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. The cephalothorax features two dark longitudinal bands. The body is covered in fine, bristly hairs, giving it a velvety texture. This specimen appears to be a female or a sub-adult based on the abdomen size and pedipalp structure.
Size Estimate
The body length is approximately 15-18mm with a leg span likely reaching 3-4 inches (75-100mm). This is consistent with an adult female specimen.
Coloration & Markings
Mottled brown, tan, and grey. The cephalothorax has dark stripes, while the abdomen features a series of paler chevrons or 'heart marks' along the midline flanked by darker spots. The legs are generally a solid brownish-grey with subtle, darker ring-like markings near the joints.
Web Type
Builds a flat, sheet-like funnel web made of non-sticky silk. The web usually leads back into a secure crevice or 'funnel' where the spider retreats when disturbed.
Eye Arrangement
Eight eyes of similar size arranged in two nearly straight rows of four. This arrangement provides excellent motion detection for guarding the funnel entrance.
Leg Characteristics
Long, thick, and hairy legs equipped with sensitive bristles (trichobothria). In the photo, the legs show dark banding at the distal ends of the segments. They are built for high-speed sprinting rather than climbing smooth surfaces.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for paralyzing insects. It is not considered medically significant to humans; the venom is weak, and the spider is reluctant to bite.
Medical Significance
Low danger level. Bites are rare and usually only occur if the spider is squeezed. Symptoms are typically limited to minor localized pain, redness, and swelling, similar to a bee sting.
Safety Recommendations
Use a glass and a piece of paper to safely relocate them outside if they are unwanted indoors. Wear gloves when moving woodpiles or rocks where they may hide.
Habitat & Behavior
Habitat & Range
Commonly found throughout Europe and the Pacific Northwestern United States and Canada. Preferred habitats include dark, undisturbed areas like basements, sheds, rock piles, and woodpiles.
Behavior & Temperament
Extremely fast runners but generally shy and non-aggressive. They prefer to retreat into their funnel at the first sign of vibration or light. They are active primarily at night.
Diet & Prey
Generalist predator eating variety of insects, including flies, beetles, and moths. They also hunt other spiders, including the hobo spider, which they are known to outcompete.
Seasonal Activity
Most visible in late summer and autumn (September-October) when mature males leave their webs to find mates, often appearing in sinks or bathtubs.
Description
The Giant House Spider is one of the largest spiders found in temperate homes. Despite its intimidating size and incredible speed, it is a beneficial 'roommate' that provides excellent pest control.
Key Features
Distinguished by its large leg span, 'chevron' pattern on the abdomen, and the two dark longitudinal stripes on the carapace.
Similar Species
Often confused with the Hobo Spider (Eratigena agricola) or the Domestic House Spider (Tegenaria domestica). It is larger than both and lacks the specific leg markings associated with the hobo spider.
Life Cycle
Females can live for several years. They produce several white or greyish egg sacs during their lifetime. Mating typically occurs in late summer or autumn when males wander in search of females.
Ecological Importance
Crucial for controlling indoor and garden pest populations. They act as a natural check on populations of flies and other house-dwelling insects.
Conservation Status
Not evaluated by the IUCN, but populations are stable and widespread in urban and suburban environments.
Interesting Facts
For its size, this spider is one of the fastest in the world, once holding a Guinness World Record for speed (clocked at nearly 1.73 feet per second).
Photography Tips
Focus on the 'top-down' view to capture the carapace stripes and abdominal patterns. Low-angle shots can highlight the impressive leg span and hairy texture.
Identified: 2026-06-22T03:58:46.429611