Pigs have a very sensitive sense of smell and can smell and distinguish any smell. This feature plays an important role in the sexual contact between male and female pigs. The sow in estrus smells the boar, and even if the boar is not there, it will show a "standing still" reaction. At the same time, boars can keenly smell the smell of oestrus sows, and can accurately identify the position of sows even in far places, so they can be used for oestrus identification. Pigs have strong auditory discrimination, can finely distinguish the intensity, tone and rhythm of sound, and are easy to form conditioned reflex to sound stimuli such as passwords. Pigs' vision is very weak, lacking accurate discrimination, and their sight distance and visual field range are small. It can't see anything unless it is close to the object, and its ability to distinguish the shape and color of the object is poor. It belongs to high myopia and weak color.