Ticks are small arachnids, related to spiders, that survive by feeding on the blood of animals and humans. These external parasites come in a variety of colors, which can often be a key factor in their identification. The coloration of a tick is not uniform across all species and can also change depending on its life stage and whether it has recently fed.
Common Tick Species and Their Colors
Different tick species display distinct colors and markings when they are unfed.
The Deer tick, also known as the Blacklegged tick (Ixodes scapularis), typically has a reddish-brown body with a black head, scutum (a hard shield on its back), and legs. Unfed adult females are often orange-red behind their black scutum. Males are generally smaller and uniformly dark brown to black.
The American Dog tick (Dermacentor variabilis) is larger than the Deer tick and is characterized by its dark brown body with whitish or yellowish markings. In females, these markings cover about half of the body, specifically on the scutum behind the head, while in males, the markings are more extensive, covering nearly the entire back.
The Lone Star tick (Amblyomma americanum) is reddish-brown. Adult female Lone Star ticks are easily identified by a single, iridescent white or silvery spot located in the center of their back. Male Lone Star ticks, while also reddish-brown, have more diffuse white or cream-colored markings along the outer margins of their body rather than a single spot.
The Rocky Mountain Wood tick (Dermacentor andersoni) generally appears reddish-brown to gray-brown. Its scutum, or dorsal shield, often has white or cream-colored patterns. Females may have a mostly gray scutum, and males typically exhibit mottled brown and gray patterns.
How Tick Color Changes
A tick’s color can change significantly after it has fed due to a process called engorgement. When a tick attaches to a host and consumes a blood meal, its body swells dramatically as it fills with blood. This expansion is most noticeable in the soft, flexible parts of the tick’s body (the idiosoma), while the hard scutum (dorsal shield) does not expand.
As the tick’s body distends with blood, its outer cuticle stretches and becomes thinner, often causing its color to lighten. An engorged tick may transition from its original dark brown or black to shades of gray, bluish, or even a silver or white appearance. For instance, an engorged Deer tick can turn reddish-brown or rust-colored, while an engorged American Dog tick may become gray or grayish-blue. This color change, along with increased size, can make an engorged tick resemble a small, bloated sac or a small grape.