What does a large tick look like? - briefly
A large tick appears as a swollen, dark brown‑to‑black oval roughly the size of a pea. Its body is engorged and firm, with the front legs clearly visible.
What does a large tick look like? - in detail
A large tick measures up to 15 mm when fully engorged, far exceeding the 2–5 mm length typical of unfed specimens. The body is oval, expanding dramatically during blood intake so that the dorsal surface becomes balloon‑like and the ventral side flattens against the host’s skin. The dorsal shield (scutum) of a female loses its distinct pattern as the cuticle stretches, turning from a dark brown or reddish hue to a pale, almost translucent shade. Males retain a smaller, more rigid scutum and remain under 5 mm, but females reach the maximum size described.
Key visual markers:
- Legs: Eight sturdy, jointed legs protrude from the anterior margin; they are visibly longer than those of many other arachnids and end in claw‑like tarsi that grip the host’s hair or fur.
- Mouthparts: A short, ventrally positioned capitulum houses the hypostome and chelicerae; the hypostome appears as a barbed, pencil‑shaped structure that anchors the tick while feeding.
- Eyes: No eyes are present, a trait that distinguishes ticks from many spider species.
- Surface texture: The engorged cuticle feels smooth and slightly glossy; fine setae (hair‑like structures) are sparse, giving the tick a sleek appearance.
- Color variation: Initial reddish‑brown coloration darkens to a grayish‑white as the tick stretches; blood‑filled abdomen may display a visible, dark red core through the thin wall.
When detached from a host, a fully expanded tick retains its swollen shape for several days before the cuticle contracts during the next molt. The combination of size, rounded silhouette, elongated legs, and altered coloration provides a reliable visual profile for identifying a sizable specimen.