Whale - fish or mammal? This question troubled scientists long before the advent of modern science. In particular, such a genius of thought as Aristotle tried to solve this problem. And in doing so, he came to the same opinion as our contemporaries. But let's talk about everything in order.
The whale is the most majestic inhabitant of the expanses of water. No living creature can compare with his size and grace, not to mention his amazing ability to sing songs. But what else do we know about these incredible creatures?
Who is a whale?
So, what is the meaning of the word whale? According to the dictionary, it is a large mammal that lives in the sea. That is, today, unlike the old days, finding a clue to such a confusing question is much easier. But how did it happen that an ancient descendant of whales wanted to trade land for the ocean?
Well, scientists don't know the whole truth yet. However, it is known for sure that 60 million years ago, the progenitors of all cetaceans first went to look for food back into the water. Perhaps this was prompted by a prolonged drought that destroyed part of the vegetation on the planet.or greater competition from other animals. But the fact remains that the ancestors of the whales no longer wanted to return to land.
How did a land animal adapt to life underwater?
It should be understood that such a metamorphosis did not occur in one or two years. Evolution is a chain of small changes due to which a living organism constantly mutates over thousands of years. And this ultimately produces a completely new species, radically different from its ancestors.
And yet, 60 million years later, researchers still find in the structure of the whale's skeleton echoes of those ancient times when he still walked on his four legs on land. For example, he has a hip bone that is located at the back of his body. Also, its front fins have a similar bone structure to most artiodactyls.
After a series of studies, scientists have come to a curious conclusion. It turns out that the closest relatives of cetaceans are hippos. And if you look closely, you can see some similarities in their behavior even today. In particular, their great passion for water.
Family Cetaceans
It should be noted that the whale is not the only member of its family. Dolphins and porpoises are also included in the category of marine mammals. How are they different from other inhabitants of the water depths?
- Firstly, all cetaceans are warm-blooded, unlike fish. That is why they so badly need a good fat layer,able to protect them from the cold of the underwater kingdom.
- Secondly, this family is not able to extract oxygen from water. Therefore, they must constantly float to the surface in order to replenish their supply of air in their lungs.
- Third, they all feed their children with milk. And although this process has changed a little over the years of evolution, cetaceans are still mammals.
The whole family is divided into three large subgroups:
- Baleen whales (Mysticeti) are the largest detachment of the family. Its distinguishing feature is a special filtering organ "whalebone", which is located on the upper jaw of the animal. Its main task is to filter plankton from excess impurities.
- Toothed whales (Odontoceti) are by and large predators that prey on squid and small fish. This species is able to navigate through the water using echolocation.
- Ancient whales (Archaeoceti) - unfortunately, not a single representative of this category could survive to this day.
Whales: general information
Among all the inhabitants of planet Earth, the whale is the largest mammal. On average, an adult can reach 25 meters in length. For comparison, 4 large buses take about the same amount if they are placed in one row. It is not surprising that such a colossus weighs about 90-110 tons, and some even more.
These giants live in almost all the oceans of the planet. What is true, depending on the season, they can migrate from one place to another. Similarbehavior is due to the fact that whales are sensitive to water temperature, and therefore they spend the winter closer to the tropics.
In general, among all representatives of this family, two special subspecies can be distinguished: blue and gray whales. By and large, this division is due to the skin color of these animals, but there are other equally important differences.
Echoes of the past
The gray whale is the most ancient representative of this family. Scientists have found the remains of these animals, which, according to rough analyzes, were about 30 million years old. Previously, these giants lived in almost all corners of the globe, but now they can only be found in the northern part of the Pacific Ocean.
These creatures are used to living in small groups, about 2-3 individuals in each. Although it is often possible to meet a lone whale proudly plowing the expanses of water. Yet most giants prefer to live in a group. By and large, this is due to the fact that gray whales have very strong family ties.
Perhaps it was this connection that helped them survive dangerous times. Indeed, in the middle of the 20th century, they were almost completely destroyed by whalers hunting for their fat. So, according to scientists, in 1946 the number of these mammals decreased to 250 individuals. It was only thanks to a miracle and the efforts of animal rights activists that tragedy was avoided. Now the number of these animals has increased to 30 thousand, which gave them new hope for a better future.
The blue whale is the largestcreature on earth
As for blue whales, they are rightfully considered the largest creatures on this planet. Even such a huge animal as an elephant is not able to compete with them. Such dimensions are reminiscent of the fact that once similar giants walked all over the earth's surface. Now the blue whale is the only representative of the giant animals of antiquity.
This animal is not particularly fond of people, and therefore rarely comes close to the coast. His favorite environment is the open ocean, where he feels truly free. It moves quite slowly, only at a speed of 10-12 km / h, but in case of danger, it can triple.
Like all members of its species, the blue whale feeds on plankton. And although this animal has long since changed land to water, it still cannot stay in it all the time. That is why whales so often come to the surface, while releasing fountains of water from a special hole located on the upper body.
Whale breeding
Whales are marine animals whose numbers often declined to catastrophic levels. This is due to people hunting for their meat and fat. They are the main culprits of these tragedies, but not the only ones.
Another factor that affects the population of any species is its ability to reproduce. Now, the problem is that these creatures give birth to offspring no more than once every one or two years. And at the same time, the female gives birth to only one kitten, less often - two. At the same time, depending on the subspecies of whales, pregnancy can last from 9 to 18 months.
It's nice that a mother is always very careful about her cub. Those, in turn, grow very quickly and gain weight. So, on average, a whale can gain about 50 kg of live weight per day. Therefore, one should not be surprised that in just seven months it can grow up to 14 meters in length and weigh 20-25 tons at the same time.
And although whales reach sexual maturity at the age of 4-5 years, they become full-fledged adults only at the 14-15th year of their life.
Kit: interesting facts
Few people know that:
- Whales are the only ones besides humans that can sing. And although it was previously believed that only males have this ability, recent studies have proven otherwise. So, female whales also sing songs, especially to small cubs.
- A full stomach of a blue whale can hold up to two tons of live food. For example, average fishing boats take the same amount of catch.
- If we talk about the weight of a whale, it should be remembered that one of its tongues weighs about 3 tons. As for other organs, for example, the heart can reach 600-700 kilograms.
- Although the whale still has a hip bone, it is completely useless. What's more, it doesn't even connect to the main body of the skeleton.
