Where do Spiders go in Winter?
The Credit River Watershed is home to a remarkable diversity of spiders, many of which slip out of sight as winter settles in. Yet their survival strategies during the cold winter months reminds us even the smallest creatures depend on healthy, connected habitats to survive.
Spiders survive winter by sheltering in leaf litter, downed wood, wetlands and forest floors, habitats that persist when ecosystems remain intact. Learning about their remarkable strategies to survive cold temperatures helps us understand how essential these natural spaces are and why our work matters.
Ongoing habitat restoration, land stewardship and long-term monitoring helps protect the forests and wetlands that provide insulated overwintering spaces, allowing spiders and other small wildlife to endure seasonal extremes and re-emerge each spring.
Winter marks a critical period in the life cycle of spider species in our watershed. Rather than remaining active, most rely on specific overwintering strategies such as seeking shelter and aligning their life cycles with the seasonal changes. As temperatures drop, they retreat into microhabitats that provides insulation, stability and helps them conserve energy through the cold months.
Depending on the species, spiders may overwinter as:
- Eggs: sealed inside thick, protective silk egg sacs.
- Juveniles: hidden beneath leaf litter, soil, rocks or tree bark.
- Adults: sheltered in crevices, hollow plant stems or sheltered areas around buildings.
These winter refuges create stable, buffered environments where spiders can remain dormant until conditions warm again in spring.
Built-in Cold Protection
Spiders are cold-blooded but many species are surprisingly cold-tolerant. As temperatures drop, they produce natural compounds, including glycerol and other sugar-based molecules that function like antifreeze. These substances lower the freezing point of body fluids and help prevent damage to cells.
Some spiders can tolerate partial freezing, while others avoid freezing altogether by remaining dry and protected. These physiological adaptations are well documented in scientific studies of overwintering arthropods in northern climates.
Dock Spiders Overwinter as Juveniles
The largest spiders commonly found in Ontario are dock or fishing spiders (Dolomedes species). In this region, Dolomedes triton typically overwinters as juveniles rather than as eggs, taking up to two years to reach adulthood and surviving more than one winter before maturing.
Found near wetlands and shorelines, dock spiders are known not only for their size but also for their parental care. Female dock spiders carry their egg sacs in their fangs and later build nursery webs to protect newly hatched spiderlings.
Why Spiders Matter Year-round
Even in winter, spiders continue to play an important ecological role. While many species overwinter as eggs or remain hidden as juveniles or adults, some spiders can be active on milder winter days, including those seen moving across snow or leaf litter when conditions allow.
Spiders that shelter in forests, wetlands and urban greenspaces help regulate insect populations early in the spring, supporting balanced food webs. Indoors, common house and basement spiders remain active year-round, quietly helping to keep household pest populations in check.
The Big Picture
Winter offers a reminder that many species in the watershed rely on subtle, often unseen adaptations to survive. While spiders may be out of sight in February, they remain an essential part of healthy, resilient ecosystems.
Discover how you can get involved in our programs and events to take conservation action at home and in your community.
Learn more about insects and other arthropods in the Credit River Watershed.
By Laura Timms, Program Manager, Natural Heritage