A Dolphin is a fish or not?

Always quite difficult to pass by the Dolphin show, because where else can you see such a graceful and exciting creatures! So every year dolphinariums are open in many cities in the hope to attract more viewers. But, despite such an overwhelming popularity around the dolphins, even today, lingers the aura of mystery. And one of the mysteries: who are these amazing creatures? This fish or not?

Incredible mystery

Dolphin – it's playful inhabitant of the seas, which is found in many regions of the globe. As it lives in the water, inexperienced people used to consider him belonging to one of the species of fish. After all, how else to explain the fact that he can spend hours not float to the surface? The same conclusion their bows and the presence of fins, which are an integral attribute of all the inhabitants of the underwater Kingdom.

However, the scientists, examined the features of these creatures, came to a completely different conclusion. According to their research, Dolphin – representative of the class mammals. And the closest relatives are whales, killer whales and sea cows. But why?

Overwhelming evidence

The fact that the Dolphin – it's a mammal, according to many factors. Can not refute them, so it only remains to accept this point of view. So, that's why Dolphin-fish:

1. They Have gills, and instead named creatures use light. They are slightly different from those in terrestrial mammals, yet it is one and the same body.
2. All dolphins are warm-blooded. This feature never found in fish.
3. These cute creatures give birth to live offspring, not eggs like their underwater counterparts.
4. They feed babies with milk. That is why they belong to the mammal class.
5. And finally, examining the skeleton of a Dolphin, the researchers found ample evidence that in former times, these sea creatures walked on land.

But it turned out that they replaced the usual habitat in the water spaces? What forced them to move to a new world? What is the true story of a Dolphin? And are there any facts supporting it?

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The reasons for the change of the environment

In fact, dolphins are not the only beings, who succeeded one element to another. For example, the most famous case is when the first living organisms left the watery depths and began to explore the land. However, in this case, it happened exactly the opposite. However, history is not essential. For her what matters is why it happened.

Here, scientists, unfortunately, are unable to come to a common opinion. But most likely, the reason was the shortage of food on land because of what some had to adapt to other methods of hunting. In particular, the ancestors of all cetaceans, including dolphins, learned to catch their victims under water. This led to the fact that they became more and spend more time near the water until you moved them.

Fossil record

As for historical evidence, paleontologists have been able to create relatively accurate record of the mutations of cetaceans. Of course, it has blind spots, but they are not so large as to overshadow the whole picture.

The Most ancient representative of the cetaceans is pakicetus. His remains were found on the territory of modern Pakistan, and according to rough estimates of scientists at least 48 million years. Externally, this animal looked like a dog, but its thin legs ended in small hooves on the fingers. They lived near water, eating fish or crustaceans, and thus was able to dive into the water to catch its prey. Pakicetus led a lifestyle similar to modern seals. Now let's consider more recent ancestors of cetaceans:

• One of the next stages of the evolution of pakicetus was ambulocetus, who lived approximately 35 million years ago. This predator was very impressive size: its length was about 3-3,5 meters and the weight is supposed to fluctuate in the range of 300 kilograms. Outwardly, he looked like a crocodile and could live both in water and on land.
• Another direct descendant of pakicetus was rodhocetus. The fossil of the animal was externally similar to modern seals, but had an elongated mouth with several teeth. He also had feet on the end of which may be located in the membrane, allowing it to swim quickly under water.
• Basilosaurus – this is another potential relative of the whale. However, many scholars believe that he was probably a relative of the whale, rather than an ancestor of friendly dolphins. This is due to the fact that basilosaurus had a huge size, allowing him to hunt almost all the inhabitants of the seas.
• Dorodon – relatives of basilosaurus, who lived with him in the same period. Had a much smaller body proportions. It is noteworthy that the ancestors of the dolphins finally got rid of the unnecessary legs and got his tail fin.

Mysteries of history

About dolphins written many scientific papers and conducted a lot of research, but today there are still many mysteries related to their evolution. In particular, scientists have not yetunable to determine the order in which one species replaced the other. Still, the fact that these creatures once walked the earth, there is no doubt.

By the way, with the development of genetics into the secrets of the universe gradually began to take their positions. Recently, scientists found out some very interesting information. It turns out that hippos are distant relatives of cetaceans. Just one of the stages of evolution of dolphins went deep into the seas, and the hippos decided to stay off the coast.

Well, let's discuss other features of these mammals. Because the more we know about dolphins, the more it becomes the boundary that separates this species from the other inhabitants of seas and oceans.

Intelligence

The dolphins Playing interest and smile at anyone who looks at them. However, only few people know that such behavior is hidden a remarkable intellect, distinguish them from other animals. For example, to compete with them in wit only some species of primates that are closest to the people.

The dolphins have a complex communication system built on the gestures and sounds. Because of this, they can coordinate their movements and to hunt, like one well-oiled machine. Besides, these creatures are a fast learner, memorizing new patterns and movements with incredible speed. In particular, it is why they are so popular among circus performers and showmen.

Wonders of echolocation

Dolphins are one of the few animal species that can use sound waves in their communication. The strength of their signal is so large that their voice may fly to a distance of several kilometers. Rumor has it that in the past the military has used dolphins as undersea mine detectors, as they could find a dangerous device, even in the murky and deep waters.

The Evil nature of dolphins

People believe that these creatures are very friendly and the character they like kids. Dolphin is actually a very cruel beast. After all, he is a predator and eats everything that is inferior to it in size.

However, the most violent in his behaviour is the artificial selection of offspring. So, if the Dolphin is born weak cub, he may kill him. Not to mention the fact that there are cases, when the creatures attacked the others of his kind, fighting for territory, or simply because of personal animosity.