Top 10 Interesting Dolphin Facts

Dolphins are mammals, they can be found in the open seas, in the mouths of rivers. They are ideal swimmers as they their body is adapted to movements in the water. The body of a dolphin is from 2 to 3,6 m, they weigh from 150 to 300 kg. They have pointed teeth, their number is a record – 272, shaped like pointed spikes. This is necessary to keep slippery prey.

Here are 10 more interesting facts about dolphins for 4th grade students that will help you learn more about these mammals. Until now, the information that we receive about them is surprising and amazing, because. Dolphins can not be compared with any animal that lives on our planet.

10 The name can be interpreted as “newborn baby”

The word “dolphin” comes from the Greek δελφίς, and it is from the Indo-European, meaning “womb», «womb“. Therefore, some experts translate it as «newborn baby“. Such a name could appear because the dolphin is somewhat similar to a child or its cry resembles the cry of a baby..

9. The brain of a dolphin weighs more than a human and has more convolutions

The weight of the brain of a dolphin is 1700 g, while the brain of an ordinary person is no more than 1400 g. The researchers found that it is striking not only in its size, but also quite complex in its structure. There are more nerve cells and convolutions in it than in humans. They differ only in form. in them it resembles a sphere, while in ours it is slightly flattened.

The associative area of ​​the cerebral cortex is the same as in humans, which may indicate a developed intellect. The parietal lobe is the same size as in humans. But a very large visual part of the brain.

They know how to sympathize with others, can, if necessary, come to the rescue. So, in India they were officially recognized as individuals, so dolphinariums that violate their rights are banned in the country.

8. Have a sound signal system

Dolphins have their own language. Psychoanalyst and neuroscientist John C. Lilly wrote about this in 1961. He said that these mammals have 60 basic signals. The researcher hoped that in 10-20 years humanity would be able to master this language and communicate with them.

They have as many organizations of sounds as a person, i.e. they compose sounds into syllables, words, and then phrases, paragraphs, etc. They have their own sign language when they take various poses, give signs with their heads, tails, and swim in different ways.

In addition There is also a spoken language. It consists of sound pulses and ultrasound, i.e. screeching, chirping, squeaking, roaring, etc. They have 32 types of whistles aloneeach one means something.

So far, 180 communication signs have been found. Now they are trying to systematize in order to compile a dictionary. Scientists are sure that the dolphin emits at least 14 thousand sound signals, but we do not hear many of them, because. they are emitted at ultrasonic frequencies. Despite the fact that work is underway in this direction, it has not been possible to completely decipher their language.

Everyone has his own name, which is given to him at birth. This is a characteristic whistle, lasting 0,9 seconds. When the computer was able to figure out these names and they were scrolled along with several captured dolphins, a single individual responded to them.

7. “Gray’s Paradox”

He is associated with dolphins. In the 1930s, James Gray found that dolphins move at tremendous speeds, at least 37 km/h. This surprised him, because. according to the laws of hydrodynamics, then they should have had muscle power 8-10 times more. Gray decided that these mammals control the streamlining of their body, their body has 8-10 times less hydrodynamic resistance..

In our country, research was carried out until 1973, the first experiments appeared that confirmed Gray’s statements. Most likely, Gray was mistaken about the speed of movement of dolphins, but they still know how to reduce the resistance to their movement, but not by 8 times, as the Englishman believed, but by 2 times.

6. Pregnancy lasts 10-18 months

Dolphins live for about 20-30 years, but their gestation period is longer than that of humans. They carry babies 10-18 months. They can be born both small, up to 50-60 cm, and larger. When a dolphin is about to give birth, it begins to move, arching its tail and back. Other dolphins surround her in a tight ring, trying to help and protect.

As soon as the baby is born, he is pushed up so that his lungs expand and he can take a sip of air. He recognizes his mother by her voice, because she starts whistling immediately after giving birth, 10 times more often than usual.

In the first few months, an adult dolphin does not leave his child, if he is hungry, the baby begins to cry, like in humans. All young mammals sleep a lot in the first months after birth. But not dolphins.

At first, the little dolphin does not know what sleep is at all, he begins to sleep only 2 months after birth. The first year of life, the baby lives next to his mother, she not only feeds him, but also educates him, punishes him if he does not obey. Then the mother begins to teach him to get food and communicate. The dolphin grows in the female herd, and the males live separately. One mother can have 7-8 cubs, or only 2-3.

5. “Fighting” dolphins in the USA and the USSR

The use of dolphins was first proposed back in the 1950th century, but this idea was only realized in the 19s. The US Navy conducted many tests in which various animals participated (more than XNUMX species). Dolphins and sea lions were selected. They were trained to find underwater mines, destroy submarines by kamikaze. But the US Navy denies they ever did anything like that. But, nevertheless, training bases exist, they have a special Marine Mammal Fleet.

The USSR established its own research center near the Black Sea in 1965, in Sevastopol. In the early 1990s, dolphins were no longer trained for military purposes. But in 2012, Ukraine continued to train, and in 2014, the Crimean fighting dolphins were taken into the service of the Russian Navy.

4. On ancient coins there are images of dolphins

From the XNUMXth century BC e. images of dolphins can be found on the coins of Ancient Greece, as well as on ceramics. In a cave in South Africa in 1969, a stone was found that is at least 2285 years old. A man and 4 marine inhabitants resembling dolphins were drawn there.

3. Dolphins only have 1 of 2 hemispheres of their brains in non-REM sleep.

Animals and humans cannot stay awake for a long time, after a while they are forced to sleep. But dolphins are designed in such a way that only one half of their brain can sleep, while the other remains alert at this time. If they did not have this feature, they could drown or become the prey of predators.

2. Dolphin therapy is a method of psychotherapy

Swimming with dolphins is useful for those who have suffered severe psychological trauma. It helps to recover. Dolphin therapy is used to treat cerebral palsy, childhood autism, Down syndrome, mental retardation, speech and hearing disorders. It also helps to cope with depressive disorders, if they are non-endogenous.

1. The dolphin family includes about 40 species

The dolphin family is a suborder of toothed whales, which includes about 40 species.. There are 11 of them in our country. These include bottlenose dolphins, killer whales, whale dolphins and many others.