Deer ticks (Ixodes scapularis) are also known as black legged ticks. These ticks are often mistaken for brown dog ticks. Named for their propensity to feed on white-tailed deer, these ticks may also feed on other large mammals as hosts, including humans. Humans, considered accidental hosts of deer ticks, may contract Lyme disease from bites.
Deer ticks are commonly misidentified as other species of tick. Like other ticks, their bodies are flattened and they possess eight legs as adults and nymphs, but only six legs in the larval stage. Unfed adult female black legged ticks are approximately 3 – 5 millimeters (mm) long and are colored red and brown. Female ticks that are engorged with a blood meal appear darker and are about 10 mm long. Adult males are smaller than females and are uniformly brown in color. Nymphs are between 1-2 mm long (about pin-head sized) with 8 legs and larvae are less than 1 mm long (about poppy seed sized) and have only 6 legs.
The life cycle of the deer tick takes approximately two years to complete. Their development is dependent on environment and the availability of hosts. Under favorable conditions, they may be capable of developing in less than one year. The small size of the deer tick is also a factor in the prevalence of Lyme disease. Their bites are not painful, and most victims do not notice them until they have become engorged from prolonged feeding.