Human Head Louse

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea (Suborder: Phthiraptera), Family: Pediculidae

Size: 2.0 mm to 3.0 mm (about the size of a sesame seed)

Human Head Louse

Natural Habitat

Exclusively found on human scalps, primarily among the hairs of the head.

Diet & Feeding

Obligate blood-feeders; they feed on human blood several times a day to survive.

Behavior Patterns

They are wingless and cannot jump or fly; they move by crawling from hair to hair. Females lay eggs (nits) and cement them to hair shafts near the scalp.

Risks & Benefits

While they do not spread disease, they cause extreme itching (pediculosis) and secondary skin infections from scratching. They are socially disruptive and highly contagious through direct head-to-head contact.

Identified on: 2/25/2026