Goose bumps, also calle goose pimples, goose flesh, chill bumps, chicken skin, people bumps, or the medical term cutis anserina, are the bumps on a person's skin at the base of body hairs which involuntarily develop when a person is cold or experiences strong emotions such as fear or awe. The reflex of producing goose bumps is known as horripilation, piloerection, or the pilomotor reflex. It occurs not only in humans but also in many other mammals; a prominent example are porcupines which raise their quills when threatened.