Seival - description, habitat, lifestyle

Balaenoptera borealis - this is how Latin is called a large marine mammal that belongs to the family of stripes. It is also called the Sidyana whale, the seyval or the Willow whale. Only such representatives of the whales as the fin whale, humpback and blue whales are larger than it.

Seivalas live mainly in the oceans, they also prefer the deep seas, where they use mostly remote strata of water.

Basic description

On average, the size of this animal is from 12 to 15 meters, but there are also larger individuals that can reach 20 meters - this is the record for this period. In size, females, as a rule, slightly outnumber representatives of male saves.

In form, the ivase whales are elongated and rather slender, with a flat and large flattened tail, which passes into the body through a thin isthmus.There are also rather short pectoral fins and an elongated muzzle. And the dorsal fin has a sickle shape and size is from 25 to 61 centimeters. The color of the body is mostly dark grayish, but there are splashes of white.

On the upper part of the mouth is located more than 300 plates of black whalebone. The inner bristles of each plate have a light shade.

The spread of saves

This whale prefers coastal areas, but does not appear frequently on the surface. Nearby from the coast, the Willow representatives choose depths of tens and hundreds of meters, where they go down for swimming.At the same time, they are not particularly professional divers, since every 5-10 minutes it takes to emerge in order to get a new portion of air.

Nutrition and behavior

However, in order to eat, the saves float to the surface and begin to swim on their side through flocks of predators. They feed on whalebone with the capture of food. Get about 900 kilograms of small fish, crustaceans, amphipods, copepods and small fish daily.

The behavior of seivals as social animals is not fully studied for this period. As a rule, they move in relatively small groups of up to five whales, but it is also possible to notice large concentrations of saves where there is a lot of food. With abundant food, the region is able to attract groups of up to a thousand individuals, which act fairly smoothly.

Also large groups are formed during the migration period. Flocks of saves are one of the fastest in the whole ocean; a single whale can reach speeds of up to 50 kilometers per hour.

Breeding

It is also quite difficult to provide accurate data regarding families of saves.According to some sources, males and females form pairs and act as a generalized social unit during the breeding season, however, we repeat, accurate information about how these whales exist as families is extremely scarce. In winter, mating occurs, the individuals that live in the northern hemisphere mate between November and February, and the inhabitants of the southern hemisphere reproduce from May to July.

The pregnancy of the female lasts from 10 to 12 months, and ends with the birth of a cub of 4.5 meters in size. Also possible and large families, which is quite rare.

During the first 7 months, the cub feeds on mother's milk. At 10 years, the young whale becomes sexually mature, and reaches its maximum body size at 25 years. Females give birth annually, however, the current situation in the world's oceans probably reduces this intensity, and saves may give birth intermittently for a certain number of years.

There is also a sharp decline in the number of saves due to human factors. People regularly destroy a fairly significant number of these whales, and this fact also affects their reproductive activity.On average, the earthly (or rather water) path of the seyval is about 72 years.

The value for a person and the safe status of the seyval

Previously, these whales were actively used in whaling and brought significant income, now their value is decreasing. In many ways, this fact is caused by the behavior of the people themselves, who in a certain period were actively extracting seivals, which provoked not only economic growth in this industry, but also a significant reduction in the population, which was practically catastrophic. The consequences of such human expansion are still being felt.

The fishery began actively in 1950, and in about 15 years reached its maximum development, when more than 25 thousand individuals were destroyed. By the end of the 1970s, the global catch of safes was reduced to 150 individuals annually. During this period, about 57 thousand individuals live in the ocean.

It should be noted the tendency to population growth, which is achieved due to the reduction of the population of fintails and blue whales, which also belong to this family, respectively, have intersecting rations and habitats.However, this statement requires additional confirmation, and, in fact, is not optimistic, since it still speaks of a decrease in the whale population in the world's oceans. At the same time, the range of food overlap between saves and other species of whales (in particular, the blue and finvalles noted earlier) is incomplete, therefore conclusions about the mutual influence of the population size should be considered deliberately.