Each living being on Earth seeks for continuation some kind of, and a shark, of course, not an exception. But the way of reproduction of these marine animals differs from how other representatives of their look breed.
Shark and her role in planet fauna
The shark is fish who is an absolute predator. It serves as a peculiar regulator not only the number of inhabitants of the sea abyss, but also the hospital attendant as weak or sick individuals become its victims, as a rule. Besides, the shark serves as a stimulator to improvement and self-development of those whom she eats. Wishing to be protected from a predator, inhabitants of the seas and oceans seek to improve the camouflage qualities, learn to gather high speed of movement, that is evolve. And to regulate population of sharks and to keep population of its potential victims, the nature provided activity of reproduction and that and others. And the shark in this formation is not on the first place – she breeds much more slowly, than other fishes.
As sharks breed
Sharks treat as the structure of a skeleton cartilaginous fishes and breed, like the relatives, by means of so-called internal fertilization at which sexual products of a male are entered into a body of a female and already there is a conception of embryos.
As emergence of posterity on light of a shark are divided into three main types – yaytsekladushchy, yaytsezhivorodyashchy and viviparous. Yaytsekladushchy sharks at the same time have a formation from 2 to 12 eggs which they suspend small groups on seaweed. The shell of eggs very strong and reliably protects cubs from mechanical damages and encroachments of other predators. At yaytsezhivorodyashchy sharks the development of egg and a rupture of a shell happens in utero. After "birth" posterity still some time is in mom, and comes already almost created individuals capable to independent full existence to light. At viviparous females of sharks the conception, growth and development of embryos happens without formation of a shell. Such way of reproduction corresponds to the highest type of the organisms inhabiting the planet Earth. More than 10% all of them types concern viviparous sharks, and at them at the same time are born from 3 to 15 cubs.
The interesting facts about eggs of a shark
Shark eggs often have very unusual form and call them "the mermaid's purse". Oceanologists found a laying in which all eggs were placed in the cover reminding a sack which cavity was filled with collagenic weight. In one egg of a shark there can be at the same time several germs, but only one of them, most the strongest survives. And in the course of the development in egg he eats the weaker fellows. The sizes of shark egg fluctuate from the sizes of goose egg or a human palm to the extended spheres up to 2 meters long.