Where are ticks in winter? - briefly
In the cold months, ticks seek insulated microhabitats—leaf litter, rodent burrows, or bark crevices—where temperatures stay above freezing. They remain in a dormant diapause until warmer conditions return.
Where are ticks in winter? - in detail
During the cold months, ticks abandon the exposed vegetation where they quest for hosts and seek protected microhabitats that retain enough heat and humidity for survival. Adult females of the common species (Ixodes scapularis, Dermacentor variabilis, Ixodes ricinus) typically drop to the leaf litter, moss, or the upper layer of the soil, where temperatures remain above the lethal threshold. Juvenile stages (larvae and nymphs) behave similarly, often remaining within the same litter or moving deeper into the humus to avoid freezing.
Key factors influencing winter refuges include:
- Moisture retention: Dense leaf litter and moss maintain relative humidity above 80 %, preventing desiccation.
- Thermal buffering: Soil and organic layers moderate temperature fluctuations, keeping conditions above the critical 0 °C for most hard‑tick species.
- Shelter from wind and sun: Over‑hanging rocks, fallen logs, and low vegetation reduce exposure to wind chill and direct solar radiation, which can cause rapid temperature loss.
In regions with prolonged snow cover, ticks may become encased within the insulating snowpack. The snow acts as a thermal blanket, keeping the ground temperature a few degrees above the ambient air temperature. This phenomenon, known as “snow insulation,” allows ticks to remain active at low ambient temperatures, though metabolic activity is reduced.
Some species exhibit limited activity during mild winter spells. When temperatures rise above approximately 5 °C and humidity exceeds 70 %, ticks may climb vegetation to quest for hosts. This opportunistic behavior is observed in milder climates (e.g., the southeastern United States, parts of Western Europe) where winter temperatures are not consistently below freezing.
In extreme cold zones where temperatures regularly drop below –10 °C, ticks cannot survive in the open environment. Populations in such areas rely on microrefugia such as burrows of small mammals, crevices in rocks, or the interior of animal nests. These sites provide both thermal stability and humidity, enabling ticks to overwinter in a dormant state until favorable conditions return.
Overall, winter survival hinges on locating microhabitats that preserve moisture and buffer temperature extremes. The combination of leaf litter, soil humus, snow cover, and animal shelters constitutes the primary refuge network for ticks during the cold season.