Piloerection: Hair Standing On End In Dogs
The dog with his hair standing on end is
most probably fearful
MetPet.com Staff Writer
Piloerection, or the hair standing on end at the shoulders or from the
shoulders down the back is a sign of arousal or excitement associated most
often with fear. In addition to the bristling hair, the dog's pupils
are likely dilated, or open wide.
Although the dog looks aggressive, he is fearful and this is a sign to back
off. The more hair that is standing on end, the more nervous or
fearful. Piloerection is more visible on a dog with short, stiff hair.
A slight raising of the shoulder hairs can progress to hairs raised up and
down the back and even down the tail. Some severely frightened dogs
resemble cats with all of their hairs bristling and tails that look like
Piloerection is a function of the nervous system and is an involuntary
reaction to a stimulus such as fear or cold. Adrenalin triggers
contraction of the arrectores pilorum muscles in the skin. They
contract and push up the hair follicles causing the hair to stand away from
the body. The term comes from the Latin pilus meaning hair and
erection meaning elevated.
Similar displays occur in other animals. The Halloween cat with his
back arched and his hair bristled is one example. The idea of a bird
or a human having their 'feathers ruffled' is another.
In addition to being an involuntary reaction, piloerection has the added
advantage of making the dog look bigger. This may cause the source of
his fear: another dog, another animal or a person, to back away allowing him
When you see this in your dog, you can
calm him down so that his fear does not escalate into a snarling lunge
or even a fight. If you see this in other dogs, it is a sign to look
away and slowly back off.
Techniques to Calm Your Dog