What do fleas that bite humans look like? - briefly
Human‑biting fleas are tiny, 1–3 mm long, dark brown to reddish, laterally flattened, and equipped with powerful hind legs for jumping. They possess short antennae, lack wings, and have a hardened exoskeleton.
What do fleas that bite humans look like? - in detail
Fleas that feed on people are tiny, laterally flattened insects typically measuring 1.5–3 mm in length. Their bodies are narrow and oval, allowing them to move easily through hair or fabric. The exoskeleton is hardened, giving a dark brown to reddish‑black appearance; after a blood meal the abdomen may appear swollen and lighter in color.
Key morphological traits include:
- Head: small, invisible from a frontal view, bearing short, segmented antennae that end in a club‑shaped tip.
- Mouthparts: piercing‑sucking stylets adapted for penetrating skin and drawing blood.
- Thorax: bears six long, powerful legs ending in tiny comb‑like spines (genal and pronotal ctenidia) that anchor the flea to the host.
- Legs: capable of rapid jumps; each leg has a row of spines that provide grip on fur or clothing.
- Abdomen: segmented, expandable after feeding; covered with fine hairs that give a slightly fuzzy texture.
The most common species biting humans are the cat flea (Ctenocephalides felis) and the dog flea (Ctenocephalides canis). Both share the described size and coloration, differing only in subtle variations of genitalia and ctenidia patterns, which require microscopic examination for precise identification.
In the immature stages—egg, larva, and pupa—the insects are whitish, soft, and lack the hardened exoskeleton of adults. Larvae are slender, C‑shaped, and equipped with bristles rather than legs; they feed on organic debris rather than blood. Pupae are enclosed in silky cocoons, appearing as tiny, brownish spheres until emergence.
Overall, human‑biting fleas are minute, dark, laterally compressed insects with specialized jumping legs, comb‑like spines, and a blood‑sucking mouth apparatus. Their appearance changes markedly between the adult, blood‑engorged form and the softer, non‑blood‑feeding immature stages.