Giant House Spider
Eratigena duellica (likely)
Agelenidae (Funnel-Web Spiders), Order Araneae
Physical Description
A large, fast-moving spider with a robust, elongated cephalothorax and a slightly smaller oval abdomen. The body is covered in fine, short hairs giving it a velvety appearance. It possesses long, slender legs that contribute to its imposing silhouette.
Size Estimate
Body length typically 10-18mm for females; leg span can reach 2-4 inches (50-100mm) in mature males.
Coloration & Markings
Generally earth-toned, ranging from dark brown to beige or grey. The cephalothorax often features a pale central stripe flanked by darker bands, and the abdomen typically shows a series of chevron-shaped markings or pale spots.
Web Type
Funnel web: a flat, sheet-like web with a funnel-shaped retreat at one end. They do not have sticky silk; they rely on speed to intercept prey that vibrates the sheet.
Eye Arrangement
Eight eyes arranged in two nearly straight rows of four. This setup provides excellent vibration sensing and movement detection rather than high-resolution vision.
Leg Characteristics
Long, hairy legs without thick spines or distinct rings (which distinguishes them from some Tegenaria species). In males, the legs are significantly longer relative to the body than in females.
Venom & Safety Information
Venom Information
Possesses a mild neurotoxic venom used to paralyze small insects. It is not considered toxic to humans and generally lacks significant clinical impact.
Medical Significance
Low medical significance. Bites are extremely rare and usually occur only if the spider is squeezed. Symptoms typically include minor localized pain, redness, or swelling similar to a bee sting.
Safety Recommendations
If found indoors, they can be easily relocated using a cup and a piece of paper. To prevent entry, seal cracks in foundations and ensure window screens are intact.
Habitat & Behavior
Habitat & Range
Commonly found in North America (Pacific Northwest) and Europe. Preferred habitats include dark, undisturbed corners of houses, basements, sheds, and gardens.
Behavior & Temperament
Highly active at night. They are famously fast runners but generally shy and non-aggressive towards humans, preferring to retreat to a crevice when disturbed.
Diet & Prey
Generalist predators feeding on flies, moths, beetles, and even other spiders. They detect vibrations on their web and rush out at high speeds to subdue prey with a quick bite.
Seasonal Activity
Active year-round indoors, but most frequently sighted in late summer/early autumn (August to October) when mature males wander indoors to find females.
Description
The Giant House Spider is a common resident of human dwellings, often startling homeowners due to its impressive size and speed. Despite its fearsome appearance, it is a beneficial roommate that provides natural pest control.
Key Features
Distinguished by its large leg span, 'chevron' abdomen pattern, and high-speed scurrying behavior. Lack of distinct leg banding helps differentiate it from the smaller Barn Funnel Weaver.
Similar Species
Tegenaria domestica (smaller), Eratigena agrestis (Hobo Spider - similar markings but usually smaller and found closer to the ground outdoors).
Life Cycle
Females produce several brownish egg sacs hidden within or near their webs. Spiderlings disperse in spring. Adult males are often seen wandering in late summer and autumn looking for mates.
Ecological Importance
Acts as a major apex predator in the domestic 'micro-ecosystem,' keeping populations of ants, cockroaches, and flies in check.
Conservation Status
Not evaluated by IUCN, but populations are stable and common throughout their range due to adaptation to human environments.
Interesting Facts
At one point, the Giant House Spider held the Guinness World Record for the fastest spider speed (achieving up to 1.73 feet per second).
Photography Tips
Avoid using a harsh direct flash which can wash out the subtle chevron markings. Shoot from a top-down angle to capture the leg span and dorsal pattern for identification.
Identified: 2026-07-09T17:49:38.969975