Casuarius casuariussouthern cassowary

Ge­o­graphic Range

South­ern cas­sowaries are found in New Guinea, Cape York, Ceram and Aru Is­lands. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985)

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Bar­rett, 1991)

  • Range elevation
    0 to 1,100 m
    0.00 to ft

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Bar­rett, 1991)

  • Sexual Dimorphism
  • female larger
  • Range mass
    29 to 59 kg
    63.88 to 129.96 lb
  • Range length
    102 to 170 cm
    40.16 to 66.93 in

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985)

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Cohen, 2006)

  • Breeding interval
    Females will mate with 2 to 3 males during the mating season.
  • Breeding season
    Breeding occurs during the austral winter, from June to July.
  • Range eggs per season
    4 to 8
  • Range time to hatching
    47 to 61 days
  • Average time to independence
    9 months
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (male)
    3 years

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Cohen, 2006)

  • Parental Investment
  • 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. (Cohen, 2006; Stocker and Irvine, 1983)

  • Range lifespan
    Status: captivity
    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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Cohen, 2006)

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Cohen, 2006; Mack and Jones, 2003)

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Mack and Jones, 2003)

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). ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985; Cohen, 2006; Stocker and Irvine, 1983)

  • 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. ("Cas­sowaries", 2003)

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. (Stocker and Irvine, 1983)

  • Ecosystem Impact
  • disperses seeds
Mu­tu­al­ist Species
  • lau­rels (Lau­raceae)
  • mul­ber­ries (Moraceae)
  • palms (Are­caceae)
  • myr­tles (Myr­taceae)

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. ("Cas­sowaries", 2003; "Os­triches and their Rel­a­tives - The Ratites", 1985)

  • Positive Impacts
  • 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. ("Cas­sowaries", 2003; Folkard, 2004)

  • 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. ("Cas­sowaries", 2003)

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

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

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

Ref­er­ences

2003. Cas­sowaries. Pp. 75-81 in J Jack­son, W Bock, D Olen­dorf, eds. Grizmek's An­i­mal Life En­cy­clo­pe­dia, Vol. 8, Sec­ond Edi­tion. New York: Thom­son Gale.

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

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.