Spiders do not “hate” the cold, but their survival is directly tied to temperature due to their physiology. As ectotherms, their body temperature is regulated by their external environment. Unlike warm-blooded animals, spiders rely on external heat sources to maintain metabolic processes, making them highly susceptible to temperature fluctuations.
How Cold Affects Spiders Physically
Low temperatures significantly impact a spider’s physical capabilities by slowing down crucial biological processes. When cold, their metabolism decreases, leading to reduced activity and slower digestion. This slowdown affects muscle function and nerve impulses, making movement and hunting difficult. Enzymes, essential for nearly all biological reactions, become less efficient in colder conditions. Spiders become sluggish and less mobile when temperatures drop, conserving energy until warmer conditions return.
Where Spiders Go When It’s Cold
When temperatures fall, spiders exhibit behavioral adaptations to find more stable and warmer microclimates. They seek shelter in protected environments that offer insulation from extreme cold. Common overwintering spots include cracks in foundations, under rocks, leaf litter, or burrows in the soil. Some species may also find refuge inside homes, though house spiders are typically different species adapted to indoor conditions. This search for shelter is a crucial strategy to avoid the harshest temperatures and find locations where they can safely enter a state of reduced activity.
Spider Survival Strategies in Winter
Spiders employ various physiological adaptations to survive freezing temperatures. Many species produce “antifreeze” compounds, known as cryoprotectants, in their hemolymph. These substances lower the freezing point of their bodily fluids, preventing ice crystals from forming and damaging cells. Another strategy is supercooling, where the spider’s body fluids remain liquid even below their normal freezing point without ice formation. Many spiders also enter a state of dormancy or diapause, a period of significantly reduced metabolic activity akin to hibernation, which conserves energy during times of cold and food scarcity.
Lethal Temperatures and Spider Tolerance
Despite their adaptations, spiders have a temperature threshold below which they cannot survive. The formation of ice crystals within their tissues is ultimately fatal, as it ruptures cells and disrupts vital bodily functions. While some species can tolerate temperatures below freezing, prolonged exposure to extreme cold leads to death.
The specific lethal temperature varies significantly by species, depending on their natural habitat and evolved cold hardiness. For instance, some active winter spiders can survive down to -4°C but die at -7°C, while others can withstand temperatures as low as -10°C or even -20°C. Prolonged cold is often fatal for spiders not specifically adapted to such conditions.