Ostriches belong to a striking group of flightless
birds known as ratites, that also includes
emus, cassowaries, rheas, and kiwis. Ratites have
flat, smooth breastbones that lack a keel to which
flight muscles could attach. They are thus unable
to fly, and have weak wing muscles. They do use
their wings, spreading them out to help them cool
off, and also to splash water when bathing. Ratite
feathers are different from those of flying birds.
The individual strands are not interlocked, and
thus they are soft and billowy and air passes right
through them. Their plumes have long been admired
by humans and used for decoration and
adornment. As with other birds, their feathers
function as protection from the elements, and
ratites preen, spreading waterproofing oil to their
feathers with their beaks. They also molt once a
year. Ratites have heavy, strong bones and powerful
leg muscles, and are able to run swiftly. They
are omnivores, feeding on a variety of grasses,
plants, seeds, fruit, insects, and small animals.
There are many farms in the United States that
raise ostriches, emus, and rheas for their feathers,
hide, meat, and oil. In their native countries,
ratites are hunted or raised for their feathers and
as food. Ostriches have also been tamed for riding
and for pulling carts.
Ostriches have long necks and legs and are the largest living birds. Males stand eight feet tall, and weigh three hundred pounds. The ostrich can take strides of twenty-five feet and outrun pursuers at speeds of forty miles per hour. If cornered, the ostrich has a powerful kick that can maim an enemy. It has two toes on each foot, and a razor-sharp toenail that both grips the ground while running and can slash the flesh of its enemy. Male ostriches are black with white plumes on their tail and wings. Females are grayish-brown. The head and legs are featherless. The neck is covered with down and is red or grayish. The ostrich has huge eyes with long protective lashes and has keen eyesight for spotting danger a long way off. It can make loud hissing and roaring noises. Ostriches are native to Africa; they are nomadic and graze on open savanna. They often follow herds of zebras or antelope, catching insects and small animals stirred up by their hooves. They swallow sand and stones to help grind up their food. Contrary to popular belief, they require a regular water supply. When mating, male ostriches make a booming call and perform a courtship dance for the females. They are polygamous, taking three or more hens as mates. The male scratches a shallow pit into which each female lays up to a dozen eggs, for a total clutch size of up to thirty eggs. This communal nesting behavior is unusual among birds. The male shares incubation with one dominant female. The male sits at night and the female during the day. Ostriches lay the largest eggs of all living birds, seven inches long and three pounds. The eggshell is very tough and hard for predators to crack open. The parent will sometimes lay with its neck outstretched on the ground when danger threatens, giving rise to the legend that they bury their heads in the sand. They may also feign injury to lure predators away from the nest. Newborn chicks are precocial and instinctively know how to search for food. They are full adults by three years of age.
Rheas live in flocks on grasslands in South America. They are similar to ostriches in behavior and appearance, although they have three toes on their feet, as do most of the other ratites. They are brownish in color and can be five feet tall. They are polygamous, but only the male incubates the eggs. Emus live on plains in the Australian outback, and flock nomadically according to rainfall patterns and the resulting food supply. The emu is the second largest flightless bird, nearly six feet tall and eightyfive pounds. It has brownfeathers and a loose, moplike tail. Emus are monogamous. Cassowaries live in the rain forests of New Zealand and northeastern Australia. They are solitary and territorial, pairing only to mate. They feed primarily on fruit fallen from trees. Cassowaries have black, loosely hanging feathers, and the wings are composed only of quills. They have bright blue heads and colorful wattles. A distinctive bony crown on the head called a casque helps them push through the dense forest, and is also used to turn over litter in search of food. Kiwis are elusive, nocturnal birds that live in the forests of New Zealand. They are the smallest ratites, about the size of a chicken. They have round, brown-feathered bodies, short legs, four toes, and run by placing one foot directly in front of the other. Their long, slender beaks have nostrils at the very tip, and are used to probe the ground to locate worms, beetles, spiders and larvae by smell. Males have a shrill, whistling mating call. Females lay only one or two eggs that are enormous in proportion to their body size.
Geographical location: Southern Hemisphere-Africa
Habitat: Semidesert and open plains
Gestational period: One breeding cycle per year; incubation varies from forty days to eighty days
Life span: Ostriches average forty years in the wild, up to eighty years in captivity
Special anatomy: Unkeeled breastbone, tiny wings, unbarbed feathers, solid bones, strong muscular legs
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