CASUARIIFORM

(order Casuariiformes), any of a group of large, flightless birds that includes the cassowary (Casuarius) and the emu (Dromaius novaehollandiae) as well as several extinct birds known only by fossil evidence. The emu was not seen by Europeans until 1788, more than a century after the first cassowaries had been seen by Europeans. At that time there were four living species of emu, but the Kangaroo Island, King Island, and Tasmanian emus were exterminated shortly after colonization of their respective islands. The emu, a native of Australia, is the world's second largest bird; only the ostrich (Struthio camelus) is larger. Very large emus can reach 55 kg (120 pounds), although the average weight for males is 35 kg and for the females 40 kg. They may stand up to 1.8 m (6 feet) in height. The three species of cassowary, found only in northern Australia, New Guinea, and adjacent islands, are the Australian, or double-wattled, cassowary (C. casuarius; see ), the single-wattled cassowary (C. unappendiculatus), and the dwarf cassowary (C. bennetti). All the casuariiforms are running (cursorial) birds and show various adaptations to this life-style. As in many cursorial birds, the hind toe has disappeared and the birds move on three sturdy front toes. On the inner toe of the cassowary the claw has evolved into a long, spurlike structure, quite effective when the cassowary defends itself by kicking. Emus and cassowaries are good swimmers as well as fast runners. The plumage of the casuariiforms has a hairlike look different from that of most birds, because the feathers lack the barbules that interlock to create the wide flat surface of most bird feathers. These feathers are less likely to become damaged or tangled in the dense, thorny underbrush that most casuariiforms inhabit. There is no differentiated tail. The plumage of the emus is brown, while that of the cassowaries is black. In addition, the cassowaries have a flattened horny helmet or casque on the head; this is believed to protect the bird from injury while running through dense forests. The casque may reach 15 cm (6 inches) in C. casuarius. Bright red or orange fleshy wattles on the head and neck are characteristic of C. casuarius and C. unappendiculatus. Cassowaries are solely rain forest inhabitants while emus are found in a wide variety of habitats, in arid scrub country and open plains as well as in forested areas. Members of this order eat mostly vegetation, including leaves, fruits, and seeds, but emus are known to feed on insects such as grasshoppers when these are abundant. Cassowary clutches range from 3 to 8 eggs; those of the emu are larger, averaging 9 and sometimes reaching 16 eggs. The greenish eggs are about 13 cm long and weigh between 450 and 800 g (16 and 28 ounces). The incubation period lasts 58 to 61 days for the emus and 49 to 52 days for the cassowaries. Unlike most bird species, only the male incubates the egg in the casuariiforms. When the chicks hatch they are patterned with alternating dark and light longitudinal stripes. They mature in about two years. Cassowaries live year-round in pairs or family parties. During the nonbreeding season emus may gather in large flocks and sometimes travel long distances. These birds have long been important as food to the native peoples of the Australasian region. Cassowary chicks are frequently captured and raised in a pen until they are large enough to eat. The plumage of these birds is used for personal decoration, particularly the feathers of the emu. The emu is much less common than formerly throughout much of its range, but in western Australia it is still abundant. It is an agricultural pest around wheat farms, where it breaks fences and crushes and eats the crop. Western Australia pays a bounty on emus, and between 5,000 and 40,000 of the birds are taken each year. Emu (Dromaius novaehollandiae) (order Casuariiformes), any of a group of large, flightless birds that includes two families: Dromaiidae for the emu (Dromaius novaehollandiae; see photograph), found only in Australia; and Casuariidae for three species of cassowaries (Casuarius), restricted to northern Australia, New Guinea, and nearby islands. Of the two groups, the emu is far better known, both biologically and popularly, being exhibited in zoos around the world. Several extinct casuariiform birds are known only by fossil evidence. The emu was first identified by European explorers in 1788, more than a century after the first cassowaries had been seen by Europeans; in 1697 a Dutch navigator, Willem de Vlamingh, had seen the emu's footprints in western Australia and had attributed them to a Kasuarius. Cassowaries first became known to Europeans in the 17th centurythere was a published reference to a Casoaris in 1658when the Portuguese and Dutch colonized the East Indies. Both names, emu and cassowary, were originally applied to cassowaries; the emu was known as the New Holland or New South Wales cassowary until the early 19th century, when the name emu was gradually transferred to it. By the late 19th century about 11 species of cassowaries were recognized, but greater understanding of variation within species has reduced the number to three: the double-wattled, or Australian, cassowary (Casuarius casuarius), the single-wattled, or one-wattled, cassowary (C. unappendiculatus), and the dwarf, or Bennett's, cassowary (C. bennetti). Additional reading D. Fleay, Nesting of the Emu, Emu, 35: 202210 (1936), presents observations of this species in captivity. D.W. Gaukroger, The Emu at Home, Emu, 25:5357 (1925), describes nesting habits in the wild. Austin L. Rand and E. Thomas Gilliard, Handbook of New Guinea Birds (1967), contains a summary of the biology and classification of cassowaries; and D.L. Serventy and H.M. Whittell, Birds of Western Australia, 5th ed. (1976), includes a summary of emu habits and statistics of kills. H.L. White, Notes on the Cassowary (Casuarius australis Wall), Emu, 12:172178 (1913), presents field observations on habits and nesting in Queensland, with illustrations. D.L. Serventy The Editors of the Encyclopdia Britannica