What do ticks look like and what size are they? - briefly
Ticks are tiny arachnids with a flattened, oval body and eight legs; unfed individuals measure roughly 1 mm, while engorged females can reach 5–10 mm in length. Males remain closer to the smaller size even after feeding.
What do ticks look like and what size are they? - in detail
Ticks are small arachnids belonging to the order Ixodida. Their bodies consist of two main sections: the anterior capitulum, which houses the mouthparts, and the posterior idiosoma, which contains the legs, digestive organs, and reproductive structures. The capitulum is typically visible as a short, forward‑projecting structure with a pair of chelicerae and a hypostome equipped with barbs for anchoring to host tissue. The idiosoma is covered by a smooth or slightly textured cuticle that may appear reddish, brown, or gray, depending on species, engorgement level, and feeding stage.
Size varies markedly among species and developmental stages. Unfed larvae, often called seed ticks, measure approximately 0.5 mm in length and 0.3 mm in width. Nymphs, after their first molt, range from 1.0 mm to 2.5 mm long. Adult females, when unfed, are about 2.5 mm to 4 mm in length but can expand to 10 mm–12 mm after a full blood meal, becoming markedly distended and spherical. Adult males remain relatively small, typically 2 mm–3 mm long, and do not engorge to the same extent as females.
Key visual characteristics useful for identification include:
- Body shape: Oval when unfed, becoming rounder and balloon‑like when engorged.
- Leg count: Eight legs in all stages except larvae, which have six.
- Coloration: Light brown to reddish in unfed stages; darkening to deep red or black after feeding.
- Scutum: A hard dorsal shield present in males and partially in females; absent in engorged females, exposing a soft, expandable surface.
These traits allow reliable recognition of ticks in the field and support accurate assessment of potential disease vectors.