Giant House Spider
Eratigena duellica (formerly Tegenaria gigantea)
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include long spinnerets and the construction of flat, sheet-like funnel webs.
Physical Description
A large, robust spider with a typical pear-shaped cephalothorax and an oval-shaped abdomen. The body is covered in fine hairs, giving it a velvety appearance. In this specimen, the enlarged pedipalps (bulbs at the front) indicate it is a mature male.
Size Estimate
The specimen appears to be an adult male with a body length of approximately 12-15mm. Total leg span for this species can reach 50-100mm (2-4 inches), making them among the largest spiders in their range.
Coloration & Markings
Tones of earthy brown, tan, and grey. The cephalothorax features three light longitudinal bands. The abdomen has a central pale 'herringbone' or chevron pattern consisting of six spots or marks. The legs are generally solid brown without distinct banding.
Web Type
Funnel web. They build flat, non-sticky sheets of silk that lead into a protective tubular retreat in a corner or crevice. They do not hunt on the web but wait for vibrations to rush out and grab prey.
Eye Arrangement
Eight eyes of similar size arranged in two rows that are slightly curved. This arrangement provides excellent motion detection for their high-speed dashes.
Leg Characteristics
Long, slender, and powerful legs designed for high-speed running. They are covered in fine sensory hairs (trichobothria) and lack the heavy spines seen in wolf spiders.
Venom & Safety Information
Venom Information
Possesses a mild neurotoxic venom used to paralyze insect prey. The venom is not considered medically significant to humans.
Medical Significance
Harmless. Bites are rare and usually only occur if the spider is squeezed or trapped against skin. Symptoms are typically limited to mild localized pain and redness similar to a bee sting.
Safety Recommendations
If found, they can be easily safely relocated using the 'cup and paper' method. Glue traps like the one pictured are effective for monitoring but can be avoided by sealing cracks and reducing clutter in basements.
Habitat & Behavior
Habitat & Range
Commonly found in the Pacific Northwest of North America and throughout Europe. They prefer dark, undisturbed areas such as basements, crawl spaces, sheds, and garages.
Behavior & Temperament
Extremely fast runners but generally shy and non-aggressive. They prefer to flee rather than bite. Males are highly active in late summer and autumn as they wander in search of mates.
Diet & Prey
Generalist predators feeding on various household insects, including flies, beetles, moths, and even other spiders (including the Hobo spider). They use speed to overwhelm prey.
Seasonal Activity
Active year-round indoors, but most visible in August through October during the mating season when males move into living spaces.
Description
The Giant House Spider is a common, large arachnid often encountered indoors during the autumn. Despite their intimidating size and incredible speed, they are beneficial roommates that provide excellent natural pest control. This specific individual is a wandering male, likely searching for a female's web.
Key Features
Large leg-to-body ratio, chevron patterns on the abdomen, long posterior spinnerets, and a lack of distinct leg banding.
Similar Species
Often confused with the Hobo Spider (Eratigena agrestis), which is smaller and has different sternum markings, or Wolf Spiders (Lycosidae), which have much larger primary eyes and a different hunting style.
Life Cycle
Females can live for several years, while males typically die shortly after mating. They produce several white, papery egg sacs throughout the year, containing up to 60 eggs each.
Ecological Importance
Crucial for controlling indoor and perimeter insect populations. They are also known to outcompete and prey upon more concerning species like the Hobo spider.
Conservation Status
Not evaluated by the IUCN; however, they are a very common and stable species across their range.
Interesting Facts
The Giant House Spider held the Guinness World Record for the fastest spider for many years, capable of reaching speeds of up to 1.73 feet per second.
Photography Tips
To assist with identification, try to capture a clear top-down (dorsal) view of the abdominal patterns and the arrangement of the eyes.
Identified: 2026-06-15T01:29:29.958605