In popular usage, it is comparing a person's reaction to a shocking event to that of a cat or dog.
Your hair (except for scalp hair) will "stand on end" but since most of the hair on a human is not as obvious as a cat's or dog's, you will most likely describe the change of the texture of the skin...you get goosebumps.
A hair is equipped with a muscle called the "erector pilus". When it contracts, the hair stands up, away from the skin. It makes cats look larger and serves as a non-verbal cue to other animals that trouble is about to happen. It also traps more air in the coat of an animal to provide more insulation when it is cold. Our hair still does it even though it serves no useful purpose.
When a dog's hair "stands on end" because of some sort of stress or threat, it is interesting to note that it is called "getting its hackles up". Hackles are the neck feathers of a bird. Birds raise their hackles to threaten, warn and court. You can also "get your hackles up" when you get angry even if you don't have feathers.
To make someone's hair stand on end is to cause them to be very frightened, the expression is derived from getting goosebumps when scared and thus having your hair stand on end.
Jubual
David
Hair standing on end.
bad hair days
Where Once They Stood ended on 1979-06-02.
Hair is a word that can either mean one hair, or just hair in particular. When you say "Hair Cut", the word "Hair" is plural. There is no need to pluralize it with an 's' on the end.
It means, "My love will never end."Or if you're saying it to someone, "My love for you will never end."
about 40 ft. long. In some places, this is said to be the height. They mean the height as if stood on end. Think about it; the height of the end hole doesn't matter.
Its a metaphor because its saying that when your hair stands on its end, its a goosebump...its not comparing using like or as (simile).
Simile
all good things always come to an end