Why do men always have long beards in traditional operas in China?

Add a little introduction to beards in professional books: beards are called "mouth" in the north and "mouth surface" in the south. The fake beards hung by the characters in the play. They are made of yak hair or human hair, and the colors are black, white, light, red and purple. According to the identity, personality, age and physiological characteristics of the opera characters played by the actors, the artists of the previous generation made various mouth shapes through artistic exaggeration, and created more than a dozen performances such as throwing, lifting, winding, lifting, shaking, picking, pushing, laying, reasoning, copying, tearing, blowing and twisting (mouth shapes) through the use of mouth shapes.