Dolphins are mammals that belong to the order Cetaceans and live in water. They are very similar in appearance to fish, but they are not fish. There are quite a few species of dolphins. Each species of dolphin differs more in external features than in its way of life. In total, there are about 40 species of dolphins. There are also river dolphins.
Dolphins are famous for their high level of intelligence and good attitude towards people. There are many cases when dolphins saved human lives. They also help treat psychological diseases. Very intelligent and kind animals of our planet.
Family: Dolphinidae
Class: Mammals
Order: Cetaceans
Type: Chordata
Kingdom: Animals
Domain: Eukaryotes
Anatomy of a dolphin
The common dolphin reaches a length of approximately 2 meters. Both jaws consist of 100-200 conical teeth. On the back there is a dorsal fin approximately 70-80 cm high, as well as pectoral fins about 50-60 cm long. Depending on its species, a dolphin can weigh from 40 kg to 3 tons.
The most common and famous species of dolphin that everyone knows is called the Bottlenose Dolphin. Slightly larger in size. The length of the bottlenose dolphin reaches 3.5 - 4.5 meters.
Dolphins have a small, pointed head and an elongated body. They are very dexterous and strong. They are predators by nature. Some species of dolphins have an elongated mouth like a beak. Dolphins have quite large brains. It is larger than the human brain. Also, there are twice as many convolutions as in humans. Dolphins are very smart animals.
The pink dolphin has a beak-shaped mouth:
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Dolphin lifestyle
Dolphins are social animals. A distinctive feature of dolphins is the fact that they do not fight with each other, but coexist peacefully. They move through the water in groups of several tens to several thousand individuals. They have their own language of communication, which includes about 14,000 signals.
The signals are emitted at ultrasonic frequencies that the human ear cannot distinguish. Signals are divided into echolocation (for exploring the area) and chirping (communication with each other, expression of one’s emotions). The sounds of dolphins are similar to chirping, clicking or whistling. Scientists have proven that dolphins communicate with each other in their own language. They even have full sentences in their speech! Scientists suggest that dolphins are able to assign and recognize each other's names. Dolphins also have compassion for the weaker, and are ready to help the wounded or newborns, pushing them to the surface.
A dolphin can stay underwater for a long time. However, periodically he needs to rise to the surface and inhale air. Perhaps that is why they have another feature. During sleep, only one half of their brain turns off alternately. At this time, they seem to hover under water and only periodically rise to the surface to inhale air. While one half of the brain is resting, the other half is working. There is no clearly limited interval between breaths of air, but such an interval does not exceed 30 minutes. They are not able to survive outside the aquatic habitat. They can jump out of the water to a height of up to 6 meters.
Dolphins move quite quickly in the water. Their speed can reach up to 50 km/h. Dolphins' skin quickly wears off due to friction between their skin and water. Therefore, a dolphin is capable of molting up to 25 times per day. They have a very large supply of regenerating cells.
Scientists have also proven that dolphins are able to treat mental illness in children, and these methods are now widespread in the treatment of children. Dolphins spend a lot of their time playing. They engage in sexual intercourse not only at a certain biological time, but also simply for pleasure, which distinguishes them from other representatives of mammals. They are easy to train.
Habitat
Bottlenose dolphins live in the waters of the World Ocean, here are just a few places where you can meet them:
- Greenland;
- Norway;
- Uruguay;
- Argentina;
- South Africa;
- Baltic, Black, Mediterranean, Caribbean seas;
- Gulf of Mexico;
The exact size of the dolphin population is not known for certain, but there is data on individual groups:
- At least 7,000 thousand individuals live in the Black Sea;
- The Mediterranean Sea is home to 10,000 thousand individuals;
- There are more than 65,000 thousand individuals in the Gulf of Mexico;
- There are about 12,000 thousand individuals on the North Atlantic coast of America;
- In the Pacific Ocean, together with the waters of Japan, there are about 38,000 thousand individuals or more;
What do dolphins eat?
Representatives of dolphins are predators. Their favorite food is fish, crustaceans, and mollusks. An interesting fact is the way they hunt fish. With special sounds, dolphins force fish to gather in a dense group, most of which become their prey. Friendship between dolphins and sharks has also been observed. They can hunt fish together without the shark attacking the dolphins.
Fresh water inhabitants
Of the forty species of dolphins, five live in rivers. All of them are rare animals listed in the Red Book. They differ from marine ones by their mobile neck, longer beak and low speed of movement. They feed mainly on what they find in the mud - crustaceans, mollusks, and fish hidden at the bottom. They lead a secretive, nocturnal lifestyle.
The Amazonian inia is renowned for its resourcefulness and is known for its tendency to steal fish from nets. She also catches river turtles and crabs. How a dolphin gets meat from under its shell is unknown. Most likely, it smashes its prey against rocks (in a similar way, the bottlenose dolphin kills cuttlefish). The Gangetic dolphin, also known as susuk, hunts in the muddy waters of Indian rivers. Sight is useless here, so the susuk is almost blind. But on the other hand, he masters echolocation with pinpoint accuracy - he finds any object that has fallen into the water, even a coin thrown far away.
Amazonian Inia
Dolphin breeding
Dolphins give birth to their young on the surface of the water. The gestation period for a female lasts from 10 to 18 months. During childbirth, other dolphins protect the laboring mother from shark attacks. After birth, a newborn dolphin reaches approximately 50 cm in length. A dolphin is born tail first. After birth, the mother immediately lifts the newborn baby into the air so that the dolphin takes its first breath of air. For about three years, the mother stays next to the child. Moreover, in the first year of life, the baby dolphin feeds on its mother’s milk.
Scientific studies have shown that in the first month a newborn dolphin does not sleep. In the first months, the mother dolphin constantly protects her child and is also forced to not sleep for the first month of her child’s life. The dolphin reaches sexual maturity at the age of 3 years. The approximate lifespan of dolphins, according to scientists, is 20-30 years.
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Our wet friends
Dolphins willingly make contact with humans and even perform various actions at his request. There is plenty of evidence that they saved people on the high seas, helping them get to shore.
Today, the use of dolphins in the rehabilitation of sick people is becoming increasingly popular.
Dolphin therapy has already been recognized by many medical societies and is indicated for a very wide range of diseases. If this message was useful to you, I would be glad to see you in the VKontakte group. Also, thank you if you click on one of the “like” buttons:
Whales
The body of whales is hairless (a few bristles remain only on the face), smooth, with a very thick subcutaneous layer of fat, which serves as a heat insulator. In sperm whales, humpback whales and minke whales, its thickness is on average up to 18 centimeters, and in right whales - up to 50 centimeters! Whales have no sense of smell and vision is relatively poor, but their hearing is excellent. These animals signal to each other, navigate their way and find prey using ultrasounds.
Female whales almost always give birth to one calf—twins and triplets are very rare. With the help of special muscle contractions, the female injects very nutritious milk into the baby’s mouth: it contains no more than 50% water. On excellent milk, newborn whales grow very quickly. A blue whale calf, for example, gains an average of 100 kg in weight and almost 4 centimeters in length every day in the first 7 months of life!
(And during breastfeeding, the female loses a good 30 tons—a quarter of her weight.)
Baleen whales are named so for an extremely useful “acquisition” in their life: whalebone - horny plates with fringe along the entire inner edge, facing the mouth. The height of the baleen plates varies among different species: from 25 cm in minke whales to 4.5 m in right whales. And in total there are up to 800 such plates in one whale.
Us is an excellent strainer! Having collected sea water with crustaceans, small fish and squid into its mouth, the whale closes its mouth, lifts the bottom of its mouth and tongue and pushes the water back into the sea, driving it between the plates of its strainer. The water flows out, and all the small living creatures remain in the mouth, on the fringe of the mustache. The whale swallows this live porridge. “A grazing fin whale with its mouth open,” writes Jacques-Yves Cousteau, “is one of the most menacing and majestic sights that a scuba diver sees in the sea.” An adult fin whale consumes up to 1.5 tons of plankton per day, and a young growing one consumes all 3.5 tons.
The suborder of baleen whales has three families: smooth whales, minke whales and gray whales. Valena, or the smooth bowhead whale, is that “miracle fish-whale” about which fairy tales and legends are told, about which the father of zoology, the ancient Greek scientist Aristotle, wrote, considering it not a beast, but only a fish, although it feeds its children milk and endowed not with gills, but with lungs. Only in 1693 did the Englishman John Ray prove that the whale was not a fish, but a beast.
Humpback whale
That stylized image of a whale that we usually see in illustrations to fairy tales is copied more or less exactly from Greenlandic. He, like other right whales, has no folds on the throat and belly, and no dorsal fin. The head is huge - a third of the entire length of the whale.
The length of the whale is up to 18-22 m, weight - up to 100 tons. Its homeland is the Arctic, a zone of drifting polar ice. Now the bowhead whale is protected by an international agreement; only the indigenous residents of Chukotka and Alaska are allowed to kill it. Over five centuries of whaling (it began in the 15th century), only a few of these whales have survived.
There are six species in the minke whale family. Five of them are the vomit, or blue whale, fin whale
,
sei whale
,
Bryde's minke whale
and minke whale - to an observer from the outside they look like copies of each other reduced in order of listing.
Blue whale
Blue whale
- the largest animal in the world. Its average length is about 24 m, but in 1909 one blue whale was measured, which had a length of 33 m 58 cm and weighed over 200 tons. This means that one such whale would balance 50 elephants or 250 fattened bulls, or a regiment of soldiers with full gear or 2300 civilians. The tongue of a vomit weighs 4 tons - like a large elephant! - and a newborn 7-meter whale weighs 2 tons!
The toothed whale sperm whale is an extraordinary animal. And among whales, and among other creatures on Earth. He has many rare qualities. He is the owner of many records, so to speak, on a planetary scale. For example, the sperm whale is the largest toothed creature in nature - up to 25.6 m long. There is something unusual in almost every detail of the structure of this whale’s body. Let us list point by point some of the rare and largely mysterious properties of the sperm whale:
1. Diving records (absolute, of course). 2. Battles with octopuses (giant). 3. Swallowing people (whole, without chewing). 4. Spermaceti. 5. Amber (what is it?).
A person with scuba gear can dive 300 m into the abyss of water without much harm. And what about the sperm whale? Cases of sperm whale diving lasting 1 hour 52 minutes are described, before which the whale took 60-70 deep breaths. But how far does the sperm whale go into the depths of the sea?
Emergency ships have already recovered broken telegraph cables from the ocean floor more than 14 times with... sperm whales stuck in them, as if in a snare. Perhaps sperm whales in trouble mistook the cable for the tentacles of an octopus. Grabbing it with its teeth and trying to pull the soft-bodied but not weak enemy out of its hiding place in the underwater rocks, the sperm whale became entangled in the loops of a thick wire. And unable to free himself from the snares, he died by choking.
In 1955, such a misfortune happened to one sperm whale at a depth of 1134 meters! Let's say more: deep-sea sharks living at depths of over 3 km were found in the stomachs of sperm whales. The diving depth of the sperm whale, according to scientists, is limited not by the pressure of sea water, but rather by the lack of time between breaths. Moreover, the larger the animal, the better it dives.
bowhead whale
The question arises: why does the sperm whale dive so deep? Isn’t there enough prey at the surface? No, not a little, even more than at depth. But there are more hunters for this prey here - various whales, dolphins, killer whales, sharks, other fish and birds, and a lot of them! Diving deeper and hunting for squid and fish, the sperm whale is essentially out of competition here.
The sperm whale meets only one worthy opponent in the darkness of the ocean abyss.
Here is what the American Frank Bullen, a former sailor on a whaling ship and later a writer, writes about this enemy of the sperm whale:
“A very large sperm whale was locked in mortal combat with a squid almost as large as itself. It seemed that the squid's tentacles had entangled the entire body of a giant whale... Next to the black column-like head of the sperm whale, the head of the octopus looked like such a terrible object that you would not always see even in a nightmare... The huge bulging eyes of the octopus looked at the deathly pale background of its body the gaze of a monstrous ghost."
Sperm whale
This octopus, a giant squid, is a cephalopod (a distant relative of snails, the closest relative is cuttlefish and octopuses). In the world of invertebrate animals, there is nothing larger than giant squids: some have 10-meter tentacles and weigh a ton. The battles between octopuses and sperm whales, which few have seen, are the most grandiose battles in nature. After all, the sperm whale is an excellent giant: it is born 4 meters tall and grows quickly.
20-meter sperm whales used to be quite common, but now the largest ones are 18 m long. Even the parasitic worm that lives in the placenta of a female sperm whale is 8 m long. Some old sperm whales weigh 100 tons (more precisely, they weighed, now there are no such ). The narrow 3-4-meter lower jaw of the sperm whale is armed with fifty massive teeth, twenty centimeters long and weighing a kilogram, and others - even 3 kilograms!
...1820: an enraged sperm whale rammed the whaling ship Essex twice and sank it along with its crew. Small wooden ships, on which sperm whales were previously hunted, comparable in tonnage to a whale, often died, pierced by the heads of gigantic animals. It was a difficult and dangerous job. Sperm whales rammed ships and sailors drowned.
Dr. Gudger, a tireless researcher of various oddities in nature, found old descriptions of the incredible incident of James Bartley, a whaler from the schooner "Eastern Star". The sperm whale crashed the boat and swallowed Bartley. Later, when the whale was killed and began to be cut up, they saw an unfortunate sailor in its stomach. He came to his senses and survived. Only his skin seemed to have lost its pigments: it became too white. From this dubious incident, let us now move on to things that are quite real.
“And he praised spermaceti to me
as the best medicine for shell shock.”
(William Shakespeare)
There is up to 11 tons of this spermaceti in the body of large sperm whales. It is still a good remedy for healing all kinds of wounds and abrasions, burns and eczema. Spermaceti is placed in the sperm whale's head - in a huge sac on its forehead.
It is a fat-like transparent liquid that hardens in air to form a soft white mass similar to wax. Why the sperm whale needs so much of this “fat” is not entirely clear. According to one version, it serves for echolocation (see article “Sense Organs”), according to another, it is also something like a swim bladder.
Sperm whale
The intestine is a very prosaic organ. But in the sperm whale, in addition to substances required by the laws of nature, it often contains something mysterious - precious ambergris. The word that denotes it sounds exotic and fabulous. And ambergris was once valued at its weight in pure gold, as a remedy for many ailments and a magnificent elixir of life. Ambra was used to treat epilepsy, runny nose, rabies, heart disease, it was added to censers for aroma and even to wine.
Over the past decades, the price of ambergris has decreased, but still, depending on demand and production, one kilogram of it costs from 100 to 1000 dollars. For more detailed information, let’s turn to the famous whale expert Professor Tomilin. “Some scientists take ambergris as a pathological product of the gall bladder of a sick sperm whale, others - for the normal secretion of the glands of the rectum of healthy animals, others consider it a protective formation of the intestines after irritation by parasites or the chitinous beaks of cephalopods...
Initially, it smells like earth, but after lying in a sealed container, it acquires the smell of musk or jasmine. It is highly valued in perfumery as the best fixative of floral aromas. They say that a handkerchief soaked in amber perfume smells for years... The largest pieces of ambergris ever discovered in these whales reached 420 kg."
Sperm whales swim in all oceans except the Arctic Ocean. But in summer they migrate from the subtropics and tropics to the waters of temperate and cold zones. Sperm whales and humpback whales are the only whales that have been tagged to occasionally cross the equator in their annual migrations.
Male sperm whales live in small herds most of the year, and some live alone. Females with calves and young whales, often accompanied by an old male, separately, in their own company. Sperm whales are friendly and help a comrade in trouble, wounded or sick, surround him, protect him and, if he is drowning, swim up from below, push him to the surface.
From May to October, mainly in July - August, sperm whales give birth to one, very rarely two 4-meter calves weighing more than a ton. They are fed milk for 10-11 months. Newborns grow quickly: at 4-6 years old, young sperm whales are already sexually mature.
