When colder months arrive, spiders often seem to vanish from sight. They don’t disappear but employ various strategies to survive the drop in temperature and scarcity of food. These adaptations allow them to endure harsh conditions until warmer weather returns. The specific tactics used vary depending on the spider species and their environment.
Spider Survival Strategies
Spiders are cold-blooded, so their body temperature depends on their surroundings. As temperatures decrease, their metabolic rate slows significantly, leading to reduced activity. Many species enter diapause, a state of suspended development or reduced metabolic activity similar to hibernation. This state helps spiders conserve energy when food sources become scarce.
To withstand freezing temperatures, some spiders produce antifreeze-like compounds in their body fluids. These compounds lower the freezing point of their cells, preventing ice crystals from forming internally and causing damage. While in diapause, spiders become sluggish and seek sheltered spaces, though some may become active on warmer days to hunt for prey.
Outdoor Winter Shelters
Many spiders shelter outdoors during winter, seeking protected spots. They find refuge under natural elements like rocks, logs, and leaf litter, which provide insulation and protection from extreme cold and predators. Loose bark on trees and cracks or crevices in outdoor structures also offer suitable hiding places. These locations minimize exposure to wind and fluctuating temperatures.
Some spiders burrow into the ground or find shelter in the subnivean zone, a cave-like space that forms between the soil and the snow surface. This area offers consistent temperatures that remain above freezing, providing a relatively stable environment. Certain species may also construct small, silk-lined pods or sacs in sheltered spots like chimneys or downspouts, creating insulated retreats to weather the cold.
Indoor Winter Retreats
While many spiders overwinter outdoors, some find their way into human dwellings as temperatures drop. Spiders often enter homes seeking warmth, shelter, and access to a stable food supply, as other insects may also move indoors during winter. However, many of the spiders observed indoors, often called house spiders, have adapted to living inside year-round and were likely born there. They are not typically outdoor species migrating inside for warmth.
Common indoor hiding spots include undisturbed areas like basements, attics, and garages, which offer consistent temperatures and fewer disturbances. Spiders also utilize crawl spaces, wall voids, and areas behind furniture or appliances. They can squeeze through tiny cracks and gaps around windows, doors, or foundations to gain entry.
Winter Life Cycle
The life cycle of spiders during winter varies significantly among species. For many spiders, particularly those with a single-year lifespan, the adults may die as winter approaches after mating and laying eggs. Their offspring then overwinter as eggs, protected within silken egg sacs. These sacs are often placed in secluded, undisturbed locations to safeguard the developing spiderlings from freezing temperatures.
In some species, eggs laid in the fall hatch into tiny spiderlings that remain inside the protective egg sac throughout winter. These young spiders undergo a process of “cold hardening” to survive the cold within their silken enclosures. Other species may overwinter as juveniles or even adults, entering a state of diapause to reduce their activity and conserve energy until spring arrives.