The Black Sea dolphin. Types of dolphins

These marine mammals are the smallest of the order of cetaceans. Today, scientists have about fifty species of dolphins.

Description

These marine inhabitants belong to the subfamilymammals, a cetacean group, a family of dolphins. Their body length ranges from 1.2 to 3 meters, in some species it reaches 10 m. Almost all species of dolphins have a fin on their backs. And also extended in the "beak" muzzle and a huge number of teeth (more than 70).

Dolphins in the sea are guided by echolocation. Animals have a very delicate hearing - they can hear sound vibrations from a few tens of Hz to 200 kHz.

Dolphins are endowed with complex voice alarmsand sonication, the echolocation organ located in the nostril (single). Six air bags with a system of muscles are connected to it. The frequency of the emitted signals is about 170 kHz.

It is necessary to say also about the highly developed centralthe nervous system of these animals - a large brain, spherical, its large hemispheres have numerous convolutions (the cortex of the dolphin brain has 30 billion nerve cells). Such brain sizes allow dolphins to process a large amount of incoming information: they can, like parrots, copy words that a person utters.

Hydrodynamic body shape, antiturbulentthe properties and structure of the skin, the hydro-elastic effect (adjustable) in the fins, the unique ability to dive to an immense depth and many other features of dolphins have been interested in the supporters of bionics for decades.

These cute animals are found in manyDolphinariums and oceanariums, as they are easily trained and amenable to training. Today, many kinds of dolphins "work" in the circus. Now the possibility of domestication of certain species of these animals is being considered.

Unfortunately, in many countries they are the subject of fishing (for example, short-headed dolphins in Japan, prodelfins). In our country, the fishing of these animals was banned as early as 1966.

The topic of our conversation today is the Black Sea dolphin. We will present to you three main species of these marine inhabitants.

Afalina, or the big dolphin

This is the most common and most studied species, which is often found in the Black Sea aquariums. Afalina is a dolphin, which is easier than others to tolerate bondage.

These marine mammals grow to 3 meters and gain weight of 300 kilograms. This Black Sea dolphin is active during the day, it rests at sunset.

Hunt dolphins for fish, but they will not refuse fromshrimp, squid, cephalopods. Hunting for schooling fish, dolphins are grouped together. Seeking rays and mollusks, they descend to a depth of more than 300 m.

Afalina is a dolphin that consumes dailymore than 15 kilograms of fish. They have few enemies - they are big killer whales and sharks. Significant damage to the population is caused by a person. In fishing nets, animals are often confused and die. Echos of sea vessels are also involved in the death of dolphins. The fact is that they are guided by the so-called locator.

Under the water, the sounds of dolphins spreading fromhigh speed, reflected from objects and returned back. Thus, the animal receives information about the object of interest. If he feels a "strange" sound wave of the echosounder, then it can get lost in space. Often they jump out into the shallows. There are many such examples, such cases often occur on the routes of sea-going vessels.

Dolphin sounds

Ichthyologists, studying bottlenose dolphins, found out that theyare distinguished by a wide range of sounds that are used for communication inside the pack. After analyzing the records of the "negotiations", the scientists came to the conclusion that there are 17 sounds in the "lexicon" of the bottlenose dolphins. Pursuing their prey, they "bark" when they eat food - "meow", and when they intend to intimidate an opponent, they make sounds resembling claps. Five of them understand the Black Sea dolphins of the white-cap and grinda. The remaining 12 sounds are completely unique. Trainers say that different combinations of these signals allow animals to communicate with a person.

Reproduction of bottlenose dolphins

Spring and summer, dolphins marryperiod. At this time, animals behave completely differently than usual - they flex all over their body, take special poses, sniff each other, jump, stroke each other with fins and heads, and squeal.

The smallest sexually mature female, measured by ichthyologists, had a body length of 228 cm. The pregnancy lasts about a year.

Afalina, like most cetaceans, is a viviparous animal. A baby is born in water, usually with a tail forward. Births last sometimes 20 minutes, and sometimes are delayed for two hours.

Belobochka - an ordinary dolphin

These are the most social animals from their family. They do not represent their lives alone. The flock of dolphins in some cases reaches the number of two thousand individuals.

Belobochki create a family consisting of several generations of the offspring of the same female. Lactating females with young animals and males sometimes form separate, often temporary jambs.

These are the fastest marine animals developingspeed up to 60 km / hour. Which is easy enough to explain. Belobochka is a small dolphin. The length of his body does not exceed one meter. They can not even keep up with the shark.

Flocks of dolphins live mainly in the open sea. They feed on fish, shellfish, sometimes crustaceans.

Habitat

It is commonly believed that this dolphin is Black Sea,although it lives in virtually all seas and oceans with temperate or warm waters. According to scientists, the white-bellied dweller living in the Black Sea is the standard of "delphine beauty".

External Features

This animal has a proportional, slenderbody. On the sides is a rather complex drawing - a horizontal eight on a white background, which gave the name to the mind. Color - black and white, as well as various shades of gray.

Behavior in nature

Belobochki are very friendly animals in oneflock. They take care of sick fellows, jointly hunt fish, protect and protect young dolphins. Communication in the pack takes place with the help of sound signals - clicks, peep and gnash. In contrast to the bottlenose dolphin, the lollipop uses 5 sounds of different frequencies, tonality and timbre.

In winter, dolphins gather in large schools,reaching several thousand individuals. By the summer they usually disintegrate, and the blondes create small groups. In such families - a very close relationship between all its members.

There are cases when these dolphins helped the old animals to stay on the surface of the water so they could breathe.

Dolphin brewing

This species has several names - the Azov dolphin, the usual sea pig, the pig, the Azov sea porpoise, etc. This is another (of the three most common) dolphin Black Sea.

External differences

The dolphin of the Black Sea azovka has a shorthead with a blunt, rounded muzzle, which has a powerful fat pad. The body of the dolphin has a cigar-shaped shape, a triangular dorsal fin with a wide base. Pectoral fins slightly rounded. The back is painted dark gray, the belly is almost white. The length of this animal does not exceed 1.8 m. Its weight is 30 kg.

Habitat

Dolphin Bordering on the shores of the Black Sea occurs throughout the year, off the coast of Azov appears in early spring. In autumn these animals leave after the jambs of the atherin and anchovy.

In some years, a sharp cooling and even glaciation of the Azov Sea led to the death of these animals in the ice.

They usually hibernate along the shores of the Caucasus and South Crimea. These dolphins live in small groups of 5 to 30 individuals, but there are also single individuals (quite rarely).

In the summer, bats can be seen in the Kerch Strait, where they hunt for a cedar. This dolphin often goes to rivers.

Life expectancy is 12 years, puberty comes to 4 years. Pregnancy lasts about 11 months, cubs are born in May-August. The female feeds offspring for 5-6 months.

It feeds on gadflies, hamsoy, atherin and other small fish. Every day the dolphin feeds more than 5 kg of fish.