Where does this come from, and can I check it?

Arrector pili muscles pull skin hairs upright in response to cold or emotion. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a human body fact?

Yes. It sits on the Human Body shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Goosebumps are caused by tiny hair follicle muscles contracting

Arrector pili muscles pull skin hairs upright in response to cold or emotion

Goosebumps occur when minute arrector pili muscles attached to hair follicles contract. In ancestral mammals with thick fur, this reflex trapped insulating layers of warm air or made the creature appear larger to predators, though in modern humans it is largely vestigial.

Where this comes from

Encyclopaedia Britannica

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Tags: skin, muscles, reflexes

Goosebumps are caused by tiny hair follicle muscles contracting: the short answers

Where does this come from, and can I check it?: Arrector pili muscles pull skin hairs upright in response to cold or emotion. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a human body fact?: Yes. It sits on the Human Body shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.