Adult double-wattled cassowary at the National Zoo. (71K)

(Jessie Cohen/NZP Graphics)

Margie Gibson - NZP Staff Writer

ZOOGOER - January-February 1993

"They kill more people each year than polar bears do." "One swift kick can rip open your abdomen." Comments about tigers, or sharks, perhaps? No, the subject is a bird. A BIG bird, a double-wattled cassowary to be exact.

The National Zoo is home to two of these unusual creatures, which live in separate enclosures in one of the park's most peaceful areas: behind the Bird House, along the walk, just past the ostriches and flamingos. The pair of double-wattled cassowaries (Casuarius casuarius bicarunculatus) are young--both were born in July 1991. The female, from the Denver Zoo, arrived here in December 1991, and the male, from a breeding farm in California, joined her this past September. (His airfare was courtesy of the Theodore H. Reed Animal Fund, supported by ZooFari proceeds.)

Cassowaries are ratites, a group of flightless birds that includes the extinct moas of New Zealand and elephant birds of Madagascar, as well as the living South American rheas, African ostriches, New Zealand kiwis, and Australian emus. The three species of cassowaries are closely related to emus, but scientists are not sure how or even whether these species are related to other flightless birds.

Because the claws, long skinny necks, huge eyes, prominent beaks, and muscular scale-covered legs of ratites look primitive, scientists once speculated that they are among the most ancient of birds, perhaps the direct descendants of dinosaurs and the precursors to flying birds. Unfortunately, the fossil record is sparse as the delicate bones and feathers of birds do not fossilize well. The oldest cassowary fossil dates only from the late Pleistocene (10,000 to 50,000 years ago), and the few ratite specimens that have been found shed little light on their evolutionary history.

An examination of the skeletal structure of modern ratites indicates, however, that ratites are not the evolutionary link between dinosaurs and birds. In fact, ratite ancestors flew. Their wing structure is very similar to that found in other birds and it appears that they lost their ability to fly as their body size increased. This in turn led to changes in bones, muscles, and plumage. Their wing muscles are weak and unable to support flight because the breastbone lacks a place for the attachment of wing muscles. To compensate for flightlessness and to defend themselves against potential predators, ratites have strong, powerful legs. They can run fast-cassowaries, for example, reach speeds of 30 miles per hour. And cassowaries, as well as ostriches, pack powerful, even lethal, kicks.

Cassowaries have been exhibited in the West since 1597, when the first living cassowary arrived at an Amsterdam menagerie. Their common and scientific names come from the Malay word for the bird, "kesuari." Thomas Wall, a British explorer and naturalist who joined an expedition to Australia, was one of the first Europeans to see cassowaries in the wild. He published the first scientific description of the birds in 1854, although he lost his specimen-it was left in a bag on the shore of an Australian bay.

Cassowaries have been exhibited at the National Zoo almost since its inception. A cassowary arrived in 1893, one of many animals that Samuel Langley, Secretary of the Smithsonian, acquired from the Adam Forepaugh Circus.

The double-wattled cassowary lives in the low swamps and rainforests of northern Australia and New Guinea. Two other species are found in New Guinea, and live in both lowland and mountain forests. Watermelon-sized shortly after hatching, cassowaries reach five feet in height and weigh up to 130 pounds when they are fully grown. They swim well and in the wild are often found near riverbanks.

The Zoo's young birds are covered with fluffy, narrow, dark-brown feathers that have a hairlike appearance. The feathers, like those of other ratites, look fluffy because the parts of the feather called barbs, which jut off the shaft, are not hooked together with the tiny barbules that link the individual barbs in flying birds. Anyone who has smoothed the ruffled feathers of a nonratite knows how the individual strands of the feather cling together. In contrast, ratites' feathers, which do not need to be stiff to push against the air in flight, allow the air to flow through.

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Immature cassowary. (Jessie Cohen/NZP Graphics)

The rather dull coloration of the Zoo's cassowaries will give way to vibrant hues as they mature. Already, a greenish-blue color tints the skin around their eyes. The dark brown feathers will become shiny black. Their necks are sparsely covered with down now, but, by the time they are three years old, this will be transformed to extravagantly colored deep blue and scarlet skin. The wattle (a flap of loose skin extending like a bib from the bird's neck) will turn blue at the base, graduating into a deep pink farther down.

The bumps on the top of their heads are the beginning of the casque, a hard, helmetlike structure made of keratin that crowns the cassowary. One of the reasons the cassowaries were thought to be related to dinosaurs is that although very few vertebrates have casques, many dinosaurs did. The double-wattled cassowary's tall and bladelike casque is not merely decorative-the bird lowers its head and pushes through dense forest, using the casque to clear a path through the tangles. Cassowaries in zoos have also been seen using the casque to dig up buried food items.

In the rainforest, these birds eat fruit that has fallen to the forest floor, supplemented by insects, fungus, roots, and small vertebrates. Zoodwelling cassowaries are fed bird pellets, along with apples, oranges, and bananas. As they get older, a bit of meat will be added to their daily diet.

The cassowary's extremely powerful kick is all the more dangerous because the bird's toes are tipped with sharp, daggerlike claws. The claws are lethal weapons and are even used by tribal people in New Guinea as spear points. Nonetheless, cassowaries are shy, solitary birds that, despite their size, are rarely glimpsed in the wild.

In the wild, male and female come together only briefly during the August and September breeding season. Zoo breeding programs are delicate affairs: male and female must be carefully put together each day, and if the timing isn't perfect, serious fights may occur. The male makes purring sounds to interest his mate, but if the female isn't ready, she will fight him off. Unusual among birds, females are slightly larger than males, although the sexes otherwise look alike.

The female lays a clutch of four to ten eggs in a depression in the ground covered with dry leaves and well concealed in the vegetation of the densest part of the forest. Then she disappears from the scene and the male takes charge. He incubates the five-and-a-quarter by three-and-a-half-inch eggs for about 35 days, then takes care of the young chicks for about a year before resuming his solitary ways.

Although not endangered, cassowary populations were greatly reduced in the late 1800s, when sugar planters destroyed many of the birds and used their skins for hearth rugs and doormats. New Guinea natives hunt them for meat and keep them in cages so they can use the feathers in clothing. Young cassowaries even walk village streets and are allowed to play with children, although as the birds mature they are banished to pens or released into the forest. According to Charles Pickett, the Zoo's associate curator of birds, cassowaries even serve as currency. In the early 1980s, about 20 cassowaries were considered a fair price for a wife in parts of New Guinea.