Head lice come from other humans who already have lice. They are tiny insect parasites that live on the scalp and feed on human blood. Head lice spread mainly through direct head-to-head contact, especially among children in close physical proximity such as at schools or homes. They can also spread less commonly by sharing personal items like combs, hats, or towels that have touched an infested person's hair. Lice do not jump, fly, or survive long away from a host's scalp, so they must move directly from one person to another to continue their life cycle. Head lice have co-evolved with humans for tens of thousands of years and specifically live only on human heads.