Head lice are very small insects that live on the scalp, which is also where they lay their eggs. They survive longer when on the scalp, but how long can head lice live without body contact?
Lice are commonly spread from person to person by sharing personal items such as combs, brushes, hats, helmets, scarves, clothing and headphones. Pets can be a carrier for the lice but the lice cannot survive long on an animal.
Females lay up to 400 eggs in their lifespan, which is spaced out to about eight eggs per day. These eggs hatch in one to two weeks.
Head lice begin as empty eggs called nits. They attach themselves near the root of the hair with a substance that is like glue and cannot be simply washed away. When the eggs hatch, the nymphs feed on blood from the scalp.
Nits, or lice eggs, can live for up to 10 days but will need to feed on human blood after hatching. Adult lice can live for up to one month on the head of a human but die within two to three days without body contact. The total life span of lice is 40 to 50 days, if you include the complete life cycle: egg, nymph and adult.
The term "nitpicking" comes from the tedious process of combing through someone's hair to find and remove lice and their eggs.