Scientists have put forward the theory that the ancestors of whales were mammals that previously lived on land. The structure of the skeleton of these animals living in the sea confirms this hypothesis. They do not look like fish, because they do not spawn, they do not breathe with gills, their cubs are born fully formed and are fed with mother's milk. What are the whales? The size of some representatives of this squad is impressive. Consider them.
Biggest whale
According to some sources, the size of the largest giant was: body length of about 34 meters with a weight of 180 tons. Blue, or, as it is also called, blue whale, according to the classification, belongs to mammals and vertebrates. On average, representatives of this species grow up to 30 meters. They weigh about 150 tons.
The sizes of whales (photo) of other species are more modest. For example, a toothy sperm whale has a body length of about twenty meters, and a killer whale - no more than ten. Dolphins are also cetaceans. The size of these mammals is even smaller. The largest dolphin rarely grows longer than three meters.
Many people consider whales to be big fish. In fact, this is an erroneous opinion. Similar in them is only the general structure of the body and the environment. Significant differences are in nervous activity, blood circulation, skeleton structure, and skin. The reproduction of offspring and its feeding is the same as that of land mammals.
Whales: sizes and varieties
Scientists divide the representatives of these mammals into two suborders. They vary greatly in lifestyle and nutrition. One group is baleen whales, the other is toothed. The names already contain the characteristics of their lifestyle.
Baleen whales are peaceful animals. They feed on plankton and mollusks, filtering them out of the water column through whalebone plates. Most of them in adulthood have a body length of more than ten meters. The species features of the representatives of this suborder and lifestyle are little different.
Toothed whales are predators. Their food is fish and other mammals. This suborder is more diverse. Most representatives have a body size of up to ten meters. Such families are distinguished: oceanic and river dolphins, sperm whales, beaks. In them, in turn, there are divisions by subfamilies and genera, depending on the characteristics of the lifestyle and habitat.
Beluga whale
The tooth whale suborder has representatives that are distinguished by their special skin color. She is white with them. Hence the name Beluga. Animals belong to the family of narwhal. The size of a white whale is up to six meters. The mass of adult males reaches two tons. For comparison: the newborn baby of a blue whisker is approximately the same size.
Beluga lives up to forty years. Hunts schooling fish, crustaceans and mollusks. It lives in the northern latitudes. Features of the species: a thick layer of epidermis and fat, which protects against hypothermia, a “lobed” head and short pectoral fins of an oval shape.
Beluga has a specific color not from birth. Cubs are born in dark blue. At the age of one year, they brighten and become a grayish tint. And only after three years (usually by five years) do they acquire a characteristic white color.
Despite the fact that it is a large animal, another representative of cetaceans, the killer whale, can hunt for beluga whales. Polar bears can also be a threat to them. This happens when beluga whales become dense ice sandworms in wormwood. They cannot be under water for a long time, as they come up every two minutes to breathe air.
Blue whale
This is the largest animal on the planet. Scientists distinguish three types. Two of them: northern and southern - live in different latitudes. The third representative is a dwarf blue whale. Its dimensions are much more modest. An adult reaches only the weight of the calf of its usual counterpart. Dwarf blue whales are quite rare and are found only in the southern seas.
Big animals have everything big. The heart size of a whale is comparable to a medium-sized car; it can weigh up to 700 kg. This is not surprising, because this body is constantly pumping up to 10 tons of blood. The diameter of the giant's artery is 40 cm, and a child can freely crawl into it. The tongue weighs up to three tons. A whale pushes large volumes of water out of its mouth through a whisker, the area of which is more than twenty square meters.
Features
The color of blue whales is actually gray. But if you look at them through the thickness of the water, it seems as if they have a bluish tint. The smell, taste and vision of these giants are poorly developed. But they hear well. Communication is carried out by transmitting ultrasonic signals, and orientation in space - using echolocation.
Is a blue whale dangerous to humans? The dimensions of these animals are huge by our standards. However, they cannot eat a person. They have different eating habits. The diameter of the pharynx is only 10 cm. This is enough to pass plankton, small fish, crustaceans and mollusks. The only harm that a blue whale can cause is to accidentally flip a vessel when it emerges, which will be in close proximity to it.
Cetaceans breathe atmospheric air. They must from time to time rise to the surface for another portion of oxygen. In the normal state, the blue whale sinks for 10-15 minutes. When you ascend during exhalation, a characteristic fountain of water appears.
Habitat and lifestyle
Do Blue Whales Have Enemies? The sizes, as it turns out, do not save even the largest animals on the planet from attack by killer whales. These hungry relatives, huddled in flocks, can attack even a thirty-meter giant. They tear off pieces of meat from the body of a whale. Serious wounds can cause death. There were facts when the carcasses of blue whales with characteristic injuries from killer whale teeth were found ashore. These giants, despite their size and weight, quite often jump out of the water. It is believed that in this way animals try to get rid of mollusks and crustaceans parasitizing on their bodies.
The whale habitat is vast. Scientists do not have sufficient capabilities to track all their movements. It has been established that, depending on the season, blue whales migrate in search of food and optimal conditions. According to other observations, some animals are constantly located in the equatorial part of the Pacific Ocean.
It is believed that the life expectancy of blue whales can reach hundreds of years. They are loners. Only sometimes they gather in small groups during seasonal migrations. Mother feeds her cubs for at least six months. During the day, the growing "baby", weighing up to ten tons, can drink 600 liters of mother's milk.
