Many people mistakenly believe ticks disappear in winter, ending concerns about tick-borne diseases. However, certain tick species remain active even in cold conditions. Understanding their behavior during colder months is important for continued vigilance against bites and associated health risks.
How Ticks Endure Cold
Ticks do not simply die off when temperatures drop; they employ various biological and behavioral adaptations to survive the cold. One important strategy is diapause, a dormant state similar to hibernation, where their development and activity significantly slow down. This process is often triggered by environmental cues like shortening daylight hours.
Some tick species produce cryoprotectants, natural “antifreeze” compounds like glycerol, to prevent ice crystal formation within their cells, allowing them to endure freezing temperatures. While deep freezes can be lethal, many ticks become active on days when temperatures rise above freezing, typically around 35-45°F (1-7°C), even with snow on the ground. Ticks also use microclimates, seeking insulated environments like leaf litter, tall grasses, or beneath snow cover to avoid extreme cold and maintain stable temperatures.
Key Winter Tick Species and Their Winter Haunts
The blacklegged tick (Ixodes scapularis), also known as the deer tick, is a primary concern during winter due to its activity in colder conditions and its role in transmitting Lyme disease. Adult blacklegged ticks are active in the fall and can remain so on mild winter days, actively seeking hosts when temperatures are at or above 4°C (approximately 39°F).
Their preferred winter habitats include dense leaf litter, tall grasses, brushy areas, and wooded edges, providing essential insulation and cover. Around homes, woodpiles can also serve as hiding spots for ticks. While overall activity is reduced compared to warmer seasons, adult ticks can still engage in “questing”—waiting on vegetation for a host to pass by—even on milder winter days.
Minimizing Winter Tick Encounters
Maintaining vigilance against ticks should be a year-round practice, as prevention measures remain relevant even during winter. When spending time outdoors in wooded or grassy areas, wearing long pants and long-sleeved shirts helps protect exposed skin. Opting for light-colored clothing makes it easier to spot attached ticks.
Applying EPA-registered tick repellents containing ingredients like DEET or picaridin to exposed skin provides additional protection. Permethrin-treated clothing and gear offer another layer of defense, as permethrin irritates ticks upon contact, causing them to dislodge. Around the home, clearing leaf litter and keeping grass mowed reduces potential tick habitats, even in colder months. After outdoor activities, performing thorough body checks, focusing on hidden areas, is important. Pet owners should also continue tick prevention treatments for their animals throughout the winter.