Snake is a suborder of reptiles. Harmless and very dangerous for human toxic representatives are of the variety snakes. Snakes have mastered almost all the living spaces of the Earth, except by air. There are snakes in all continents except Antarctica. These reptiles spread from the Arctic Circle in the north to the southern tip of the American continent. Especially numerous snakes are in the tropical regions of Asia, Africa, South America and Australia. Snakes prefer to live in areas with hot climates. They live in different environmental conditions - forests, steppes, deserts, foothills and mountains. The snakes are mostly terrestrial life, but some species live underground, in water, on the trees. Snakes hibernate during adverse conditions, such as by cooling. This is one of their features. The entire known snakes are predators. They feed on a variety of animals: vertebrates and invertebrates. Nonpoisonous snakes swallow prey alive or previously sacrificed her, clenching his jaw and crushing the body to the ground (slender snakes) or strangling in the rings of the body (boas and pythons.) Poisonous snakes kill prey by introducing poison into her body through specialized teeth. Snakes tend to swallow prey whole. Swallowing mechanism is alternately moving left and right halves of the mandible (the snake like pulls itself on extraction). This is another important feature of these reptiles. The skull of snake differ most strongly developed kinetic movement. There are many bones of the skull are movable relative to each other. Such a system is movably jointed bones contributes to an extremely wide mouth uncovering the need for swallowing large prey whole. All this allows the snake to swallow very large prey relative to the size is often greater than the thickness of the trunk snakes. The internal organs of these reptiles have an elongated shape and are arranged asymmetrically. In addition, some of the paired organs have lost one-half. Good sense helps snakes to easily find prey. The esophagus of snake is very muscular, which facilitates pushing food into the stomach. It is a long bag, rolling in a relatively short intestine. The eyes are protected by a "lenses" - fused transparent lids. External ears are absent, but the snakes feel vibrations from the ground and the sound in a fairly narrow range of frequencies.
|
|