Quick answer
Key facts about blacklegged tick — size, diet, habitat, and conservation in one place.
Three-host life cycle
Blacklegged ticks feed once at each life stage — larva, nymph, and adult — dropping off between hosts to moult. White-tailed deer are critical adult hosts that distribute ticks, while mice and birds infect nymphs with Lyme bacteria during larval and nymphal feeds.
Questing behaviour
Ticks climb vegetation and extend front legs to latch onto passing hosts — a behaviour called questing. They detect carbon dioxide, heat, and vibration. Permethrin-treated clothing and DEET repellents reduce attachment during hiking.
Lyme disease transmission
Ixodes scapularis is the primary vector of Borrelia burgdorferi, the bacterium causing Lyme disease in the United States. Nymphs — active in late spring and summer — cause most human infections because they are small and easily overlooked. Prompt tick removal within 24–36 hours reduces transmission risk.
Expanding range
Climate warming and reforestation expand tick range northward and into Canada. Not Evaluated by IUCN, blacklegged ticks are a major public health concern rather than a conservation species. Landscape management and deer control can reduce local abundance.