Big and kind whales and dolphins: 10 interesting facts about these amazing animals

First, with the question of just what kinds of whales and dolphins exist on our planet, we turned to scientific classification. It divides whales into three orders: baleen, toothed and ancient. The last group is extinct. In all, there are 86 species of cetaceans on the planet.

The smallest is Hector's dolphin, which lives off the coast of New Zealand, whose length is 1.4 meters. And the answer to the question of which whale is the largest is surely known even by children: it is the blue whale – at a length of 33 meters, the animal's weight exceeds 150 tons.

World Whale and Dolphin Day is celebrated on July 23, because on this day in 1982 the commercial hunting of whales was banned. Especially for this day, we have gathered interesting facts about dolphins and whales.

1. The ancestors of whales and dolphins had hooves

The representatives of cetaceans, which include whales, dolphins and porpoises (just do not confuse them with guinea pigs – that is something else entirely) are direct descendants of land mammals of the order of artiodactyls (even-toed ungulates). In some dolphin species, shortly after birth, lanugo appears on the body – a primary hair covering, which then disappears.

A close relative of whales is the hippopotamus. Scientists assert that both whales and hippopotamuses descended from a common ancestor that lived on the planet 54 million years ago. And whales transitioned to an aquatic way of life a little later, fifty million years ago. What caused this is not reliably known to science.

2. They communicate with one another

Dolphins and porpoises are social animals; they live in groups and are able to communicate with one another. Moreover, their language of communication is complex: it consists of squeaks, whistles, clicks, squeals and other characteristic sounds, which their kin can hear underwater from many kilometers away.

Scientists have noted that when meeting other groups of their kind, a dolphin makes repeated specific sounds – scientists call this «vocal labeling», and it indicates that each dolphin has a name. Scientists also believe that these animals pass messages to one another by slapping the water with their tails or bodies. A dolphin – what other animal has its own language? True, scientists have so far been unable to decipher the language of these mammals.

3. Dolphins and whales can «see» using sound

Echolocation helps the animals in this. Dolphins make characteristic clicks in the high-frequency range, the sound is reflected off fish or other objects underwater, and a picture of what was «seen» arises in the dolphin's brain. Moreover, the dolphins' sonar is so precise that it allows them not only to see the object underwater itself, but also to distinguish what material it is made of.

Whales also have sonar «on board», which helps them determine the location of other members of their kind or find schools of fish for food.

4. Whales and dolphins do not breathe underwater

This is indeed so, since these animals are mammals and instead of gills they breathe with lungs, so from time to time they have to surface for a fresh portion of oxygen. But a reasonable question arises: how then do they sleep? And do they sleep at all, if every 5-7 minutes these animals are forced to surface and take a breath? They do sleep, but it is impossible to determine by visual observation that a dolphin is sleeping. Scientists were able to find this out after diagnosing the electrical impulses of the animals' brains using an electroencephalogram.

Dolphins, as it turned out, sleep with only half of the brain – either the right or the left hemisphere of the brain rests in turn. One half of the brain sleeps – and this is visible from one closed eye, while the other stays awake, monitoring the surroundings and controlling the moment when it is time to surface and take a breath. After an hour and a half to two hours, it comes time for the other half of the brain to «go on duty».

Curiously, cetacean calves cannot sleep: they have no phase of deep sleep, so they doze on the move. Because they have no subcutaneous fat, they cannot stay near the surface of the water without movement, so the calves have to move constantly so as not to sink.

5. Whales and dolphins are inventive hunters

Scientists never cease to be amazed at the ingenuity of whales and dolphins in how these animals obtain their food.

• The orca is not for nothing called a killer whale (although it actually belongs to the class of dolphins), since it really is a professional killer in the animal kingdom. On the internet there are quite a few videos in which orcas are filmed hunting seals trying to save themselves on an ice floe. If the ice floe is small in size, the orcas press down on its edge and flip it over. But if the floe is massive, then several orcas pick up speed and create a strong wave, which either splits the islet that is the seal's salvation or washes the prey into the water.
• Humpback whales use «bubble nets» to hunt herring schools. The whale dives beneath the school of fish and begins, circling around the school, to release air in portions. The fish, avoiding the bubbles, crowd together more and more tightly. Then all that remains for the whale is, with its mouth open wide, to surge sharply to the surface, swallowing the catch.
• Bottlenose dolphins hunt collectively in various ways. Having found a school of fish, the bottlenose dolphins begin to circle around it at speed, creating a whirlpool, and then pushing it together with the fish onto the shallows that form during low tide. Then the dolphins crawl along the shallows on their sides and eat the fish. There is also a known method of hunting by bottlenose dolphins that is called the «mud ring». First, as in the previous method, the discovered school of fish is driven more tightly together. Then the bottlenose dolphins split into two groups: one stands watch near the surface, while the other whips up silt from the bottom with their tails. The fish, perceiving the muddy water as a barrier, leap out of the water, where the dolphins on duty near the surface catch them in mid-air.

6. Dolphins do not chew fish and come in different colors

Among the interesting facts about dolphins is this one – despite having teeth, they do not chew their prey but swallow it. And carefully at that – they swallow the fish head-first, so as not to injure their throat with its spines.

It is also known that dolphins in the Gulf of Mexico carefully bite off the heads of catfish, which have cheek spines. And dolphins that feed on octopuses thoroughly soften the tentacles so as not to choke on the suckers.

Another interesting point – what color can a dolphin be? More often gray, but black, black-and-white, white-bellied, spotted and even pink ones are also found. The answer to the question «what shapes do dolphins come in» is also not so clear-cut, since in different corners of the planet there are humpbacked, short-headed, snub-nosed and large-foreheaded dolphins.

7. Porpoises are the fastest

The name, of course, does not sound very euphonious, but there is a chance to show off your knowledge in company by unexpectedly answering the question «and what kinds of dolphins are there?». Yes, there are these too. Moreover, the Dall's porpoise (such are the official names of this species) is one of the fastest marine mammals on the planet; they accelerate to 55 km/h. While hunting, they leap out of the water, and they also toss fish into the air before swallowing them.

8. Whales are long-lived

Determining a whale's age by sight is not easy, but methods of determining these animals' age do nevertheless exist.

• For example, scientists have found that baleen whales have special ear stones – earplugs – that appear with age. The animal's age is determined by the number of accumulated layers.
• Sperm whales do not have such stones, but scientists have learned to determine their age by their teeth – by the number of layers of dentin. True, not all researchers consider this method to be correct.
• Another method is studying the aspartic acid in a whale's eye, as well as counting the number of layers that form in the lens of a whale's eye.

So which whale is the longest-living? It is believed that the bowhead whale lives the longest, with a lifespan reaching 200 years.

9. Whales give birth to only one calf at a time

Despite observations and many facts about whales, the reproductive process of some species has not yet been observed by scientists. After mating, the female carries the fetus for a year, after which she gives birth to one calf, and then nurses it for half a year. A blue whale calf drinks 300-400 liters of milk a day. As a rule, whales reproduce once every two years.

10. A whale does not spout a fountain of water for amusement

Although it looks as if the animal is amusing itself, this procedure has a practical meaning, and it is connected with the breathing features of these animals. As we have already indicated, a whale breathes not with gills but with lungs. A whale breathes through a blowhole, located on its back and equipped with a valve that closes off the airways so that water does not get into them. The valve works reflexively: it closes when the whale's nose submerges underwater, and opens when it surfaces. When a whale surfaces, it exhales the air it has taken in, which, being warm and moist, condenses and looks like a fountain of water or, more precisely, of vapor. By these fountains, fishermen determine what size of whale is before them and to what species it belongs.

We hope these interesting facts about whales and dolphins will help you fittingly mark Whale and Dolphin Day – the living world on our planet is amazing, and one would like it to preserve its diversity for as long as possible.