Question

why do we shiver when we experience cold

Answer 1

we have a certain body temperature. when we feel cold our brain send messages to make ourselves warm up....as it it very less temperature than it must be and body telling your muscles to tighten and loosen really fast, which is what we call shivering. It does this because when muscles move they generate heat.

Answer 2

When you feel cold tiny sensors in the skin send messages to the brain telling it u need to be warm  then the brain sends messages to the nerves