The largest fish in the world: whales.

Fish is one of our most common animals and the most common animal in the world. Do you know what is the biggest fish in the world? What are the characteristics of the largest fish in the world? What are the main distribution ranges? Introduce it to everyone!

The largest fish in the world: whales.

Brief introduction of whales

Whales belong to Chordata phylum, Vertebrate phylum, Mammalian phylum and Euvertebrate phylum, including about 98 viviparous mammals living in oceans and rivers. There are more than 30 species in China waters. The definition of "whale" itself is vague, and cetaceans can include all cetaceans, as well as cetaceans of specific families. Cetaceans also include all dolphins. Cetaceans are mainly divided into two suborders: baleen whales and toothed whales. There are few species of baleen whales, but they are huge. At present, the smallest known species is more than 6 meters long, and the world's largest animal, the blue whale, also belongs to the baleen whale. However, the shape of toothed whales is quite different, the smallest species is only about 30cm, and the largest sperm whale is more than 20m long. Whales are not fish. Whales belong to mammals.

Morphological characteristics of whales

Cetaceans are fish-like, with a body length of1~ 30m. They have * * * skin, only a few hairs on the nose and mouth, and no sweat glands and sebaceous glands. The forelimb is fin-shaped, and the hind limb is completely degenerated, leaving only 1 pair of small bones in the body. The skin at the tail expands left and right to form a horizontal caudal fin. There is no auricle, because there is 1 layer of fat under the skin, which can keep warm, reduce the proportion of the body and be beneficial to swimming. Some species have dorsal fins. Small eyes, no transient membrane, no lacrimal gland, poor vision. There are 1 ~ 2 external nostrils, located on the top of the head, commonly known as spray holes. Although there is no auricle, the hearing is sensitive. The left and right lungs have 1 lobe. Breastfeeding in water. The stomach is divided into four chambers, and the average life span in natural environment is 50 to 100 years.

Cetaceans are completely aquatic mammals, and some mainly rely on echolocation to find food and avoid enemies. They generally feed on mollusks, fish and salamanders, and some species can also prey on seals and seals. You must take a deep breath every once in a while. Generally, it swims from high latitude cold water area to low latitude hot water area to give birth in winter, and swims back to high latitude cold water area from low latitude to prey in summer. (fortune telling)

Whale distribution range

All cetaceans live in the sea except a few that live in fresh water.

The current situation of whale population

Due to the deterioration of the environment and the mass killing of human beings, cetaceans, especially some large members, are widely killed because of their high economic value, and many cetaceans are on the verge of extinction.

The International Whaling Commission (IWC) is an international organization responsible for whaling and cetacean protection. After commercial whaling led to a sharp decline in whale population, the International Whaling Commission decided to take action to protect whales. These include a temporary ban on commercial whaling from 1986, and the establishment of Indian Ocean Whale Sanctuary in 1979 and Southern Ocean Whale Sanctuary in 1994 respectively. However, since 1986, some countries, such as Japan and Norway, have taken advantage of the loopholes in the IWC resolution and killed at least two of them.

5000 whales or dolphins.

At present, countries that kill whales include Norway, Iceland and Japan, as well as some indigenous tribes in Siberia, Alaska and northern Canada.