Giant House Spider
Eratigena duellica (formerly Tegenaria duellica)
Agelenidae (Funnel Weavers), Order Araneae. Key family characteristics include long, prominent spinnerets and a preference for flat, sheet-like webs leading to a funnel-shaped retreat.
Physical Description
A robust spider with a pear-shaped cephalothorax and an oval abdomen. The body is covered in fine, short hairs giving it a velvety appearance. It exhibits sexual dimorphism, with males having smaller bodies and significantly longer legs compared to females.
Size Estimate
Based on the image, this appears to be an adult specimen. Females typically have a body length of 10-18mm, while males are 10-15mm. Including legs, their span can reach up to 75-100mm (3-4 inches).
Coloration & Markings
Generally dark brown or earthy tan. The cephalothorax often features two dark longitudinal stripes. The abdomen is darker with a series of lighter, pale-yellow chevrons or spotted markings. Legs are solid brown and lack the distinct banding often seen in similar species.
Web Type
Funnel web. They build large, non-sticky horizontal sheets of silk that narrow into a funnel or tube at one end where the spider hides and waits for prey.
Eye Arrangement
Eight eyes of similar size arranged in two nearly straight rows of four. This setup provides a wide field of view for detecting movement above their flat webs.
Leg Characteristics
The legs are exceptionally long and hairy. Unlike many other Agelenid spiders, the Giant House Spider has no rings or bands on its legs. They are built for speed, making them some of the fastest-running spiders in the world.
Venom & Safety Information
Venom Information
Neurotoxic venom used to immobilize small insects. However, the venom is very weak and has no significant effect on human physiology.
Medical Significance
Low medical significance. Bites are extremely rare and usually result in localized pain, redness, or minor swelling, similar to a bee sting. No long-term damage or systemic symptoms occur.
Safety Recommendations
If found indoors, they can be safely relocated using the 'cup and card' method. They are not dangerous and should be left alone if possible to provide free pest control.
Habitat & Behavior
Habitat & Range
Common throughout Europe and the Pacific Northwestern United States and Canada. They prefer dark, undisturbed areas such as basements, attics, woodpiles, and stone walls.
Behavior & Temperament
They are nocturnal, active hunters that rely on extreme speed rather than sticky webs. They are very shy and generally flee from humans, only biting if trapped or pressed against skin.
Diet & Prey
Generalist predators feeding on various insects, including flies, moths, beetles, and even other spiders. They detect vibrations on their web to rush out and overpower prey.
Seasonal Activity
Most visible in late summer and autumn (September-October) during the mating season, when males wander into the open areas of homes searching for females.
Description
The Giant House Spider is an impressive but harmless visitor often found in homes during the cooler months. Known for its startling speed and large leg span, it is actually a beneficial roommate that helps manage indoor pest populations.
Key Features
Large size, lack of leg banding, dark brown body with abdominal chevrons, and very long legs relative to body size.
Similar Species
Eratigena agrestis (Hobo Spider), which is smaller and has distinct patterns on the sternum; and Tegenaria domestica (Barn Funnel Weaver), which has banded legs.
Life Cycle
Females produce several spherical egg sacs containing up to 100 eggs. Spiderlings hatch and disperse via ballooning or crawling. Adults can live for 2-3 years, which is longer than many other common house spiders.
Ecological Importance
Acts as a primary natural controller of household and garden pests. They also serve as a food source for birds and larger predatory insects.
Conservation Status
Not evaluated by the IUCN, but populations are stable and widespread due to their adaptability to human-made structures.
Interesting Facts
Until 2010, this species held the Guinness World Record for the fastest spider, reaching speeds of up to 1.73 feet per second.
Photography Tips
A top-down (dorsal) view is best to capture the abdominal markings and cephalothorax stripes. Use a flash to highlight the fine hairs and eye arrangement.
Identified: 2026-06-17T18:14:19.998903