What kind of animals are dolphins? Why do people have a special sympathy for them for a long time? Yes, and dolphins are very friendly to people, showing great interest. There are many cases of rescue of drowning people by these creatures. They lend themselves perfectly to training, as they are very intelligent and have incredible quick wits. About what animals dolphins belong to will be discussed in the article. And also about where they live, how they breathe, and about their other features.
Dolphins are not fish
Dolphins are not fish. Although outwardly they are very similar to them in their form. Dolphin - a class of animals related to mammals. They are part of the order of cetaceans, suborder of toothed whales. And also they are divided into sea and river. Sea dolphins are called dolphins, and river dolphins are called river dolphins, or freshwater.
The first swim in the open seas, onlysometimes swimming in the mouths of large rivers. The latter are much less common, they are mainly found in fresh inland waters. But occasionally they penetrate into saline estuaries (flooded mouths) and coastal marine areas. The most common of the sea dolphins are common dolphins and bottlenose dolphins. Let's look at them in more detail later.
General Description
Dolphin is a marine animal whose body has an oblong shape, which allows it to literally glide through the water at a speed of about 50 kilometers per hour. Oily skin secretions also favor this. The length of individuals ranges from 2 to 4.5 meters, and weight - from 150 to 300 kilograms.
In most cases, there is a fin on the back, mostly in the form of a sickle. The mouth resembles a beak, the number of teeth can reach 272, which is a record for mammals. The teeth are like sharp spikes, perfect for holding slippery fish.
Dolphins have small eyes and poor eyesight. The nostrils as such are absent, instead of them there is a drawbar on the crown of the head. Dolphins stay in the water for a long time, but periodically rise to the surface to take in air.
How do dolphins breathe and sleep?
Dolphins are a group of animals that lack ears. However, they have a hearing, although not in the usual sense. Sounds are perceived by dolphins through the inner ear and air sinuses in the forehead, acting as resonators. Dolphins are animals that possess echolocation. They can, without the slightest error, determine where the object is located and what its dimensions are, by the reflection of it.sound. And they calculate the distance by the wavelength.
The hallmark of dolphins is the fact that they never completely fall asleep. They only rest, freezing in the water column, and from time to time swim to the surface to breathe. Dolphins turn off each hemisphere of the brain in turn, so they are always half awake.
Communication and food
Dolphins are socialized animals, they gather in packs that can number from ten to several thousand individuals. This makes it easier for them to defend themselves against enemy attacks. Mutual relations in flocks are characterized by peace and tranquility, lack of competition.
Dolphins "talk" with a wide variety of sounds that can be described as whistling, barking, chirping, clicking. They are in the low frequency range up to ultrasound. There is a combination of them with each other, developing into "words" and "phrases".
Dolphin's diet consists of "fish dishes", among which anchovies and sardines stand out. An interesting method of hunting is when a flock surrounds a fish school and, making a special kind of sounds, helps it to stray into a dense formation. As a result, most of it becomes the prey of dolphins. A number of facts are known, according to which dolphins helped fishermen in this way.
Reproduction and offspring
Dolphins are animals that do not have a pronounced mating season. Mates with femalesusually the leader of the pack. Pregnancy lasts about 18 weeks and is a difficult time during which the female is clumsy, moves slowly and often becomes someone's prey. One cub about half a meter long appears approximately once every two years. He is fully capable of following his mother.
Until a year and a half, cubs suck their mother's milk, they do it often and grow at a rapid pace. After that, they switch to a fish diet. Only female representatives of the flock bring up and teach little dolphins.
Common dolphins and bottlenose dolphins
Let's take a closer look at the most common dolphins. Ordinary - dolphins (a photo of the animal is given above), which are found in almost all the seas of the Northern Hemisphere: both near the coast and in open waters, it happens that they enter rivers. They have a huge number of small teeth that are conical and curved inwards. The muzzle is separated from the somewhat convex forehead by a furrow, its length is moderate. On top, the body and fins may have shades such as gray, greenish and black, the belly is white.
Skin is exceptionally smooth and shiny. In length, ordinary dolphins are up to two meters, and the height of the fin located on the back approaches 80 centimeters. The fins adjacent to the chest are about 20 centimeters wide and about 60 centimeters long.
Bottlenose dolphins - dolphins (the photo of the animal shows its appearance), which arethe most famous and popular variety. As a rule, at the mention of dolphins, an association arises with them. They are most often trained and filmed in films. Bottlenose dolphins live in the north of the Atlantic, sometimes entering the B altic. They are much rarer than ordinary dolphins, and much larger than them, in length they can reach from 3.5 to 4.5 meters.
Interesting about dolphins
You can hear a lot of interesting things about dolphins, here are some of the facts:
- In culture, the image of a dolphin has been present since ancient times. They were depicted on the coins of Ancient Greece in the 5th century BC, on ceramic products. In Africa, a stone was found that is more than two thousand years old, with animals painted on it, similar to dolphins.
- The dolphin's sharp teeth serve not to chew food, but only to capture and hold it. Since it is swallowed whole.
- From friction with water, the skin of a dolphin is subject to rapid abrasion. In order to offset this shortcoming, nature has provided for the presence of a large supply of regenerating cells. The dolphin sheds several times a day.
- Dolphins are on friendly terms with sharks. They often hunt together.
- There were so-called fighting dolphins. The military structures of the USSR and the USA trained individuals living in the ocean to perform certain combat missions.
- One of the methods of psychotherapy is dolphin therapy, based on the communication of these amazing animals and humans. With its help in childrentreat autism, hyperactivity, cerebral palsy.
- In our time, hunting for dolphins is prohibited, but despite this, their numbers are constantly declining, and some species are on the verge of extinction. Many water parks breed endangered species.
