1, biological classification: dolphin is a mammal, belonging to the phylum chordata, vertebrate subphylum, mammalian, true animal subphylum, cetaceans, toothed whales, dolphin family. While the pufferfish is a fish, specifically belongs to the leatherfish leatherfish family, is a warm water marine benthic fish.
2, appearance and morphology: the dolphin's skin is smooth and hairless, the body is gray-black, the color gradually changes from dark gray near the tip of the dorsal fin to light gray, the upper and lower sides of the dorsal and caudal fins are gray-black, and the abdomen is basically pure white. The body is streamlined, thick and rounded in the middle, tapering from the back of the dorsal fin, with a pronounced bulge on the forehead. The pufferfish, on the other hand, has hairy spines all over its body, a small mouth with a rounded head, a blackish-brown back, a white belly, and eyes that are usually bluish-green and change color as the light changes. Pufferfish are larger than dolphins and can grow up to 3 meters long, and sometimes, like dolphins, they chase fish collectively to improve their feeding efficiency.
3, habits: dolphins are group-living mammals, like to live in sunny, moderate water temperature (about 20 ℃ ~ 31 ℃) of the sea, mainly distributed in tropical waters, some species will also enter the freshwater to reproduce, a few varieties will even live in fresh water. They are good at using echolocation to detect their surroundings and ensure their safety. Puffer fish, on the other hand, mostly live in the sea and some freshwater as well, and will swim from the sea to the middle and lower reaches of the Yangtze River around the Ching Ming Festival every year. Puffer fish has a special esophagus structure, and when it encounters enemies, it can inhale water and air to make its chest and abdomen swell like a ball and float on the surface of the water, so as to escape from enemies.
4. Relationship with human beings: The relationship between dolphins and human beings has a long history. As early as in ancient times, people began to hunt dolphins and use their meat as a source of food. And puffer fish, although its meat is delicious, but its liver, roe, blood, etc. are highly toxic, easy to poisoned to death after eating, so you need to be especially careful when eating.