Ticks hibernate in the winter
Executive summary
Ticks do not undergo true hibernation like some mammals; instead most species enter a low‑energy or diapause state and shelter in leaf litter or on hosts, and many can become active during warm winter days when temperatures rise above species‑specific thresholds (for example ~4°C/45°F for blacklegged ticks) [1] [2] [3]. Practical consequence: cold weather reduces but does not eliminate tick risk, and geographic and species differences—plus milder winters—mean vigilance is still warranted [4] [5].
1. What “hibernation” means — and why that term misleads when applied to ticks
Biologists reserve “hibernation” for endotherms that undergo long, regulated torpor with metabolic adaptations; ticks, as arthropods, instead enter diapause or a dormancy‑like low‑energy state responsive to temperature and photoperiod, a distinction emphasized across entomology and public‑facing explanations [6] [7] [8]. Several public and pest‑industry sources note that ticks slow metabolism and seek insulated microhabitats rather than undergoing the physiological hibernation seen in bears or groundhogs [6] [5].
2. How ticks survive winter: shelter, physiological tricks and hosts
Ticks survive winter by burrowing under leaf litter, soil, bark or snow which buffers ground temperature, producing cryoprotectants and reducing body water to lower freezing risk, or by remaining attached to a warm‑blooded host that keeps them active—the winter tick is a clear example of a species that stays active year‑round on hosts [5] [9] [2]. Snow can act as an insulating blanket that stabilizes soil temperatures and actually improves overwinter survival in some regions [10].
3. Temperature thresholds and species differences determine winter activity
Not all ticks behave the same: adult blacklegged (deer) ticks can become active when temperatures climb to about 4°C (≈39°F) and are reported to quest on milder winter days even with snow on the ground, while other species retreat more deeply until prolonged warmth returns [3] [2]. Some sources claim activity resumes above ~45°F (≈7°C) or after several consecutive warmer days, highlighting variability in how studies and extension services express thresholds [5] [7] [11].
4. Geography, climate and climate change shift the winter story
Regional climate matters: in northern areas consistent below‑freezing ground conditions reduce tick activity, whereas milder, wetter winters or insulating snowpack can preserve or even favor survival, and warming winters are linked to expanded year‑round activity and larger populations the following seasons according to public health and research summaries [1] [10] [12]. The messaging from universities (e.g., Rutgers) stresses that “tick season is every season” in many places, reflecting both local observations and public‑health caution [4].
5. Practical implications and why some outlets emphasize year‑round risk
Pest control and veterinary blogs frequently stress that “ticks don’t hibernate” to encourage ongoing prevention—an implicit agenda to sell year‑round control or products—yet that emphasis rests on real biological facts: dormancy is not absolute and some species feed in winter or re‑emerge on warm spells [2] [13]. Public health guidance from research and university sources focuses on behaviorally useful thresholds and prevention rather than alarmism, noting that risk drops but is not eliminated with cold [4] [3].
6. Bottom line and limits of this roundup
Ticks are not true hibernators; they survive winter through dormancy/diapause, microhabitat sheltering, physiological antifreezes, or by remaining on hosts, and many species will become active during warm winter intervals—local climate and species determine actual risk [6] [5] [9]. Reporting here synthesizes extension, pest‑control and university sources; claims about exact temperature cutoffs vary across those sources and across species, and this review does not substitute for region‑specific entomological or public‑health advisories if precise local guidance is needed [2] [3].