Giant House Spider
Eratigena duellica
Agelenidae (Funnel Weavers), Order Araneae
Physical Description
A large, robust spider with a pear-shaped cephalothorax and an oval-shaped abdomen. The body is covered in fine, short hairs giving it a velvety appearance. Females are larger-bodied, while males have longer legs and conspicuous palps.
Size Estimate
Body length 10-18mm; leg span can reach 50-100mm (2-4 inches). This specimen appears to be an adult.
Coloration & Markings
Predominantly earthy browns, tans, and greys. The cephalothorax features two dark longitudinal stripes. The abdomen typically has a pale central 'cardiac mark' flanked by darker chevron patterns or spots.
Web Type
Builds a flat, sheet-like funnel web made of non-sticky silk. The web typically ends in a tubular retreat where the spider hides, waiting for vibrations.
Eye Arrangement
Eight eyes of similar size arranged in two rows that are slightly curved, typical of the Agelenidae family for detecting motion across a horizontal plane.
Leg Characteristics
Long, hairy legs without distinct banding (unlike the closely related hobo spider). Legs are powerful, designed for high-speed sprinting rather than climbing smooth vertical surfaces.
Venom & Safety Information
Venom Information
Neurotoxic venom used to immobilize small insects. It is not considered toxic to humans and lacks the necrotic components found in more significant species.
Medical Significance
Harmless. Bites are rare and usually occur only if the spider is squeezed. Symptoms are typically limited to mild localized pain and swelling, similar to a bee sting.
Safety Recommendations
If found indoors, they can be easily relocated using the cup-and-paper method. Wear gloves if handling woodpiles where they may hide. There is no need for chemical extermination.
Habitat & Behavior
Habitat & Range
Commonly found throughout Europe and the Pacific Northwest of North America. They prefer dark, dry unused areas such as basements, attics, woodpiles, and crawl spaces.
Behavior & Temperament
Extremely fast runners but generally shy and non-aggressive. They prefer to flee rather than bite. They are primarily nocturnal hunters that stay in their webs but males wander in late summer.
Diet & Prey
Insects such as flies, beetles, and moths, as well as other spiders. They rely on speed to ambush prey that lands on their sheet web.
Seasonal Activity
Most visible in late summer and early autumn (August to October) when mature males leave their webs to wander in search of females.
Description
An impressive and often misunderstood resident of many homes, the Giant House Spider is one of the fastest invertebrates in the world. Despite its intimidating size and speed, it is a beneficial roommate that provides excellent pest control.
Key Features
Distinguished by its large size, brown chevron abdomen patterns, lack of leg bands, and the preference for funnel-shaped webs in corners.
Similar Species
Eratigena agrestis (Hobo Spider) which is smaller with shorter legs; Tegenaria domestica (Barn Funnel Weaver) which is smaller and usually has banded legs.
Life Cycle
Females produce several globe-shaped egg sacs containing dozens of eggs. They can live up to 2-3 years, which is longer than many other temperate spider species.
Ecological Importance
Act as a primary indoor predator for nuisance insects like silverfish, house flies, and clothes moths, maintaining an ecological balance inside man-made structures.
Conservation Status
Not evaluated by IUCN; common and stable throughout its range with no significant threats.
Interesting Facts
Until 1987, it held the Guinness World Record for spider speed, clocked at 1.73 feet per second. They are also known to outcompete and even prey upon hobo spiders.
Photography Tips
Focus on the dorsal (top) pattern of the cephalothorax and abdomen. Use a macro lens or high-resolution zoom to capture the lack of bands on the legs for definitive identification.
Identified: 2026-06-15T01:36:25.272302