What do lice look like on rats? - briefly
Rats host small, wingless insects about 1–2 mm long, with elongated bodies, six legs, and a gray‑brown coloration, typically found in the fur near the head, tail, and ventral region. They feed on blood or skin debris and appear as tiny moving specks when the animal is examined closely.
What do lice look like on rats? - in detail
Rat lice are small, wingless insects belonging to the order Phthiraptera, most commonly represented by species of the genus Polyplax. Adults measure 1.5–3 mm in length, with a flattened, elongated body that conforms closely to the host’s fur. The dorsal surface is covered by fine, translucent to light‑brown cuticular scales, giving the insect a slightly glossy appearance. Ventral segments are less sclerotized, appearing paler and more flexible.
Key morphological features include:
- Six legs, each ending in a claw adapted for grasping hair shafts; the front pair is longer, facilitating movement through dense fur.
- Antennae composed of three short segments, often hidden beneath the head capsule.
- Compound eyes reduced to small ocelli, sometimes absent in females.
- Male genitalia visible at the posterior end; females possess a larger, rounded abdomen to accommodate egg production.
Coloration varies among species but generally ranges from pale yellow‑brown to reddish‑brown. Some species display faint lateral striping or darker pigmentation on the thorax, useful for species identification under magnification.
Life‑stage characteristics:
- Egg (nit) – Oval, 0.5 mm, firmly attached to individual hairs near the base of the skin; color transitions from white to brown as embryogenesis progresses.
- Nymph – Immature forms resemble adults but are smaller (≈1 mm) and lack fully developed genitalia; they undergo three molts before reaching maturity.
- Adult – Fully sclerotized, capable of reproduction; lifespan on the host is typically 2–3 weeks, after which females lay additional eggs.
Typical infestation sites on the rodent include the ventral abdomen, inner thighs, and around the ears, where hair density provides shelter and access to blood meals. Unlike fleas, lice remain permanently attached to the host and do not jump; locomotion relies on crawling through the hair coat.
Microscopic examination reveals the characteristic “chewing‑mouthparts” (mandibles) used to ingest skin debris and blood, distinguishing rat lice from other ectoparasites. The combination of size, flattened body, scale‑covered cuticle, and clawed legs defines the visual profile of lice infesting rats.