What does the largest tick in the world look like?

What does the largest tick in the world look like? - briefly

The biggest recorded tick reaches roughly 12 mm in length and 8 mm in width when fully engorged, showing a dark, flattened oval body with legs visible at the rear. It appears as a small, leathery disk that expands dramatically after feeding.

What does the largest tick in the world look like? - in detail

The biggest tick recorded measures roughly 12 mm in length and 8 mm in width when unfed, expanding to about 30 mm after a full blood meal. Its body is oval, dorsoventrally flattened, and covered by a leathery, reddish‑brown integument. The dorsal shield (scutum) is absent in soft‑tick species, allowing the abdomen to swell dramatically during feeding. The anterior region houses the capitulum, a compact cluster of chelicerae and a hypostome that penetrates the host’s skin. Six legs emerge from the ventral side, each ending in a pair of clawed tarsi adapted for gripping fur or feathers.

Key visual characteristics:

  • Color: uniform reddish‑brown in unfed state; deepening to dark brown or black when engorged.
  • Surface texture: smooth, with fine striations visible under magnification.
  • Leg morphology: relatively short, robust, and positioned laterally, giving the tick a low profile.
  • Mouthparts: short, stout hypostome with backward‑pointing barbs, enabling secure attachment.

When engorged, the tick’s abdomen becomes balloon‑like, stretching the cuticle to accommodate several times its original volume. The ventral side displays a glossy, slightly translucent membrane that reveals the blood meal within. In contrast, the unfed specimen retains a compact, compact silhouette suited for crawling through leaf litter and vegetation.