Lice Lice are wingless insects that are external parasites on mammals and birds. Lice depend completely on their host for food, warmth and moisture, and cannot survive for long on their own. The head louse has three stages of growth - egg, nymph and adult. Eggs are also referred to as nits and are glued to the hair shaft by the female. Nits hatch after approximately one week as nymphs which will molt into an adult in around two weeks.
Adults live approximately four weeks and are most active at night.
They are not known to carry any diseases. Because head lice cannot live for long without human contact, it is not recommended that rooms or furniture be treated with insecticides.