Goosebumps are a way for our bodies to keep heat in when we are in a cold environment, but they also serve other purposes – if you’ve ever been scared and gotten goosebumps, you’ll know the feeling.
These tiny little bumps are the muscles at the base of our hair follicles contracting to raise the hair and close the follicle. This stops heat escaping, but also protrudes the hair into the environment maybe for sensory reasons or when we used to have more body hair, to make us look bigger to a predator.
If there is no hair in the follicle, the action still exists, for example if you wax your legs or arms, you can still get goosebumps.
Some people respond to nails down a blackboard with goosebumps, when listening to evocative music, or experiencing certain positive feelings. Some people are able to get goosebumps on purpose, with the most common area to get goosebumps being the forearms, but the neck, legs and other areas of skin with hair on them react too. A classic is ‘the hair stood up on the back of my neck’ when something scary was just about to happen.
Goosebumps can also be a sign of disease, including epilepsy, brain tumours or a condition known as autonomic hyperreflexia. Drug withdrawal can also cause goosebumps.
The medical name for goosebumps is cutis anserina or horripilation (based on horror, as in, scared). We experience goosebumps only when we are cold, or have strong feelings – fear, euphoria or even during sex. We may get goosebumps when we are stressed, as part of our natural reflexes. This reflex is called piloerection (meaning a stiff hair), and occurs in many animals, not just humans. A wonderful example of an animal that acts like this is a porcupine, with quills raised when the porcupine feels threatened. A sea otter also has this reflex when it runs into a shark, and you may have noticed that even cats do this when they are scared.
Most birds, when plucked, share the same ‘goosebumps’ skin, and this word, or some other bird’s name or reference to, is used in many unrelated languages for the same phenomenon – Japanese, Hungarian, Spanish, Afrikaans.