The Number – Cypriniformes
Family – Priniv
The genus/Species – Serrasalmus nattereri
Length: average 20 cm, in some species up to 50 cm.
Mass rarely exceeding 1.5 kg.
Caviar: a few thousand eggs.
The incubation period is 10-15 days, depending on water temperature.
Habits: constant float huge flocks.
Food: primarily fish; attack mammals, floating or come to the waterhole, and birds.
18 known species of piranhas, 4 of which are dangerous to humans, although fatal cases have been identified. Continue reading
Hundreds of thousands of years ago, long before the appearance on Earth of man, the oceans already swam fish. At that time they were the most highly developed creatures.
Since then, they began to develop a variety of ways so that now only some species only vaguely resemble the first primitive ocean fishes.
As a rule, fish has an elongated and tapering shape. People have copied it in the construction of ships and submarines, as it is the best adapted to movement in water.
Most fish use their tail as a motor. With the help of fins and they control their movements. Except for one species of fish, all the others breathe by means of gills. Fish swallows mouth water that passes through the gills and out through the hole. Water also contains oxygen, and it through the gills into the blood of fish, as the air through the lungs in the blood of man. Continue reading
Floating jellyfish in the sea often struck by its beauty. Such a wealth of shapes, colors, as among the jellyfish, not to meet many animals! Jellyfish inhabit all seas, and some of these sea animals prefer warm waters of the tropics and subtropics, while others liked the cool Northern parts of the oceans.
Some jellyfish can be found at a depth of 10km, and there are jellyfish that do not leave the coastal strip. It is noteworthy that each type of jellyfish is found only on the territory of the area is an animal does not apply to pandemic, that is common everywhere.
The largest jellyfish is Cyanea arctica – chosen by a cool North sea. The age of lanei can be identified by its colour – older individuals are covered with brown and red spots; the young specimens are painted in an intense orange color. Continue reading