Snakes are representatives of reptiles from group Scaly. This group includes also lizards, agamas, chameleons, monitor lizards and geckoes. Snakes have a long cylindrical body, the ovoid or triangular head and a tail, and extremities at them are absent. Skin of snakes is covered with horn scales, various in size, arrangement and a form.
Instruction
1. As well as all reptiles, snakes are diclinous animals. They breed an otkladka of the eggs covered with a leathery cover, however viviparous and yaytsezhivorodyashchy types meet. Fertilization at snakes internal, happens in an organism of a female.
2. Genitals of snakes, testicles at males and ovaries at females, lie in a body cavity, in a tail part on each side of a backbone and open channels in a foul place. The marriage season begins on spring when reptiles wake up.
3. The male aggressively pursues a female, snaps at her for a neck or a back, is twisted around her body and copulates with her. By the end of a marriage season all body of a female can be covered with numerous grazes and stings.
4. Process of pairing at snakes, as a rule, group. The female emits invocatory secretion on which smell all males from the immediate environment run together, and around a female balls with a large number of individuals are formed. However that only who manages to impregnate a snake usually "seals" a stopper of special structure a foul place of a female so nobody else will not be able to impregnate it during this season any more.
5. The eggs laid by a female contain a large number of a yolk and are protected from external damages by a leathery cover. Remain with many species of snakes of egg in the expanded site of a yaytsevod before hatching of cubs of them. Such snakes are called yaytsezhivorodyashchy, boas and some representatives of vipers treat them.
6. Podvyazochny ears, the majority of vipers and sea serpents – viviparous: they also in an embryonic stage eat an egg yolk, but breath of a fruit at them is carried out by means of communication with a metabolism of a maternal organism. The network of blood vessels of a yaytsevod entangles egg, and in a shell oxygen from mother's blood filters.