Why do we get sudden chills or goosebumps at random times and when the tempeture is warm?

Goosebumps occur when people are cold or frightened; pili muscles contract and make hair stand up. Chills are the body's way of generating heat.
Updated on Wednesday, February 01 2012 at 12:22PM EST
Source: www.nlm.nih.gov
Collection: goosebumps