Giant House Spider
Eratigena duellica (formerly Tegenaria duellica)
Agelenidae (Funnel Weavers), Order Araneae
Physical Description
A large, robust spider with a pear-shaped cephalothorax and an oval abdomen. Long, hairy legs and a somewhat flattened body profile allow it to squeeze into tight crevices. The cephalothorax features two dark longitudinal bands, and the abdomen has a central pale mark with darker chevrons toward the rear.
Size Estimate
Body length typically 10-18mm for females, with a leg span frequently exceeding 75-100mm (3-4 inches). This appears to be a large adult specimen.
Coloration & Markings
Predominantly mottled brown, tan, and grey. The carapace is light brown with two dark, broad longitudinal stripes. The abdomen is greyish-brown with a faint 'herringbone' or chevron pattern of lighter spots.
Web Type
Sheet/Funnel web. It creates a flat, non-sticky horizontal sheet of silk with a tubular retreat (funnel) at one end where the spider hides until prey vibrates the sheet.
Eye Arrangement
Eight eyes of similar size arranged in two slightly curved rows of four. This pattern provides excellent motion detection for fast-moving prey on its web.
Leg Characteristics
Notably long, hairy, and robust. They lack the distinct dark banding found in the closely related Hobo Spider (Eratigena agricola), appearing more uniform in their brownish-orange hue.
Venom & Safety Information
Venom Information
Possesses a standard neurotoxic venom designed to immobilize small insects. The venom is not considered medically significant to humans.
Medical Significance
Low danger level. Bites are rare and typically involve only localized redness, swelling, and mild pain similar to a bee sting. No specialized medical treatment is usually required unless an allergic reaction occurs.
Safety Recommendations
If found indoors, they can be safely relocated using the 'cup and cardboard' method. Wear gloves when moving woodpiles or cleaning dark corners to avoid accidental defensive bites.
Habitat & Behavior
Habitat & Range
Commonly found in the Pacific Northwest of North America and throughout Europe. It prefers dark, undisturbed areas like basements, woodpiles, sheds, and crevices in stone walls.
Behavior & Temperament
Extremely fast runners, once holding the Guinness World Record for spider speed. They are generally shy and will retreat rapidly to their funnel if disturbed. They are not aggressive toward humans and usually bite only if squeezed or mishandled.
Diet & Prey
Generalist predator consuming flies, moths, beetles, and even other spiders. They rely on speed to dash out from their funnel to grab prey that falls onto the silk sheet.
Seasonal Activity
Most visible in late summer and autumn when males wander away from their webs in search of females, often ending up in bathtubs or sinks.
Description
The Giant House Spider is an imposing but misunderstood resident of many homes. Distinguished by its incredible speed and impressive leg span, it is a master of the sheet-web, acting as a natural pest controller by snacking on nuisance insects. Despite its size, it is a timid neighbor that prefers the shadows.
Key Features
Large leg span, distinct dark stripes on the cephalothorax, funnel-shaped retreat in web, and uniform leg coloration without heavy banding.
Similar Species
Hobo Spider (Eratigena agricola) - much smaller and has more distinct abdominal patterns; Domestic House Spider (Tegenaria domestica) - smaller with banded legs; Wolf Spiders - do not build funnel webs and have different eye arrangements.
Life Cycle
Females produce several lens-shaped white egg sacs attached to the web or nearby structures. They can live for 2-3 years, which is longer than many other temperate spider species. Mating typically occurs in late summer or autumn.
Ecological Importance
Critical for indoor and perimeter pest control. They consume a vast number of household pests including flies, earwigs, and ants, maintaining a balance in the local micro-ecosystem.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread, often benefiting from human-modified environments.
Interesting Facts
They were once considered the fastest spiders on land, capable of running up to 1.7 feet per second. They are also known to prey upon the Hobo Spider, helping to keep those populations in check around homes.
Photography Tips
Focus on the top of the cephalothorax to capture the stripe pattern. Use a side-angled shot to emphasize the long legs and use natural light to avoid washing out the subtle abdominal chevrons.
Identified: 2026-07-09T01:27:03.670696