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
Poisonous fish on the planet much more than poisonous snakes – more than 1250 species (snakes – 410). And every year ichthyologists discover new dangerous species. In this article we are not talking about the exotic inhabitants of the tropical seas, and about ordinary Russian fish living in our rivers. That’s only when you try to use this trivial-looking production in food from fisherman might suddenly begin diarrhea, headache, hallucinations, and other troubles, including death.
Easy Russian fish
Let us first clarify what classes can be divided poisonous fish. So, they are primary and secondary toxic-poisonous. What does it mean? That means there are fish, like snakes produce venom in special glands or by its nature containing in the body dangerous products of metabolism, that is, initially-poisonous.
To secondary poisonous fish are able to accumulate in their bodies a poison contained in the environment. Such environments can be living in the pond poisonous algae or, even worse, fall into the water of toxic human waste.
And if the second paragraph is all clear, and to protect yourself from poisoning very easily (just not enough to catch and certainly not to eat fish caught in suspicious ponds), initially-poisonous things are much more complicated. We begin our story. Continue reading
Reproduction and spawning
Reproductive behavior of tropical marine fishes is poorly documented because only a few species breed in captivity. However, some – such as clowns, gobies and seahorses to breed relatively simple. Others, like coral fish may spawn in the aquarium but the fry are so immature that they are very difficult to grow.
To ensure availability in the aquarium at least one opposite-sex pairs marine fish breeding is almost impossible, because in most species males and females are externally indistinguishable just. However, if you keep the fish in the pack, their behavior will help you to determine the sex charges. If two identical fish fight is most likely male contesting territorial rights. If two fish are related to each other friendly, it can be compatible in a female and male. Unusual swimming movements or postures may not be indicative of flirting – so, in your aquarium just got a couple. In the mating season sometimes appear insignificant physical differences: the female has, of course, the belly is inflated from the calves. Males often intensifies the color, and the picture loses clarity. Some species are able to change their gender, what does not prevent, but rather contributes to the search for a pair for spawning. For example, all multiclone – males, but if you have a small group (two individuals), the dominant fish will become the female and will mate with the nearest dominant male. Kood I-frames and some coral sex change occurs in the opposite direction: the dominant individual in a purely female group turns into a male. Continue reading