Human Lice (Head, Body, or Crab Lice)

Scientific Name: Pediculus humanus or Pthirus pubis

Order & Family: Order: Psocodea (suborder Phthiraptera), Families: Pediculidae or Pthiridae

Size: 1mm - 3mm (similar to a sesame seed or smaller)

Human Lice (Head, Body, or Crab Lice)

Natural Habitat

The human body, specifically hair (head), clothing (body), or coarse pubic and body hair (crab/pubic).

Diet & Feeding

Strictly hematophagous; they feed on human blood several times a day.

Behavior Patterns

They are wingless, crawling insects that cannot jump or fly. They attach their eggs (nits) to hair shafts or clothing fibers with a glue-like substance and depend entirely on a human host for survival.

Risks & Benefits

They cause intense itching (pruritus) and social distress. While head lice do not transmit diseases, body lice can transmit typhus and trench fever. There are no ecological benefits to humans.

Identified on: 1/14/2026