Diagram: Two-Year Life Cycle of the Blacklegged Tick (Ixodes scapularis, also known as the Deer Tick or Bear Tick)
- In the spring and summer of year one, eggs hatch into larvae which feed once and molt into nymphs. Nymphs become dormant for the fall and winter.
- In year 2, nymphs feed from May through July. At this time, the nymph may transmit disease-causing organisms (such as the bacteria that cause Lyme disease) to humans or to wild or domestic mammals.
- In the fall, nymphs molt into adult male and female ticks. The females feed on deer and other large mammals, mate, lay eggs, and die. If females don't feed in the fall, they try to find a large mammal host in the following spring. Male blacklegged ticks attach to a host to wait for females, but do not take a blood meal.