Cassowary
From Wikipedia, the free encyclopedia
| Cassowaries | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Image:Kasuaris.jpg Southern Cassowary
Image:CassowarySkullLyd4.png | ||||||||||||
| Scientific classification | ||||||||||||
| ||||||||||||
| Species | ||||||||||||
|
Casuarius casuarius |
Cassowaries (genus Casuarius) are very large flightless birds native to the tropical forests of New Guinea and northeastern Australia. Some nearby islands also have small cassowary populations, but it is not known if these are natural or the result of the New Guinea trade in young birds. They are frugivorous; fallen fruit and fruit on low branches is the mainstay of their diet. They also eat fungi, snails, insects, frogs, snakes and other small animals. They are a keystone species of rain forests because they eat fallen fruit whole and distribute seeds across the jungle floor via excrement.
Contents |
[edit] Taxonomy and evolution
Cassowaries (from the Indonesian name kasuari) are part of the ratite group, which also includes the emu, rhea, ostrich, moa (now extinct), and kiwi. There are three species recognized today:
- Southern Cassowary or Double-wattled cassowary C. casuarius of Australia and New Guinea.
- Dwarf Cassowary C. bennetti of New Guinea and New Britain.
- Northern Cassowary C. unappendiculatus of New Guinea.
The evolutionary history of cassowaries, as of all ratites, is not well known. A fossil species was reported from Australia, but for reasons of biogeography this assignment is not certain and it might belong to the prehistoric "emuwaries", Emuarius, which were cassowary-like primitive emus.
Cassowaries are aggressive birds that nest on the ground. The Cassowary is the third largest flightless bird.They use their long legs to pluck apples off of trees.
[edit] Description
The Northern and Dwarf Cassowaries are not well known. All cassowaries are usually shy, secretive 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.
The Southern Cassowary is the largest land creature in Australia and the second heaviest extant bird in the world after the ostrich. It is third tallest after the ostrich and emu.[1]
Females are bigger and more brightly coloured. Adult Southern Cassowaries are 1.5 to 1.8 m (5 to 6 feet) tall, although some females may reach 2 m (6 feet 8 inches), and weigh about 70 kilograms (154 pounds). [1]
A cassowary's three-toed feet have sharp claws; the dagger-like middle claw is 120 mm (5 inches) long. This claw is particularly dangerous since the Cassowary can use it to kill an enemy, disembowelling it with a single kick. They can run up to 50 km/h (32 mph) through the dense forest. They can jump up to 1.5 m (5 feet) and they are good swimmers.[citation needed]
All three species have a horn-like crests called casques on their heads. These consist of "a keratinous skin over a core of firm, cellular foam-like material".[2] 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 on the basis of personal observation.[3] 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 careering into small trees. The casque would help protect the skull from such collisions."[2] Mack and Jones give a further speculation: 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.[3] This "boom" is the lowest known bird call, and is on the edge of human hearing.[5]
Females lay three to eight large, pale green-blue eggs in each clutch. These eggs measure about 9 by 14 cm (3½ by 5½ inches) — only ostrich and emu eggs are larger. The female does not care for the eggs or the chicks; the male incubates the eggs for two months, then cares for the brown-striped chicks for nine months, defending them fiercely against all potential predators, including humans.[citation needed]
[edit] Conservation status
Southern and Northern Cassowaries are threatened species because of habitat loss; estimates of their current population range from 1,500 to 10,000 individuals. About 40 are kept in captivity in Australia. Habitat loss has caused some cassowaries to venture out of the rainforest into human communities. This has caused conflict particularly with fruit growers. However, in some locations such as Mission Beach, Queensland, tourism involving the birds has been launched.
The Southern Cassowary is listed as endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.
[edit] Threats
| This article or section may contain original research or unverified claims. Please improve the article by adding references. See the talk page for details. (December 2007) |
Loss of habitat owing to the destruction of rainforest over the last 100 years has been the major factor in the decline of the Cassowary. For the last 20 years Mission Beach has experienced the greatest amount of lowland rainforest clearing in Australia. In the Mission Beach area alone, Cassowaries have lost about 50% of their critical habitat in the past ten years. The survival of many rainforest trees is tied to the Cassowary's survival.
Traffic is another big problem. Between 1st July and 30th September 2003 one Sub Adult bird was killed by a car in the Mission Beach area despite reduced speed limits, big warning signs and recent road improvements intended to make the roads safer for Cassowaries.
Hand feeding of Cassowaries poses a big threat to their survival. In suburban areas the birds are more susceptible to vehicles and dogs. Contact with humans encourages Cassowaries to take most unsuitable food from picnic tables.
Feral pigs are a huge problem. They probably destroy nests and eggs; but their worst effect is as competitors for food, which could be catastrophic for the Cassowaries during lean times. Pigs also contaminate water sources.
Dogs chase the birds away from potential food sources in suburban areas.
[edit] Interactions with humans
The 2004 edition of the Guinness World Records lists the cassowary as the world's most dangerous bird. Normally cassowaries are very shy but when disturbed can lash out dangerously with their powerful legs. During World War II American and Australian troops stationed in New Guinea were warned to steer clear of the birds. They are capable of inflicting fatal injuries to an adult human. Usually, attacks are the result of provocation. Wounded or cornered birds are particularly dangerous. Cassowaries, deftly using their surroundings to conceal their movements, have been known to out-flank organized groups of human predators. Cassowaries are considered to be one of the most dangerous animals to keep in zoos, based on the frequency and severity of injuries incurred by zookeepers.
[edit] Role in seed dispersal and germination
[edit] See also
[edit] References
- ^ a b [1]
- ^ a b Crome, F., and L. Moore. 1988. The cassowary’s casque. Emu 88:123–124.[2]
- ^ a b *Mack AL, Jones J. 2003. Low-frequency vocalizations by cassowaries (Casuarius spp.). The Auk 120(4):1062–1068 [3]
- ^ Webber, B.L. and Woodrow, I.E. Cassowary frugivory, seed defleshing and fruit fly infestation influence the transition from seed to seedling in the rare Australian rainforest tree, Ryparosa sp. nov. 1 (Achariaceae). Functional Plant Biology 31: 505-516. [4]
- Stay in Touch, Philip Clark (ed), The Sydney Morning Herald, 5 November 1990. Cites "authorities" for the death claim.
- Underhill D (1993) Australia's Dangerous Creatures, Reader's Digest, Sydney, New South Wales, ISBN 0-86438-018-6
- Readers' Digest, June 2006 issue.
[edit] External links
- C4 - Cassowary Conservation based in Mission Beach
- [6] The cassowary
- The Cassowary Bird
- ARKive - images and movies of the southern cassowary (Casuarius casuarius)
- Cassowary videos on the Internet Bird Collection
bg:Казуар ca:Casuari da:Kasuarer de:Kasuare es:Casuarius eo:Kazuaro id:Casuarius it:Casuarius he:קזוארים no:Kasuarer pt:Casuar ru:Казуары sl:Kazuar fi:Kasuaarit sv:Kasuarer zh:鶴鴕 ja:ヒクイドリ
Categories: All articles with unsourced statements | Articles with unsourced statements since February 2007 | Articles that may contain original research since December 2007 | Casuarius | Birds of Australia | Flightless birds | Heraldic birds | Higher-level bird taxa restricted to the Australasia-Pacific region | Genera of birds
