical forests of New Guinea and nearby islands. There are three extant species recognized today. The most common of these, the Southern Cassowary, is the third tallest and second heaviest living bird, smaller only than the ostrich and emu.

Cassowaries feed mainly on fruit, although all species are truly omnivorous and will take a range of other plant food including shoots, grass seeds, and fungi in addition to invertebrates and small vertebrates. Cassowaries are very shy, but when disturbed, they are capable of inflicting serious injuries to dogs and people. Cassowaries (Casuarius) are a kind of large birds which cannot fly. They are part of a group of flightless birds called the ratites. The ostrich, emu, moa (now extinct) and small kiwi are other ratites.

The cassowary lives in the tropical rainforests of New Guinea and north eastern Australia. They are shy birds living deep in the forest. They can also become angry, and they will attack people. This makes it hard to learn about them.

Description

The Northern and Dwarf Cassowaries are not well known. All cassowaries are usually shy birds of the deep forest, adept at disappearing long before a human knows they are there. Even the more accessible Southern Cassowary of the far north Queensland rain forests is not well understood.

Females are bigger and more brightly colored. Adult Southern Cassowaries are 1.5 to 1.8 metres (4.9–5.9 ft) tall, although some females may reach 2 metres (6.6 ft), and weigh 58.5 kilograms (129 lb).

All cassowaries have feathers that consist of a shaft and loose barbules. They do not have retrices (tail feathers) or a preen gland. Cassowaries have small wings with 5-6 large remeges. These are reduced to stiff, keratinous quills, like porcupine quills, with no barbs. A claw is on each second finger. The furcula and coracoid are degenerate, and their palatal bones and sphenoid bones touch each other. These, along with their wedge-shaped body, are thought to be adaptations to ward off vines, thorns and saw-edged leaves, allowing them to run quickly through the rainforest.

A cassowary's three-toed feet have sharp claws. The second toe, the inner one in the medial position, sports a dagger-like claw that is 125 millimetres (5 in) long. This claw is particularly fearsome since cassowaries sometimes kick humans and animals with their enormously powerful legs (see Cassowary Attacks, below). Cassowaries can run up to 50 km/h (31 mph) through the dense forest. They can jump up to 1.5 metres (4.9 ft) and they are good swimmers, crossing wide rivers and swimming in the sea as well.

Cassowary head frontal
Detail of a Southern Cassowary head.

All three species have horn-like but soft and spongy crests called casques on their heads, up to 18 cm (7 in). These consist of "a keratinous skin over a core of firm, cellular foam-like material". Several purposes for the casques have been proposed. One possibility is that they are secondary sexual characteristics. Other suggestions include that they are used to batter through underbrush, as a weapon for dominance disputes, or as a tool for pushing aside leaf litter during foraging. The latter three are disputed by biologist Andrew Mack, whose personal observation suggests that the casque amplifies deep sounds. However, the earlier article by Crome and Moore says that the birds do lower their heads when they are running "full tilt through the vegetation, brushing saplings aside and occasionally careening into small trees. The casque would help protect the skull from such collisions." From an engineering perspective the wedge shaped casque is also the most efficient way to protect the head by deflecting falling fruit. As cassowaries live on fallen fruit they spend a lot of time under trees where seeds the size of golfballs or larger are dropping from heights of up to 30 metres. Mack and Jones also speculate that the casques play a role in either sound reception or acoustic communication. This is related to their discovery that at least the Dwarf Cassowary and Southern Cassowary produce very-low frequency sounds, which may aid in communication in dense rainforest. This "boom" is the lowest known bird call, and is on the edge of human hearing.

The average lifespan of wild cassowaries is believed to be about 40 to 50 years.

Behaviour

Cassowaries are solitary birds except during courtship, egg-laying, and sometimes around ample food supplies. Male cassowaries defend a territory of about 7 square kilometres (1,700 acres) for itself and its mate, while females have overlapping territories of several males.

Casuarius casuarius -Brevard Zoo-8a
Southern Cassowary at Brevard Zoo, USA

Reproductive

The breeding season starts in May or June. Females lay three to eight large, dark bright green or pale green-blue eggs in each clutch into a prepared heap of leaf litter. These eggs measure about 9 by 14 centimetres (3.5 by 5.5 in) — only Ostrich and Emu eggs are larger. The female does not care for the eggs or the chicks but moves on to lay eggs in the nests of several other males. The male incubates the eggs for 50–52 days, removing or adding litter to regulate the temperature, then protects the brown-striped chicks who stay in the nest for about nine months, defending them fiercely against all potential predators, including humans. The young males then go off to find a territory of their own.

"Young cassowaries are brown and have buffy stripes. They are often kept as pets in native villages [in New Guinea], where they are permitted to roam like barnyard fowl. Often they are kept until they become nearly grown and someone gets hurt. Mature cassowaries are placed beside native houses in cribs hardly larger than the birds themselves. Garbage and other vegetable food is fed them, and they live for years in such enclosures; for in some areas their plumage is still as valuable as shell money. Caged birds are regularly bereft of their fresh plumes."

Diet

Cassowaries are predominantly frugivorous, but they will take flowers, fungi, snails, insects, frogs, birds, fish, rats, mice, and carrion. Fruit from at least twenty-six plant families have been documented in the diet of cassowaries. Fruits from the laurel, podocarp, palm, wild grape, nightshade, and myrtle families are important items in the diet. The cassowary plum takes its name from the bird.

Where trees are dropping fruit, cassowaries will come in and feed, with each bird defending a tree from others for a few days. They move on when the fruit is depleted. Fruit is swallowed whole, even items as large as bananas and apples.

Cassowaries are a keystone species of rain forests because they eat fallen fruit whole and distribute seeds across the jungle floor via excrement.

As for eating the Cassowary, it is supposed to be quite tough. Australian administrative officers stationed in New Guinea were advised that it "should be cooked with a stone in the pot: when the stone is ready to eat so is the Cassowary".

Distribution and habitat

Cassowaries are native to the humid rainforests of New Guinea and nearby smaller islands, and northeastern Australia. They will, however, venture out into palm scrub, grassland, savanna, and swamp forest. It is unclear if some islands' populations are natural or the result of trade in young birds by natives.

Threats

Road sign -Cairns, Queensland, Australia-26Oct2007
A road sign in Cairns, Queensland, Australia

The Southern Cassowary is endangered in Queensland, Australia. Kofron and Chapman (2006) assessed the decline of this species. They found that, of the former cassowary habitat, only 20 - 25% remains. They stated that habitat loss and fragmentation is the primary cause of decline. They then studied 140 cases of cassowary mortality and found that motor vehicle strikes accounted for 55% of them, and dog attacks produced another 18%. Remaining causes of death included hunting (5 cases), entanglement in wire (1 case), the removal of cassowaries that attacked humans (4 cases), and natural causes (18 cases), including tuberculosis (4 cases). 14 cases were for unknown reasons.

Hand feeding of cassowaries poses a big threat to their survival, because it lures them into suburban areas. There, the birds are more susceptible to vehicles and dogs. Contact with humans encourages cassowaries to take food from picnic tables.

Feral pigs are a huge problem. They destroy nests and eggs but their worst effect is as competitors for food, which could be catastrophic for the cassowaries during lean times.

In February 2011 Cyclone Yasi destroyed a large area of cassowary habitat, endangering 200 of the birds, around 10% of the total Australian population.

Species of cassowary

There are three living species of cassowary:

  • Southern cassowary, Casuarius casuarius, which lives in Australia and New Guinea
  • Northern cassowary, Casuarius unappendiculatus, which lives in New Guinea and New Britain. This is also called the Single-wattled cassowary, Gold(en)-neck(ed) cassowary or Blyth's cassowary.
  • Dwarf cassowary, Casuarius bennetti, which lives in New Guinea. It weighs up to 25 kg (55 lb) and can grow to 1 m (3 ft) tall. It is also called Bennett's cassowary, Mountain cassowary or Mooruk.

Description

The southern cassowary is the largest forest bird in the world, and the second heaviest bird in the world after the ostrich. It is third tallest after the ostrich and emu. Females are bigger and more brightly coloured. Adult Southern Cassowaries are between 1.5 m (5 ft) to 1.8 m (6 ft) tall. Some females may get as big as 2 m (7 ft), and weigh about 70 kg (154 lb). They do not have feathers on their necks. The necks are brightly colored in red, blue, purple and yellow. The southern cassowary has two wattles, loose skin, which hangs down from their neck. The Northern Cassowary has one wattle. The Dwarf Cassowary has no wattles.

Cassowaries have three toes on each foot. Each has a sharp claw. The middle toe has a claw like a dagger, which is 120 mm (5 in) long. Because a cassowary can kick, this claw is very dangerous and can hurt or kill enemies. Scientists believe they can run up to 50 km/h (31 mph). They can jump up to 1.5 m (5 ft) and they can swim. There have been reported attacks on people and animals by cassowaries. In April 1926, a cassowary killed a 16-year-old boy near Mossman, Queensland.

The cassowary's wings are small, and are not flight feathers. They are not adapted for flying.

Breeding

Casuarius casuarius, egg
A cassowary egg.
Casuarius casuarius -Emmagen Creek, Queensland, Australia -chick-8
Cassowary chick

Females lay between three and eight large, pale green-blue eggs at a time. These large eggs are about 90 mm (4 in) by 140 mm (6 in) and weigh about 600 grams. Ostrich and emu eggs are bigger. The male sits on the eggs for two months until they hatch. He then looks after the brown-striped chicks for nine months. The female mates with two or three males each year. A cassowary at the Healesville Sanctuary lived for 61 years.

The casque

All three types of cassowary have a horn-like helmet called a casque on the top of their head. The casque is a keratinous skin (like a finger nail) over an inside made of firm, but foam like material. This material can be bent and squeezed but it goes back to its proper shape. The name cassowary comes from two Papuan words meaning "horned head". The reason for the casque is unknown. There are a number of different ideas, such as:

  • It may have a sexual purpose as the females casque is larger
  • It might be used to push through the thick forest,
  • It might be a weapon for fighting other cassowaries
  • It might be a tool for pushing leaf litter out of the way when looking for food
  • It might keep the cassowary's skull safe if they crash into trees.

Biologist Andrew Mack has watched cassowaries and disagreed with many of these ideas. He thinks that the casques play a part in the way cassowaries hear sounds or the way that they make sounds. He discovered that the dwarf Cassowary and southern cassowary make a very low sound. It is the lowest known bird call, like a "boom", which people can only just hear. The southern cassowary sound was measured at 32 hertz, and the Dwarf Cassowary was even lower at only 23 hertz. The birds live by themselves, they do not live in groups so the "booming sound" might be a way for the birds to communicate (talk) over a long distance in thick rainforest. Scientists think that this way of talking may be how dinosaurs communicated with each other.

Diet

Kasuar fg1
Cassowary scat (feces) showing all the seeds

Their main food is fruit, but they eat other things such as snails, fungi, ferns and flowers. They are important because they spread plant and fruit seeds through the forest. Each cassowary is known to live in an area of up to 700 ha (1,730 acres), so they carry seeds a long way. At least 70 rainforest trees need the cassowary to spread their seeds. Their seeds are too big for other rainforest animals to carry. Seeds from 21 plants have to be eaten and pass through the cassowary or they will not grow. Some seeds are poisonous to all other animals; only the cassowary can eat them. Scientists have worked out that about 150 rainforest plants need the cassowary.

Endangered species

The southern cassowary is now listed as endangered in Australia. Scientists think there are only between 1200 and 1500 cassowaries left in Australia. Many of the forest places that they like to live in have been cleared for farming and other development. It has been worked out that 75% of rain forest, where cassowaries used to live, have been cleared in Australia. When Cyclone Larry hit the Mission Beach area in 2006 a lot of cassowary forest was flattened. It is thought that 18% of the birds were killed by the storm. Animals such as wild pigs, dogs and cats, have become a big threat to the birds. Motor cars are a big danger to the birds. Scientists say that 70% of known cassowary deaths at Mission Beach, Queensland, were birds killed trying to cross roads.

The northern cassowary in New Guinea is listed as vulnerable. They could easily become an endangered animal unless things are done to protect them. Scientists do not know how many birds there are, but they think there may be anywhere from 2,500 to 9,999 northern cassowaries left.

Saving the cassowary

Cassowary road sign
Road sign to protect cassowaries.

The CSIRO are studying cassowary faeces to see if they can use their DNA to count how many birds are left. In 2008, the Australian Government stopped rainforest land being used to build houses at Mission Beach. They are going to try and keep corridors (narrow forest areas) so the birds can move between rainforest areas safely. People will be asked to replant forest trees and plants on their land to help make these corridors. The government is looking at buying land for more corridors. Scientists are finding out when and where cassowaries cross roads. This will mean strict limits on motor car speeds to protect cassowaries that might try to cross some roads. Plans are being looked at to build raised roads so the birds can pass underneath.

Many zoos, such as the Australian Reptile Park in Gosford, the Airlie Beach Wildlife Park and the Denver Zoo are trying to breed cassowaries. Cassowaries in zoos have lived for up to 60 years. The first cassowary kept in a zoo was in Amsterdam in 1597. It had been brought back as a present for the Holy Roman Emperor Rudolf II.

Cassowaries in art and music

In 2007, Australian singer Christine Anu, made an album called Chrissy's Island Family. This is a collection of songs for children. One of the songs is called Cassowary. It is about Samu, the Wakka Woo cassowary. There is picture book for children, called Sisi and the Cassowary, by Arone Raymond Meeks. It has drawings in traditional aboriginal style to tell a Dreamtime like story.

English natural history writer and artist, John Gould, had drawings of the cassowary in his set of seven books called The Birds of Australia. These were printed in London between 1851 and 1869. The cassowary drawings were completed by Henry Richter. Richter's watercolor painting of the cassowary is in the museum in Melbourne, Victoria.

Other large birds

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