What does a blood-engorged tick look like? - briefly
A fully fed tick expands dramatically, its body becoming rounded and balloon‑like, often changing from brown to a pale gray or whitish hue. The abdomen dominates the shape, stretching several times the length of an unfed tick and appearing soft and distended with blood.
What does a blood-engorged tick look like? - in detail
A fully fed tick exhibits dramatic enlargement compared with its unfed state. The abdomen swells to a rounded, balloon‑like shape, often exceeding the length of the head and legs combined. The dorsal surface becomes smooth and glossy, reflecting a glossy, reddish‑brown hue that darkens toward the posterior. In many species, the anterior half retains a lighter, tan coloration, while the posterior half shows a deep, almost black shade due to the concentrated blood meal.
Key visual characteristics:
- Size: Length can increase from 2‑5 mm when unfed to 10‑15 mm or more after feeding; width expands proportionally, giving a plump silhouette.
- Shape: Abdomen assumes a convex, dome‑shaped profile; the anterior capitulum (mouthparts) remains distinct and protrudes forward.
- Color: Overall coloration shifts to a dark reddish‑brown or mahogany tone; the cuticle appears semi‑transparent, allowing the blood‑filled interior to be visible.
- Texture: Surface becomes soft and pliable, lacking the hard, chitinous feel of an unfed tick. The engorged cuticle may appear slightly stretched, with fine wrinkles at the margins.
- Legs: Legs remain relatively short and tucked close to the body, giving the impression that the tick is perched on a small pedestal. They may appear splayed outward due to the enlarged abdomen.
- Mouthparts: The hypostome and palps stay extended, often visible as a dark, tapered projection from the front. The feeding tube remains anchored in the host’s skin, sometimes visible through the cuticle.
- Eyes and sensory organs: Simple eyes (ocelli) are present near the anterior margin but are often obscured by the engorged tissue; they appear as tiny dark spots if discernible.
Differences among life stages:
- Larvae: After a blood meal, larvae grow to about 1‑2 mm, appearing as tiny, translucent spheres with a faint amber tint.
- Nymphs: Engorged nymphs reach 4‑6 mm, showing a more pronounced darkening and a smoother dorsal surface.
- Adults: Adult females, the most noticeable, can expand to 12‑20 mm, displaying the full range of color and texture changes described above. Males typically remain smaller and less engorged, retaining a flatter profile.
Overall, a blood‑filled tick presents as a soft, rounded, darkened organism whose size and glossy appearance signal a recent, substantial blood intake.