It is a very superstitious saying that dogs cannot see "unclean" things.

1. Dogs’ vision is not that great. They are actually the “myopia” of the animal world, because compared with human vision, dogs’ vision is only 0.3 of human vision. , and in the eyes of dogs, the world is not colorful.

2. Dogs do not distinguish through their eyes. Rather, they rely on their own sense of hearing and smell. This is one of the reasons why dogs are used as demining dogs, drug detection dogs, etc.

3. However, in a dark environment, dogs can accurately distinguish things. If they detect danger signals, they will bark loudly. These are the dogs' instinctive reactions.