The most important food source for pigs is plant roots, tubers and insects in the soil, so the pig's nose is used to arch the soil, and the canine teeth on the wild boar will turn out to help, so domestic pigs can only rely on the nose. First, breathe.

Second, smell the smell

Third, in ancient times, pigs were not used as livestock. Its nose is sharper than it is now, and it is used to arch (this is a survival skill) food, such as digging holes on one side of the earth arch and arch grass leaves to drink water. Nowadays, pigs often arch their pens with their noses and then run away. During World War I, it was found that pigs were not deeply affected by poisonous gas. Through research, it is found that their noses go deep into the soil and rely on the soil to filter toxic gases. So gas masks were invented, which is why people who wear old gas masks wear pig noses.