Hobo Spider, Aggressive House Spider
Eratigena agrestis
Agelenidae (Funnel-weaving spiders), Order Araneae. Key family characteristics include long spinnerets and a distinctive funnel-shaped web.
Physical Description
A robust, brown-patterned spider with a clearly segmented body consisting of a cephalothorax and abdomen. It has a slightly elongated abdomen featuring distinct chevron or herringbone patterns down the dorsal center, and a relatively hairy, sturdy build.
Size Estimate
Body length typically ranges from 11 to 18 millimeters for females and 9 to 15 millimeters for males, with a total leg span reaching up to 40 to 45 millimeters.
Coloration & Markings
Predominantly brown tones, ranging from yellowish-brown to dark brown. The cephalothorax features inconspicuous or absent distinct dark stripes. The dorsal abdomen has a clear series of dark chevron or herringbone markings pointing forward.
Web Type
Builds a characteristic non-sticky funnel web. The web consists of a flat sheet of silk with a tubular retreat or funnel at one end where the spider waits for prey.
Eye Arrangement
Eight small eyes of roughly equal size arranged in two slightly curved, nearly parallel horizontal rows across the front of the carapace.
Leg Characteristics
Long, robust legs covered in fine hairs and spines. Unlike some other species, the legs generally lack distinct dark bands or rings, appearing mostly uniform brown.
Venom & Safety Information
Venom Information
Contains a necrotic venom that can cause localized tissue damage in laboratory mammals, though human reaction and the exact medical significance remain subjects of ongoing scientific debate.
Medical Significance
Historically considered dangerously venomous with bites causing necrotic lesions, modern arachnological consensus suggests many attributed hobo spider bites may have been misdiagnosed or caused by secondary infections. Bites can cause localized pain, redness, and occasional blistering.
Safety Recommendations
Wear gloves when moving firewood or cleaning out dark basements. Shake out shoes and clothing left on the floor. If bitten, wash the area thoroughly with soap and water and apply a cold compress.
Habitat & Behavior
Habitat & Range
Native to Europe and Central Asia, introduced to the Pacific Northwest of North America. Found in fields, under rocks, in woodpiles, and frequently around human habitations in dark, undisturbed areas like basements, crawlspaces, and gaps behind baseboards.
Behavior & Temperament
Typically non-aggressive, fleeing when disturbed. They rely on their funnel webs to detect vibrations from passing prey. Bites generally only occur when the spider is trapped directly against human skin.
Diet & Prey
Generalist predators feeding primarily on ground-dwelling insects such as beetles, flies, roaches, and other spiders, which are subdued in their funnel webs.
Seasonal Activity
Most active during late summer and autumn, particularly during the mating season when mature males actively wander in search of females.
Description
The hobo spider is a quintessential funnel-weaver, known for its distinctive sheet-like webs found near ground level in dark corners, woodpiles, and foundations. Though once widely feared for its supposed flesh-melting bite, it is generally reclusive and avoids human contact whenever possible.
Key Features
Absence of distinct dark banding on the legs, lack of striking patterns on the cephalothorax, and the presence of a distinct herringbone or chevron pattern running down the center of the abdomen.
Similar Species
Giant house spider (Eratigena atrica) and domestic house spider (Tegenaria domestica), which are generally larger or have different leg banding and sternum markings.
Life Cycle
Females lay eggs in silk egg sacs hidden within the funnel web or nearby crevices in the autumn. Spiderlings hatch in spring, undergo multiple molts, and reach maturity by late summer or early autumn, typically living for 1 to 3 years.
Ecological Importance
Serves as an effective natural predator of various crawling insect pests around human dwellings and in natural ecosystems, helping to balance local invertebrate populations.
Conservation Status
Not evaluated by the IUCN, but populations are secure, thriving, and expanding in both native and introduced ranges.
Interesting Facts
The common name 'hobo' stems from the mistaken historical belief that the species migrated along railway tracks across the Pacific Northwest.
Photography Tips
Photograph from a safe distance using a macro lens. Capture the dorsal view of the abdomen to clearly show the chevron markings and ensure proper lighting to highlight the lack of leg banding.
Identified: 2026-10-02T19:49:09.415130