Human head lice don’t live very long. Maybe about 40-45 days is their entire life cycle. They need human blood to survive. They feed about every 2-3 hours off the scalp of the head. If they come off the scalp, should that happen, they die within 24-48 hours. They don’t like to come off the scalp. They need high heat and high humidity to survive. They like to lay their eggs on the hair shaft very close the scalp where it is nice and warm and nice and humid. When those eggs hatch, they can immediately get on the scalp and feed on the blood. Adult females lay 80 to 90 eggs during their lifetime and their eggs take about 8 to 9 days to hatch. Infestations will continue literally for years if you don’t seek treatment so we recommend that you seek treatment and make sure you find out if you have a case of head lice or not.