Giant House Spider
Eratigena duellica (often grouped under Giant House Spider complex)
Agelenidae (Funnel-web weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair notably elongated, and building sheet webs that funnel into a retreat.
Physical Description
Robust body with a distinctly patterned, oval-shaped abdomen and a longer, darker brown cephalothorax. Covered in fine setae (hairs) giving a velvety appearance.
Size Estimate
Body length approximately 10 to 18 mm for females, with a leg span reaching up to 40 to 60 mm. This specimen appears to be a sub-adult or adult male.
Coloration & Markings
Mottled brown and yellowish coloration. The cephalothorax features lighter longitudinal markings, while the abdomen exhibits a complex chevron or herringbone pattern with yellowish spots.
Web Type
Flat sheet web (funnel web) with a tubular retreat at one end, typically spun in dark, undisturbed corners, behind furniture, or in basements and sheds.
Eye Arrangement
Eight small eyes of roughly equal size arranged in two slightly curved, horizontal rows across the front of the cephalothorax.
Leg Characteristics
Long, strong, and tapering legs equipped with visible spines and subtle dark banding. Legs are held sprawling out to the sides.
Venom & Safety Information
Venom Information
Contains neurotoxic venom used to immobilize insect prey. It is low in potency relative to humans and cannot cause significant systemic harm.
Medical Significance
Harmless to humans. Bites are extremely rare and generally only occur if the spider is directly squeezed. Symptoms, if any, are mild and localized like a minor bee sting.
Safety Recommendations
No special safety measures needed. If found in a bathtub or sink, safely relocate it outdoors using a cup and a piece of paper. No professional pest control is necessary.
Habitat & Behavior
Habitat & Range
Native to Europe, introduced to the Pacific Northwest of North America and other temperate regions globally. Prefers damp, cool structures, cellars, outbuildings, and woodpiles.
Behavior & Temperament
Timid and fast-moving. Will typically flee rapidly toward its funnel retreat when disturbed. Rarely aggressive unless trapped against skin.
Diet & Prey
Generalist predator feeding on crawling insects such as beetles, woodlice, flies, and other spiders caught in its sheet web.
Seasonal Activity
Most commonly seen in late summer and autumn when mature males actively leave their webs to wander in search of mates.
Description
The Giant House Spider is a familiar yet harmless indoor companion in many temperate regions. Known for its impressive size and incredible running speed, it spends most of its time waiting motionlessly in a silken funnel web constructed in dark corners or basements, playing a vital role in natural pest control.
Key Features
Elongated posterior spinnerets, a mottled chevron pattern on the abdomen, long spiny legs, and construction of a sheet web with a funnel retreat.
Similar Species
Hobo Spider (Eratigena agrestis). Distinguished by subtle differences in internal genitalia and slightly more uniform leg coloring, though behavior and appearance heavily overlap.
Life Cycle
Females construct silken egg sacs in autumn, guarding them through the winter. Spiderlings emerge in spring, undergoing multiple molts to reach maturity with a lifespan of up to several years.
Ecological Importance
Acts as an effective apex predator of household and garden insect pests, helping naturally regulate populations of flies, beetles, and roaches.
Conservation Status
Not evaluated by the IUCN, but populations are extremely secure, widespread, and frequently thrive alongside human habitations.
Interesting Facts
Despite their intimidating size, they are poor climbers on smooth vertical surfaces like porcelain and bathtubs, which is often how homeowners encounter them trapped.
Photography Tips
Photograph from above to capture the full dorsal pattern of the abdomen and leg banding. Use natural lighting or an off-camera flash to reduce harsh reflections on shiny surfaces.
Identified: 2026-09-20T21:37:32.052898