Goose bumps are tiny bumps on the skin that appear as a result of cold, shock or emotion. The bumps are formed by an involuntary contraction of the muscles under the hairs of the skin, which causes body hair to stand up on each bump.
The phrase "goose bumps" was derived from the look of a goose’s skin after its feathers have been plucked. Other words for the bumps include goose pimples, goose flesh and the medical term cutis anserina. The reflex of producing goose bumps is known as arasing or piloerection. Other animals also get goose bumps to raise their hairs, which helps to insulate them from the cold or to appear larger to enemies.