What does an adult tick look like when engorged with blood? - briefly
An engorged adult tick becomes dramatically expanded, taking on a balloon‑like, rounded shape that can reach several times its unfed size; its cuticle turns a pale gray‑white or reddish hue, and the body appears smooth and glossy while the legs remain visible around the perimeter. The abdomen dominates the appearance, dwarfing the head and mouthparts.
What does an adult tick look like when engorged with blood? - in detail
An adult tick that has taken a full blood meal expands dramatically in size and changes in several visible characteristics. The body, normally flat and elongated, becomes rounded and balloon‑like, often increasing in length three to five times its unfed dimensions. The dorsal surface turns a deep, glossy brown to almost black, with a smooth, shiny texture that contrasts with the matte, lighter coloration of a starved specimen. The ventral side swells equally, creating a pronounced convex shape that can be felt as a soft, pliable mass when pressed gently.
Key morphological changes include:
- Size: Length up to 10 mm and width up to 6 mm in many species; some ixodid ticks reach 12 mm when fully distended.
- Color: Darkening to a uniform mahogany or ebony hue; patterns such as scutum markings may become obscured.
- Texture: Surface becomes glossy and slightly moist due to the presence of blood beneath the cuticle.
- Legs: Appendages remain relatively short and appear retracted, giving the impression that the tick is a smooth, rounded capsule.
- Mouthparts: The hypostome remains visible as a small, protruding structure at the anterior end, often appearing paler than the engorged body.
The engorged tick also exhibits a marked increase in weight, sometimes exceeding its original mass by 100‑200 times. Internally, the midgut is filled with a liquid blood meal, causing the cuticle to stretch without rupturing. After detachment, the tick will gradually contract as it digests the blood, eventually returning to a smaller, more typical shape. The described characteristics enable reliable identification of an adult tick in its post‑feeding state.