Pilomotor

Pilomotor

Goose bumps, also called goose flesh, goose pimples, the medical term cutis anserina, are the bumps on a person's skin at the base of body hairs which may involuntarily develop when a person is cold or experiences strong emotions such as fear, nostalgia, pleasure, euphoria, awe, admiration and sexual arousal.

The reflex of producing goose bumps is known as arasing, piloerection, or the pilomotor reflex. It occurs in many mammals besides humans; a prominent example is porcupines, which raise their quills when threatened, or sea otters when they encounter sharks or other predators.

Other creatures get goose bumps for the same reason, for example this is why a cat or dog’s hair stands on end. In cold situations, the rising hair traps air between the hairs and skin, creating insulation and warmth. In response to fear, goose bumps make an animal appear larger – hopefully scaring away the enemy.