Atkritumu fish. One dorsal fin. Pelvic fins located on the belly. In the pectoral fins and in most species the dorsal fin is spiny, often jagged rays. Non-rising mouth surrounded by tendrils. The jaws teeth. Body naked or covered with bony plates. Many have an adipose fin.
The inhabitants of the mainly tropical and subtropical freshwaters of South and Central America, Africa and Asia.
The squad consists of 20-30 families and over 1,200 species. 2 family of marine fish.
The Catfish Family – Siluridae
Body naked, elongated. Adipose fin not. The head is flattened, the mouth large, polverini. Dorsal fin short (not more than 5 rays). Anal fin long, not less than 70 rays. These freshwater and brackish-water predatory fish with spring and summer spawning. They live in fresh water in Europe and Asia, in addition to the basin of the Arctic ocean.
The family includes 8 genera, 2 of which are found in our country.
Rod Catfish – Silurus. Antennae 3 pairs. Thorn in the pectoral fin is smooth.
The genus includes 2 species.
Com S. glanis Linne, 1758. Front mandibular barbels shorter than the back. Spiny rays of the pectoral fin is strong (Fig. 110, 1). Reaches a length of 5 m. of residential Forms and the checkpoint form. These fish developed to take care of offspring. Soma build primitive nests from vegetation remnants.Inhabit the waterways of Europe: the Rhine, North to South Finland, and South to Asia Minor. Continue reading
About the brutality of the sharks is legendary. People since ancient times afraid of sharks, because sharks of any size can be dangerous. However, among all the sharks you can highlight a dozen of the most dangerous, which can end badly.
Sharks are dangerous not only because they are strong, have sharp teeth and powerful jaws. The main danger lies in the unpredictability of the behavior of toothy predators: despite the fact that the habits of sharks are being studied for a long time, to predict with accuracy how the shark in any given situation, almost impossible.
Dangerous shark species
Today there are more than 450 species of sharks of different sizes, the smallest can reach a length of 17 cm, the biggest is up to 20 meters. But the real danger to humans represent only some species of sharks. Recent years have witnessed the most attacks on humans great white, bull and tiger sharks.
Great white shark
This shark is called “great”: in length it can reach up to 7 meters and weight up to three tons. The mere sight of this blood-thirsty predator is able to inspire terror. If you watched the movie “Jaws”, then you understand what is involved. The reputation of the great white shark is the most grim: in 2012, the year its victims were 11 people, three cases ended in the death of the victims. Continue reading
The shark is a collective name. There is a white shark, blue, tiger, cat, soup, mackerel, shark-Fox, nurse shark, hammerhead shark. Scientists consider 350 species of these fish. And only 27 of them are accused of attacks on humans. And a few that occur only once.
Thanks to the joint efforts of marine biologists and divers-enthusiasts have managed to debunk some common misconceptions about sharks.
Myth: Most sharks eat people.
Fact: Of the approximately 400 species of sharks in attacks on people were seen a total of about 11. Most sharks are simply too small to pose a threat to humans. But a large white shark people are not too taste, although sometimes they mistakenly attack people, mistaking them for sea lions or seals, which are their favorite prey. Besides, they live at a depth where meeting people is unlikely. Although annually reported approximately one hundred cases of shark attacks on humans, actually elephants are being killed every year twice as many people (about 200) . Dogs kill thousands of people every year!
Myth: Sharks are stupid animals with small, primitive brain.
Fact: the sharks (as the rays) the size of the brain and body comparable to birds and mammals.The research was conducted, which demonstrated that the yellow shark learning is quicker and lasts longer than a cat or a rabbit. This, of course does not mean that sharks are as smart as birds and mammals, but still… Continue reading