Said as 马鬃 for a horse's mane and 猪鬃 for the stiff back-and-neck bristles of a pig (a real export commodity used in brush-making). The hair radical on top tells you immediately it is about coarse animal hair.
The 'long hair' radical 髟 drapes over the top — itself a picture of streaming hair. It files the character with words for hair and fur, here the long coarse hair on an animal's neck.
