Casuarius casuarius

Geographic Range

Southern cassowaries are found in New Guinea, Cape York, Ceram and Aru Islands.

• Biogeographic Regions
• australian australian
  • introduced introduced
  • native native
• oceanic islands oceanic islands
  • introduced introduced
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Southern cassowaries live primarily in lowland rainforests, typically less than 1,100 meters elevation, and occasionally are found in eucalyptus forests, savannas, palm scrub, and in forested swamps.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• rainforest rainforest
• scrub forest scrub forest

Physical Description

Southern cassowaries are large, robust birds with long powerful legs for running and defense; the claws on the toes are up to 12 cm long. Their bodies are covered with dark brown or black feathers which look more like thick, coarse hair. The neck and head have no feathers and are boldly colored blue and red. On their heads there is a large bony casque which is made of trabecular bone and cartilage. The wings are extremely small and there are vestiges of primary feathers in the form of five or six long white spines. Cassowary chicks are brown with black stripes running the length of their bodies for their first three to six months. Juveniles are brown instead of black and have smaller casques. They do not get the vividly colored necks until they are about one year old. Females are 127 to 170 cm long and up to 59 kg, are larger than the males which are 29 to 34 kg. Southern cassowaries are the largest of the three species of cassowary and the only species to have have two bright red flaps of skin, called wattles, hanging from their neck.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Females are polyandrous; a female will usually breed with two to three males throughout the mating season, starting a new nest every time, which the male will incubate. Courtship consists of the males making a “boo-boo-boo” call while inflating his throat.

• Mating System
• polyandrous polyandrous

The breeding season is in winter, when fruit is most abundant. The nest is a pad of vegetation on the ground and there are typically about 4 bright green eggs in a clutch. Incubation, which is exclusively done by the males, lasts for 47 to 61 days. Once the chicks hatch they stay with their father until they become independent at about nine months. At about three years of age, southern cassowaries are able to reproduce.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

After the eggs are laid all care of the eggs and offspring are done by males. Males construct a mat of vegetation which will become the nest where they incubate the eggs for 47 to 61 days. The chicks are precocial at hatching, but dependent on their male parents for protection from predators and for teaching them how to find food for themselves. This period will last for about 9 months, when the males will abandon the juvenile cassowaries.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • male
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
  • protecting
    • male
• pre-independence
  • provisioning
    • male
  • protecting
    • male

Lifespan/Longevity

There is little known about the lifespan of southern cassowaries in the wild, but in captivity southern cassowaries have lived 20 to 40 years.

Behavior

Southern cassowaries have very small wings and are unable to fly. Instead they rely on their powerful legs for mobility and defense. They can be almost silent while moving slowly through the forest. When alarmed, they are capable of crashing through the forest at almost 50 kilometers per hour, using the bony casques on the top of their head to push vegetation out of their way. Southern cassowaries are very good swimmers and are also good jumpers. Southern cassowaries are solitary and shy, but they can be aggressive and will occasionally attack humans using their powerful legs to lash out with their large claws.

• Key Behaviors
• cursorial
• terricolous
• diurnal diurnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

As solitary animals, southern cassowaries have their own home range which they will defend against other cassowaries. In the forest they will produce very deep, loud territorial roar which can be heard by cassowaries a significant distance away. It is unknown how large an area of forest a single southern cassowary requires although the type and number of trees cassowaries are dependent on for food would suggest that each cassowary requires an area that is fairly large.

Communication and Perception

Southern cassowaries communicate with each other by issuing very loud deep roars which travel well through the forest. These roars are up to 40 decibels louder than the surrounding forest noise, and are at frequencies which are at the very bottom end of what humans can perceive, about 23 Hertz. Cassowaries are one of the only birds to have been recorded making vocalizations this low. There is some speculation about whether the casques on their heads are somehow related to these impressive sounds. It is speculated that the casque could play a role in receiving or producing these sounds. These calls are territorial, warning other cassowaries of their presence.

• Communication Channels
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Southern cassowaries are frugivorous, feeding mostly on fruits from canopy species in the forests where they live. Because these birds cannot fly they must rely on finding fruit that has fallen to the ground. They also eat insects, small vertebrates, and fungi. Inspection of the feces reveals that commonly ingested fruits are Davidsonia pruriens , Acemena divaricata and members of the laurel family ( Lauraceae ).

• Primary Diet
• herbivore herbivore
  • frugivore frugivore

• Animal Foods
• mammals
• amphibians
• reptiles
• insects
• terrestrial non-insect arthropods

• Plant Foods
• fruit

• Other Foods
• fungus

Predation

It is unknown whether cassowaries have any natural predators, but humans could be considered a predator because cassowaries are sometimes eaten by humans.

Ecosystem Roles

Cassowaries live primarily on fruit from a large number of species of trees. When cassowaries eat the fruit the seeds pass through their system and are dispersed far from where they originally fell. The seeds are often still viable after passing through the digestive system of cassowaries. In a typical pile of cassowary dung there can be as much as one kilogram of seeds. In a study of the effects of seed dispersal by cassowaries, the seeds from 78 species of plants were found and 70 of these species' seeds were able to germinate after being passed through the cassowaries. Some of the species found in cassowaries dung include Davidsonia pruriens , Acemena divaricata , Polyalthia michaelii , Acronychia acronychioides and a large number from the Lauraceae family.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Southern cassowaries are important in the mythology of the indigenous peoples of New Guinea and Australia. These birds are captured as chicks and raised in villages so that their feathers can plucked and used in headdresses and the quills can be used as nose ornaments. Eventually, when the birds reach a certain size they are killed for food. There has been a trade of cassowaries in Southeast Asia for over 500 years. It is possible that populations of southern cassowaries on Australia and some of the islands surrounding New Guinea are the result of human introductions through trade.

• Positive Impacts
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

Although they are usually shy, southern cassowaries can be aggressive towards people, especially when kept in captivity. Southern cassowaries will charge people, jumping at them while slashing with their 12 cm claws. They can cause serious injury and sometimes death. In 2004 southern cassowaries were voted by the Guinness Book of World Records as the worlds most dangerous bird for these reasons.

• Negative Impacts
• injures humans

Conservation Status

The biggest threat to southern cassowaries is the destruction of their habitat. These birds are also sometimes killed by cars and their populations are disrupted by feral pigs and dogs. There has been a 30% decline in their numbers in the last 30 years. Fortunately, in Australia, the destruction of habitat has almost completely stopped and in New Guinea there are large areas where the bird is not hunted which helps their numbers. Southern cassowaries will be safe as long as there are large areas of undisturbed forests.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Dan Hulbert (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Barrett, N. 1991. Flightless Birds . New York: Franklin Watts.

Cohen, J. 2006. "Fact sheets double-wattled cassowary" (On-line). Smithsonian National Zoological Park. Accessed September 12, 2006 at http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-cassowary.cfm .

Folkard, C. 2004. Guinness Book of World Records, 2004 . New York: Turtleback Books.

Mack, A., J. Jones. 2003. Low-frequendy vocalizations by cassowaries. The Auk , 120: 1062-1068.

Stocker, G., A. Irvine. 1983. Seed dispersal by cassowaries (Casuarius casuarius) in northern Queensland's rainforests. Biotropica , 15: 170-176. Accessed November 09, 2006 at http://0-www.jstor.org.ariadne.kzoo.edu/cgi-bin/jstor/printpage/00063606/di995240/99p01186/0.pdf?backcontext=page&dowhat=Acrobat&config=jstor&userID=92718064@kzoo.edu/01cce44060d0810ecf4aa8c5&0.pdf .

2003. Cassowaries. Pp. 75-81 in Grizmek's Animal Life Encyclopedia , Vol. 8, Second Edition. New York: Thomson Gale.

1985. Ostriches and their Relatives - The Ratites. Pp. 19-27 in The Encyclopedia of Birds , Vol. 1, First Edition. New York: Facts on File.