What do fleas on rats look like? - briefly
Fleas infesting rats are tiny, wingless insects about 1–3 mm long, with dark brown to reddish‑black bodies that are laterally flattened for movement through fur. Their legs end in strong claws, and they possess a short, stiff set of bristles called the genal comb.
What do fleas on rats look like? - in detail
Fleas that parasitize rats are small, laterally flattened insects ranging from 1.5 mm to 3 mm in length when unfed. Their bodies are segmented into head, thorax, and abdomen, each covered by a hard, chitinous exoskeleton that resists desiccation. The dorsal surface exhibits a dark brown to reddish‑black coloration; the ventral side is lighter, often pale brown.
The head bears a pair of well‑developed compound eyes and elongated antennae composed of 13 segments, which are tucked into grooves when the flea is at rest. Mouthparts form a piercing‑sucking stylet, adapted for penetrating the host’s skin and extracting blood. The thorax supports six jointed legs, each ending in a pair of spines that enable rapid jumping; leg segments are proportionally longer than those of many other ectoparasites, facilitating leaps of up to 100 times the flea’s body length.
The abdomen expands after feeding, becoming engorged and visibly distended. In the post‑blood‑meal state, the abdomen may appear bluish‑gray due to the ingested blood. The flea’s setae (hair‑like bristles) are sparse, mostly located on the legs and the posterior margin, providing limited sensory input.
Key morphological identifiers include:
- Size: 1.5–3 mm (unfed); up to 5 mm when engorged.
- Color: Dark brown to black dorsally; lighter ventrally.
- Shape: Laterally compressed, streamlined for movement through host fur.
- Legs: Long, spined, with specialized coxa‑trochanter joints for jumping.
- Mouthparts: Syringe‑like stylet for hematophagy.
Life‑stage variations are evident: larvae are whitish, C‑shaped, and lack legs, while pupae develop within a silken cocoon attached to the host’s nest material. Adult fleas retain the described morphology throughout their reproductive period, which can last several weeks under favorable conditions.