Where do fleas go in winter? - briefly
Fleas retreat to insulated environments such as animal burrows, nests, or indoor habitats where they remain on hosts or in protected crevices, often entering a dormant state until temperatures rise.
Where do fleas go in winter? - in detail
Fleas remain active during the cold months by exploiting protected microhabitats where temperature and humidity stay within survivable ranges. Adult insects seek out warm-blooded hosts that shelter indoors, such as dogs, cats, rodents, or humans. When a host provides a stable temperature above 10 °C and relative humidity around 70 %, fleas can feed, reproduce, and complete their life cycle inside homes, barns, or other heated structures.
In the absence of a suitable host, fleas retreat to insulated environments that retain moisture and organic debris. Common refuges include:
- Pet bedding and carpet fibers – retain heat and provide detritus for larval development.
- Cracks in flooring, baseboards, and wall voids – protected from external temperature fluctuations.
- Rodent burrows and nests – underground chambers maintain relatively constant conditions.
- Stored hay, grain, or compost piles – high organic content supplies food for larvae.
- Attic insulation and ceiling panels – warm air rises, creating a favorable microclimate.
When ambient temperature drops below the developmental threshold (approximately 13 °C), flea eggs cease hatching, and larvae may enter a prolonged diapause. In this state, metabolism slows, and individuals can survive several months without feeding until conditions improve. Diapause is triggered by declining temperature and reduced photoperiod, ensuring that the population reactivates when spring arrives.
Adult fleas that cannot locate a host will often remain in the sheltering sites mentioned above, awaiting the return of a warm-blooded animal. Their survival depends on the presence of organic matter for larvae and a protected niche that prevents desiccation. Consequently, flea infestations tend to shift from outdoor environments to indoor settings during winter, concentrating in areas where hosts congregate and where insulation offers a stable microclimate.