norafly Killer whales the large marine mammal known for its predatory nature. Orcas should not be confused with the whale — this word denotes one species of swallows, the word of the killer whale call of the wild duck and several species of catfish. Killer whales represent an intermediate form between dolphins and whales. The world knows only 3 species of whale: a large whale, which is more often simply referred to as the orca without an adjective, small, or black whale and pygmy killer whale. The last two species are little known.The size of the three types of strong different. The largest species reaches lengths of 8-10 m, the weight of the animal comes up to 8 T. the false killer whale has a length of 5.6 m and weighs no more than 1.3 t, the pygmy killer whale has a length of only 2.4-2.5 m, its weight is calculated a couple of hundred pounds. Features of the structure of killer whales are similar to both whales and dolphins. The figure they are closer to the Dolphin: compact, dense, not too stretched body, long pectoral fins rounded. Dorsal fin of the killer whale is at the middle of the body, it is very large, acute, with a groove at the rear edge (in dwarf orcas more blunt and short). But in contrast to these dolphins at the orcas there is an elongated rostrum ("beak"), the end of their snout is rounded and blunt. This way they are similar to whales as well as whales orcas allowed water fountains when you exhale. In the English language for these animals got the name of the killer whales, but in spite of it systematically orcas are closer to dolphins. The internal structure of killer whales does not differ from other cetaceans. They have also developed auditory parts of the brain, they use a wide range of sounds to communicate and have the same ability to echolocation. The orcas teeth sharp, conical, and relatively large, this allows them to tear large pieces of prey. Between the different species of whales in addition to the dimensions differ by color. Big black whale, the lower jaw and belly she white, two spots on the sides at the rear part of the body merge with the white stripe on the belly, two small spots behind the eyes. Small killer whale entirely black, dwarf — black with a single white spot near the anus. Sexual dimorphism in these animals is weak: only large killer whale males have behind dorsal fin white spot, which is absent in females, in addition they differ in the shape of the dorsal fin, in other species the difference between the sexes boils down to the larger size of males.Dolphins are not fish, as many believe, but aquatic mammals of small size, belonging to the order Cetacea. The dolphins are in direct relationship with whales and killer whales (the latter are actually large dolphins). Very distant cousins of dolphins can be considered pinnipeds and terrestrial predators leading aquatic life (sea otters). This group of animals is extensive and diverse and includes 50 species.Bottlenose Dolphin (Tursiops truncatus).Common features of all species of Dolphin are bare, streamlined body, lithe and muscular at the same time, highly modified limbs into fins, a small head with a pointed snout and dorsal fin, which is most of the dolphins. At the head of these animals is well-marked transition between the frontal part and the nose. Small eyes and see the dolphins is bad, because it does not use vision to hunt prey. They also possess no tactile vibrissae and olfaction. The nose as such in our understanding of dolphins there. The fact that dolphins are so adapted to permanent life in water, the nostrils they have merged into one breathing hole (spiracle), which is... scalp. This allows the animal to breathe when their body is submerged in water almost completely. In addition to nose dolphins have no ears. But hearing they have, it just operates in an unusual way. In the absence of external auditory openings the perception of sounds took on the inner ear and airbag in frontal part of the brain, which act as resonator. These animals have perfect echolocation! They catch the reflected sound wave, and thus determines the location of the object. The nature of sound vibrations dolphins also determine the distance to the object and its nature (density, structure, material from which it is made). It is no exaggeration to say that the dolphins literally see the world through the sounds and see it much better than the rest of the creatures! Yourself dolphins make sounds like POPs, clicks, clatter, and even chirping. The sounds made by dolphins are extremely diverse and complex, they are composed of many individual modulations and animals are used not only for communication but also for communication with the outside world. The teeth of dolphins numerous (40-60), fine and homogeneous. Such a structure of the dental system is due to the fact that the dolphins only catch the prey but not chew it.