Dolphins belong to the class Mammalia, the order Cetaceans, the suborder Toothed Whales, the family Delphinidae, commonly known as dolphins. They are smaller whales. There are nearly 62 species, distributed in all oceans of the world.

The body length is 1.2 to 4.2 meters and the weight is 23 to 225 kilograms.

Dolphins generally have pointed mouths and about 101 sharp teeth in their upper and lower jaws. They mainly feed on small fish, squid, shrimps and crabs.

Dolphins like to live in "groups", ranging from a few to hundreds.

Dolphins are sea mammals with extraordinary abilities and intelligence.

After training, you can play table tennis, jump through fire hoops, etc.

Apart from humans, dolphins have the most developed brains among animals.

The human brain accounts for 2.1% of a person's body weight, and the dolphin's brain accounts for 1.7% of its body weight.

The dolphin's brain is composed of two parts that are completely separated. When one part is working, the other part is fully resting. Therefore, the dolphin can remain sleepless throughout its life.

Dolphins rely on echolocation to determine the distance, direction, location, shape, and even the nature of objects.

Someone did an experiment and blindfolded the dolphins and muddied the water. They could quickly and accurately catch the food thrown to them.

Dolphins not only have amazing hearing, but also superb swimming and unusual diving skills.

According to some tests, the diving record of dolphins is 300 meters deep, while humans can only dive 20 meters without wearing a diving suit.

As for its swimming speed, it is unmatched by humans.

The speed of a dolphin can reach 40 kilometers per hour, which is equivalent to the moderate speed of a torpedo boat.

Evolution of dolphins Dolphins, as well as whales and porpoises, evolved from terrestrial mammals and are believed to be species similar to the order Artiodactyla.

In the current dolphin skeleton, there are two rod-shaped bones located in the pelvis, which are considered to be vestigial hind limbs.

They returned to the sea about 50 million years ago.

See the evolution of cetaceans for details.

In the cetacean kingdom, the dolphin family, Delphinidae, has the most species. There are more than 30 known species in the world.

Although some species are named "whales", such as killer whales and false killer whales, they are actually members of the dolphin family.

Dolphins generally refer to members of the family Delphinidae of the suborder Cetacea, the toothed whale suborder, and the white-tip dolphin belongs to the family Pufferidae, and is not strictly a dolphin.

Delphinidae is the family with the most species among whales and the most familiar to people. Its members have certain differences in body shape and habits. They can be divided into several different subfamilies, and some people divide them into different families.

Most members of the family Delphinidae, including the smallest whales, are small in size and feed on fish or molluscs. Some are larger in size and can prey on other sea animals.

In terms of appearance, dolphins can be divided into those with long beaks, short beaks and those without beaks. Most have dorsal fins on their backs, while a few have no dorsal fins.

Members of the family Delphinidae are most abundant along tropical coasts, but can also be found in other sea areas, and some can reach deep into rivers.

The most famous member of the dolphin family is undoubtedly the bottlenose dolphin Tursiops truncatus, a dolphin that often performs in aquariums.

Bottlenose dolphins are widely distributed, both along the coast and in the open ocean of all major oceans. Different members have certain differences from each other. Some people divide them into several different species. Some bottlenose dolphins are larger and are the largest beaked dolphins.

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Another famous member of the dolphin family is the killer whale Orcinus orca. The killer whale is also known as the killer whale and killer whale. It is the largest species of the dolphin family and the most ferocious of all sea animals.

Orcas are as widely distributed as bottlenose dolphins and are also used for domestication performances. Different groups of orcas have different food habits. In addition to the famous groups that feed on other sea animals, there are also some groups that feed on fish and squid.

For food.

Members of the family Delphinidae that have entered freshwater life are represented by the Amazon white dolphin Sotalia fluviatilis.

The Amazon white dolphin is very small and is the smallest long-beaked dolphin. It looks like a smaller Amazon river dolphin, but it prefers open waters and does not enter flooded forests like the Amazon river dolphin.

The living habits of dolphins. Dolphins are marine animals that breathe on the surface of the water. Each breath can last for twenty or thirty minutes underwater. When people see dolphins jumping out of the water at sea, it is the dolphins breathing.

At the same time, dolphins mostly live in shallow seas and rarely swim into deep seas.

They will carry out different activities in different places. When resting or playing, they will gather in bays near beaches. When hunting, they will appear in shallow water and rocky places.

Dolphins jump out of the water. Dolphins are a kind of intelligent and intelligent animals. They do not run away from people like the timid animals in the forest, nor do they show their teeth and claws like the beasts in the deep mountains and old forests when they meet people. Dolphins always behave

They appear to be very docile and approachable, and are sometimes even friendlier to humans than dogs and horses.

We have heard many stories of dolphins rescuing people who fell into the water. We also often hear reports of dolphins playing and having fun with people. Some stories have even become sensational news.

Dolphins that have been trained can even imitate the voices of some people.

In the 1970s, three scientists in the United States allowed two dolphins to learn 25 words.

Recently, four scientists including Dr. Owens of the Pacific Ocean Foundation trained two dolphins and spent three years teaching them 700 English words.

However, some scientists believe that the "language" or "dialect" of animals cannot be described as too bizarre.

But dolphins do have unusual intelligence.

Its brain size and quality are also among the best in the animal kingdom.