Head lice are tiny parasitic insects that live on the scalp. They do not live on pets or other animals. A louse (the singular form of lice) has six legs, each with a curved claw that can hold tightly onto hair. Head lice crawl easily between hairs, but they cannot fly or jump. Head lice only live on human blood and feed several times a day and they live close to the scalp to maintain their body temperature. Lice do not dig or burrow into the skin – they use their needle-like mouthparts to suck blood through the skin.