the whales is despite its fish-shaped external proper mammalian, who developed into pure water-inhabitants from four-legged, country-living in predecessors. In it, individual adaptation-steps of the tribal-history clearly still become onto-genius, the Keimesentwicklung of Walembryonen. Very young fetuses still have the installation of 2 pairs of extremities, also the nose-opening still is because of the head in front.
Shape Adult whales don't have any more rear-extremities; even the basin is receded until on one small rest. The breath-opening lies on the head, usually at the highest place, far above. The locomotion takes place with whales through on - and reduction of the horizontal tail-flukes, whose surfaces always are diagonally inclined to the longitudinal-axis of the Wales. Both the tail flukes and those (with most types existing) back-Finn are connective tissues without bone-skeleton.
The rear part of the whale-body is compressed at the side and hardly offers the water resistance when on and kicking the ball out, so that advantage is almost taken from the entire strength of the movement to the propulsion. The body of the whales, streamlined anyway already, doesn't carry any hair (exception): few bristles and Sinneshaare at the head, and has - as one explored at dolphins - through the soft sub-skin even further current-technical advantages. Little one turbulences of the past-streaming water are "swallowed" by local distortion of the skin-region lying under it so that the friction-resistance remains low. Z explains this. T., why almost easily just as fast the relatively small dolphins how the gigantic furrow-whales (40-50 km per hour) can swim.
Back and flippers serve the stabilization when swimming; if whales get into too flat water or at country, so they are completely helpless. The big types are crushed by its net weight practically on that occasion as soon as the buoyancy of the water is missing. The flippers of many whales still show the original five-ray-y skeleton-construction of the typical mammal-extremity.
In adaptation to the water-life, there are many further Umformungen of the whale-body: Ear-mussels are missing completely; It is means and inner-ear from the remaining skull acoustically isolated so that both ears can pick up sound-signals independently of each other (without transfer through body-sound) to the spatial hearing.
Whales have a multiplicity of Z at their disposal. T. very much hochfrequenten tone-remarks, with which they communicate among each other and orient also after the sonar-principle (Echolotung). The optical sense resigns opposite the acoustic one with the bearings in the sea. Nevertheless, most of the whales of properly well developed eyes, with which they can see also over water - at least over shorter distances -, have quite well. A tough, greasy secretion of the tear glands protects the eyeball from the effect of the saltwater.
The brain-sections (with fossil Urwalen still existing) responsible for smelling are completely receded with the present-day forms. A thick bacon-layer, the "bubbles", protects the whales from cooling; surplus heat - approximately with fast Dauerschwimmen - is led away through widely ramified blood-vessels in the flippers. Whales lack perspiration and tallow-glands completely.
Dive Strongly branched blood-vessels (so-called miracle-nets) at different places of the whale-body provide also a relative pressurization between individual body-parts with the Tieftauchen. Approximately 70 percent of the Erdoberfläche is covered from water, from it on the other hand is 83,9 percent deeper than 2000 m (4,2 percent 2000-1000 m, 4,3 percent 1000-200 m, 7,6 percent 200-0 m). The average-depth of the seas therefore amounts to 3800 m.
Through its adaptation to a diving way of life, the whales opened up gigantic food-reservoirs for itself consequently. However the obstacles are diverse: 10 m water-column practice 1 pure pressures; the pressure-difference alone between head and tail of a diving blue whale of 30 m of length amounts devoid of 3.
The diving whale must be able to endure the often extremely low temperatures of deeper water-layers longer time; also, it must locate its loot-animals in the almost lightless depths.
There are two in principle different adaptations of whales to diving: The not deeply diving dolphins have very big lungs, whose vital-capacity is nearly immediately big like the entire lung-volume. Also, the fine ramifications of the Bronchien with many valves are lockable against each other.
The deeply diving whales against it (Z). B. Pottwale, has an only low lung-volume, its oxygen-demand is met from the blood and the red muscle-dye of Myoglobin, that are much more strongly concentrated in the whale-muscle, as in the muscles of other mammals.
The heart attack-frequency sinks during the diving-process strongly, the blood circulates no more so strongly in the entire body but looks after the oxygen-needy brain mainly from the storing vessel-systems out.
The breath-center is much less sensitive for high Kohlendioxid-Konzentrationen in the blood and tissue of the Wales as with other mammals.
The bulk of the whale-body consists of hardly komprimierbaren, liquid-been filling tissues; the anyway small lungs are komprimierbar strongly. Free breath-air dissolves in the surrounding tissues of the breath-ways. Since whales under water don't take any compressed air like appliance-divers to itself, they hardly are exposed to the dangers of the diver-illness and with it embolisms.
The thick Blubberschicht protects it from the deadly cooling.
Reproduction Whales usually deliver 1 individual young months-long 11-16; Twins are very rare. The young whales make progress with the tail to the world and immediately are steered to the surface by (with the porpoise) its mother in order to breathe. Initially, the female lies down on the side, so that remains the suckling kid with its Blasloch at the surface; soon, it can be nursed also under water. This process probably is similar with all whales. The milk-glands lay 2 export-walks, that hidden beside the sex-opening in pleats. From big reserve-areas, the milk is out-pressed by muscle-contractions of the mother very fast all at once.
System The order of the whale-animals includes 3 subordinations: The Urwale (Archaeoceti), eldest findings from the low Eozän, died out in the oligocene. Today, the Bartenwale and the tooth-whales still live.
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