The puffer fish can't be counted by the number of times it drums. The skin of the puffer fish's abdomen is looser than that of its back, and it has long spines. When it meets the enemy, it quickly rushes to the surface of the water, opens its mouth wide and inhales vigorously, its intestines in front of the lower part of the air sacs connected to the stomach are filled with gas, the abdomen swells up with it, and the spines stand up, so that the enemy does not have a place to go down and has to give up.

It can be seen that the puffer fish's belly expansion is its means of self-defense. When people catch the pufferfish on shore, they always see its belly swell up like a balloon, and some of the spiny pufferfish look like a hedgehog. The creatures each use different methods to protect themselves from being eaten or harmed by other creatures.

The meat of the pufferfish is very tasty, yet it is known to be poisonous. Pufferfish store a highly toxic poison called tetrodotoxin in their bodies. When the pufferfish meets an enemy, it will secrete a lot of tetrodotoxin from its skin, so that the enemy will immediately let go of it and dare not to eat it.

Expanded Information:

The puffer fish's stomach bulges up because it is angry or in danger. The pufferfish's body swells because the esophagus at the front of its intestines is a large, elastic bag that inflates and expands, and its abdominal skin is loose enough to expand with the esophagus.

When the pufferfish encounters danger, it quickly rushes to the surface of the water and opens its mouth to suck in a large amount of air. When the air enters the esophagus, the pufferfish rapidly expands. The inflated pufferfish floats on the surface of the water like a balloon, and the enemy often leaves due to a "misunderstanding", so the pufferfish is able to escape.

The pufferfish's stomach swells up because it is angry or in danger. The pufferfish's body expands because the esophagus at the front of its intestines is a large, elastic bag that can be inflated, and its abdominal skin is loose enough to expand as the esophagus expands.

Baidu Encyclopedia-Pufferfish