Changes

: '''Erector muscles''' are used in [[thermoregulation]].

: When the [[Body Temperature|body temperature]] gets too low the '''erector muscles''' contract causing body hairs to stand on end. This creates a pocket of trapped air under the hairs which insulates the body.

: When the [[Body Temperature|body temperature]] gets too high the '''erector muscles''' relax causing body hairs lay flat on the [[skin]].