Human Head Louse

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea, Family: Pediculidae

Size: 2-3 mm in length (about the size of a sesame seed)

Human Head Louse

Natural Habitat

The human scalp, primarily near the neck and behind the ears, where they attach to hair follicles.

Diet & Feeding

Obligate hematophages; they feed exclusively on human blood several times a day.

Behavior Patterns

They are wingless and cannot jump; they move by crawling from hair to hair. They lay eggs (nits) which are glued strongly to the hair shaft. They cannot survive for more than 24-48 hours off a human host.

Risks & Benefits

Risks include intense itching (pruritus due to an allergic reaction to saliva) and potential secondary skin infections from scratching. They do not transmit diseases. There are no ecological benefits to humans.

Identified on: 12/27/2025