Louse

Scientific Name: Phthiraptera (Order)

Order & Family: Order: Phthiraptera; Families include Pediculidae (human head/body lice) and Pthiridae (crab lice)

Size: 0.5 mm to 8 mm (most human-associated species are 2–3 mm)

Louse

Natural Habitat

Exclusively parasitic on the bodies of warm-blooded hosts, including humans, mammals, and birds

Diet & Feeding

Obligate parasites that feed on host blood or skin debris and secretions

Behavior Patterns

Wingless and highly specialized for clinging to hair or feathers; they undergo incomplete metamorphosis and usually spend their entire life cycle on a single host.

Risks & Benefits

Risks: Cause intense itching (pruritus), skin irritation, and can transmit diseases such as typhus or trench fever. Benefits: None to humans; purely parasitic.

Identified on: 1/14/2026