Everyone has long known that birds are capable of flight. This characteristic feature distinguishes them from other animals. But some of them do not know how to fly at all - these are ratites. Their structure has significant differences from other animals of this class. What are the characteristic features of ratite birds, whose representatives are quite widespread on the planet? Let's answer these questions together.
Subclass ratites
One of the features 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 set the wings in motion are attached. Riteless birds, the list of which is quite large, do not have such a part of the skeleton. Accordingly, they do not know how to fly either.
Rateless birds move only on the ground, running or walking fast. Therefore, they all have powerful and long legs. Riteless birds have underdeveloped wings. exceptionis only kiwi, in 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 down. A short time after birth, they leave the cozy nest and learn to find food and live on their own.
And now let's get acquainted with the species diversity of ratites, which are combined into four orders.
Ostrich
The largest of the extant representatives of this class belongs to the ratites. Her weight can reach 90 kg, and her height is 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 toes on each foot. It also encourages fast running.
Another representative of this detachment of ratites is the rhea, which lives in the expanses of South America. It also feeds on plant foods and small land animals, developing considerable speed while hunting them.
Nandu-shaped
Rateless birds, whose representatives do not fly, have certain systematic features of the structure. For nandu, this is the presence of three fingers on each leg and almost imperceptible wings. However, during a fast 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 nandu are used during mating games to intimidate rivals. Birds run very fast, they can even jump over a moat several meters long. Compared to ostriches, nandu are much smaller. Their height reaches one and a half meters. Birds live in small flocks, eating plant foods.
Cassowaries
In the vastness of Australia and New Zealand you can meet cassowaries. If this name is translated from the ancient Papuan language, it will mean "horned head". Indeed, on their head is a kind of helmet. It is formed by a connective spongy tissue, covered on top with a horn-like substance. Scientists suggest that the bird uses this device to push apart the branches of the bush, making its way through the thickets of tropical forests. The neck of cassowaries 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 hatches them. The cassowary eggs themselves are amazingly rich colors ranging from olive to almost black.
Kiwifruit
Rateless birds, the list of which we continue, can be quite small. For example, the inhabitant of New Zealand kiwi weighs a little more than three kg with a height of 55 cm. They have practically no wings, there are four fingers on their feet. Kiwi feeds on small invertebrates,which they find in the soil with the help of a thin and long beak. These birds prefer to live in tropical forests, hiding from dangerous predators in the dense vegetation of evergreen shrubs.
Meaning of ratites
Of particular importance among all ratite birds are ostriches. So, African ostriches were hunted for a long time because of the beautiful male feathers 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, this is meat, which is recognized by nutritionists around the world as the most useful due to its low cholesterol and fat content. The next valuable product is the skin. With its special processing, patent leather is obtained, which is valued on the market more than crocodile and snake skin. People began to use ostrich feathers as early as 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 of 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 emus are also of great economic importance in North and South America, as well as Australia. Here they are bred formeat, skin and fat used in the manufacture of cosmetics, dietary supplements and medicines.
The ratites lack the ability to fly. Their typical representatives are ostriches, kiwis, emus and cassowaries. These birds are united by the presence of rudimentary or underdeveloped wings, the absence of a keel and the ability to run fast.
