Everyone has long known that birds are capable of flying. This characteristic distinguishes them from other animals. But some of them do not know how to fly at all - they are ratite birds. Their structure has significant differences from other animals of this class. What are the characteristics of ratites, whose representatives are quite widespread on the planet? Let's answer these questions together.
Subclass ratites
One of the characteristics of birds, which determines their ability to fly, is the presence of a keel. It is a flat outgrowth of the sternum, to which the muscles that drive the wings are attached. The ratites, whose list is large enough, do not have such a part of the skeleton. Accordingly, they do not know how to fly.
Beakless birds move only on the ground, quickly running or walking. Therefore, they all have powerful and long legs. Beakless birds have underdeveloped wings. The exception is only kiwi, which they are completely absent. Their habitat is open spaces or thickets of evergreen shrubs. All of them are brood birds. Therefore, their chicks are born with open eyes and are covered with fluff. After a short amount of time after birth, they leave a cozy nest and learn to look for food and live independently.
And now let's get acquainted with the species diversity of ratites, which are combined into four orders.
Ostrich-shaped
The largest of the existing representatives of this class belongs to ratites. Its weight can reach 90 kg, and height - 270 cm. This is none other than an African ostrich. He has another record property - to develop speed while running up to 70 km / h. The African ostrich has a long neck, a flattened head and only two fingers on each leg. It also promotes fast running.
Another representative of this detachment of ratites is the Nanda, which lives in the vastness of South America. He also eats plant foods and small land animals, developing a significant speed during the hunt for them.
Nanduide
The ratites, whose representatives do not fly, have certain systematic structural features. For the Rhea, this is the presence of three fingers on each leg and almost imperceptible wings. However, during a quick run, the bird raises one of them, like a sail, using it as a navigator when moving. In addition, on the wings of these birds there are hard and sharp outgrowths - claws. Their nanda is used during courtship games to intimidate rivals. Birds run very fast, they can even jump a ditch several meters long. Compared to ostriches, the nandus are much smaller. Their height reaches one and a half meters. Birds live in small flocks, eating plant foods.
Cassowary
In the vastness of Australia and New Zealand you can meet cassowary. If you translate this name from the ancient Papuan language, it will mean "horned head." And indeed, on their head is a kind of helmet. It is formed by a connective spongy tissue, covered on top with a horny substance. Scientists suggest that the bird uses this device to spread the branches of the bush, making its way through the thickets of rainforests. The neck of the cassowary is devoid of plumage, while it is painted in very bright colors - from blue to orange. Surprising is the fact that the female, laying eggs, leaves her nest. And the male incubates them. The eggs of the cassowary themselves are amazingly saturated colors: from olive to almost black.
Kiwiformes
The beskilevye birds, the list of which we continue, can be of very small sizes. For example, a New Zealand resident kiwi weighs a little more than three kg at a height of 55 cm. They have practically no wings, four fingers on their feet. Kiwi eats small invertebrate animals, which they find in the soil with a thin and long beak. These birds prefer to live in tropical forests, hiding from dangerous predators in the dense vegetation of evergreen shrubs.
The value of ratites
Of all ratites, ostriches are of particular importance. So, African ostriches have been hunted for a long time because of the beautiful feathers of males and delicious dietary meat. Such illegal fishing has led to a significant decrease in the number of these birds. Currently, in many countries of the world ostriches are bred on special farms. Here, these ratites are used to produce several unique products at once. Firstly, it is meat, which is recognized by nutritionists around the world as the most useful due to its low content of cholesterol and fats. The next valuable product is the skin. With its special treatment, patent leather is obtained, which is valued more expensive in the market than crocodile and snake. People began to use ostrich feathers in the 18th century to decorate hats, make fans of various sizes, and clean various parts of equipment. Ostrich eggs are also unique. They are the largest among all birds. Some specimens even reach a couple of kilograms with a shell thickness of up to half a centimeter. And thanks to the large size of birds in the USA and Africa, they even arrange ostrich races, harnessing them to real teams.
Cassowaries and emu are also of great economic importance in the Americas, as well as Australia. Here they are bred for meat, skin and fat, which is used in the manufacture of cosmetics, biological additives and medicines.
Beakless birds lack flight ability. Their typical representatives are ostriches, kiwi, emu and cassowary. These birds are united by the presence of rudimentary or underdeveloped wings, the absence of a keel and the ability to run fast.