Hobo (Eratigena agrestis)
For thirty years the hobo spider carried a reputation it never earned. A plain brown funnel weaver from Europe that settled in the Pacific Northwest, it was blamed for wounds it almost certainly never caused — until the evidence was re-examined and the CDC dropped it from its list of venomous spiders in 2017.
By Dr. James WatuwaPublished August 10, 2019Updated September 13, 2026✓ Reviewed by Dr Richard J. Pearce (PhD)
In this guide
Physical description and identification
The hobo spider is a medium-sized, unremarkable brown spider built for speed on flat ground. Short fine hairs give it a matte, dusty look, and the legs are long, slim and — importantly — plain. Nothing about it is showy, which is exactly why it is so often misidentified.
Adults
- Size: females measure about 11–15 mm in body length and males 8–11 mm. With the legs extended the spider covers roughly 25–45 mm (1–1.8 in), well short of the leg spans often quoted for the species.
- Color: uniformly brown to greyish brown, with two faint darker bands on the carapace. The legs are a single even shade with no rings or mottling — one of the few features a person can use without a microscope.
- Eyes: eight small eyes of similar size in two nearly straight rows, typical of the funnel weavers. Vision is poor; the spider hunts by feeling vibration in its sheet.
- Distinctive features: the oblong abdomen carries a row of pale, forward-pointing chevrons, and a pair of long posterior spinnerets projects visibly beyond its rear. Males have swollen pedipalps like small boxing gloves; females are heavier and blunter. Certain identification rests on the male palpal organ or the female epigyne under magnification, which is why no one can confirm a hobo spider from a photograph of the whole animal.
Eggs and egg sacs
Females build egg sacs mainly in September. Each is a flattened disc of white silk about 10 mm across, fastened under a stone, board or window ledge near the web and camouflaged with soil and silk. A female may produce up to four sacs, each holding on the order of 50–100 eggs, which overwinter and hatch in spring.
Spiderlings
Juveniles emerge in late spring, disperse a short distance and start their own small sheets almost immediately. They grow through a series of molts and, in most of the North American range, run on a roughly two-year cycle: hatch one spring, overwinter as juveniles, mature the following summer.
The web
The hobo spider builds a flat, slightly dished sheet of silk — often compared to a trampoline — that narrows at one end into a funnel where the spider waits. The silk is not sticky; it works as a trip surface and a vibration antenna, delaying an insect just long enough for the spider to sprint out, bite and carry it back. Webs sit at or near ground level in foundation cracks, retaining walls, window wells and wood piles, and are expanded rather than rebuilt, so old ones look grey and dusty. See our guide to spider webs for how this differs from an orb weaver's glue-lined spiral.
Where hobo spiders live
Eratigena agrestis is native to Europe, from the Atlantic coast eastward into Central Asia. There it is an ordinary field and embankment spider with no reputation at all — a point worth remembering, because it is the same species that became notorious in North America. It lives under stones, in grass banks and on rubble, and only occasionally comes indoors.
It was introduced to the Pacific Northwest and first recorded near the port of Seattle in the 1930s. It is now established in Washington, Oregon, Idaho, Montana, Utah and Wyoming, and in southern British Columbia and Alberta in Canada.
Everywhere it occurs it is a ground-level animal that climbs smooth vertical surfaces poorly, so indoor sightings concentrate in basements, crawl spaces, garages and ground-floor bathrooms rather than on ceilings.
Are hobo spiders venomous?
Yes — like almost all spiders it uses venom to subdue insects. The question that matters is whether that venom is medically significant to people, and the research literature now answers no.
From the late 1980s the hobo spider was widely blamed for slow-healing, ulcerating skin wounds in the Pacific Northwest, filling the role the brown recluse plays elsewhere. That claim rested on case reports in which the spider was rarely positively identified, and on rabbit experiments that later investigators could not reproduce. Subsequent work found no dermonecrotic activity in hobo venom and no unusual bacteria on the fangs, and reviews by Richard Vetter and colleagues concluded there is no reliable evidence tying the species to necrotic lesions. In 2017 the CDC removed the hobo spider from its list of venomous spiders of medical concern.
It is equally telling that in Europe, where the spider is native and abundant, it has never been linked to necrotic wounds.
Can hobo spiders bite?
A hobo spider can bite, but it does so rarely and in self-defence — typically when pressed against skin inside clothing, bedding or a shoe. It is not aggressive; faced with a hand it runs, and a running hobo spider looks alarming mainly because it is fast.
Where bites have been verified the effects are minor and local: a brief sting, redness, mild swelling and occasional itching that settle within a day or two. No deaths have ever been attributed to this species, and the sequence of numbness, blistering and blackened tissue described in older articles reflects the discredited necrosis hypothesis rather than documented outcomes.
First aid is the same as for any minor spider bite: wash with soap and water, apply a cold pack, keep the area clean. Seek medical advice if it becomes hot, spreads, discharges pus or comes with fever — signs of a bacterial skin infection, a far more common explanation for a wound blamed on a spider. If you can safely keep the spider or a clear photo, bring it.
Hobo or giant house spider? Look at the legs. A hobo spider's legs are a plain, even brown. A giant house spider, the species most often mistaken for it in the same region, is larger with legs visibly banded or mottled. Neither is dangerous.
Ecological importance and behavior of the hobo spider
The hobo spider is a sit-and-wait predator. It rests in the funnel with its front legs on the silk, reads the vibration of anything that lands on the sheet, and decides in a fraction of a second whether to attack or retreat. Prey is whatever walks at ground level: ants, beetles, earwigs, sowbugs, crickets, small cockroaches and flies.
Natural predators: ground beetles, centipedes, spider-hunting wasps, shrews, birds and larger spiders. In the Pacific Northwest the introduced giant house spider is a documented predator and competitor, and its spread appears to have pushed hobo spiders out of many houses they once occupied.
Prey-predator dynamics: because the sheet is fixed and cheap to maintain, success depends almost entirely on placement. A warm foundation crack beside a grass bank is worth defending, and a displaced spider usually has to fight or settle for a poorer site.
Seasonal behavior: activity peaks from late July to October, when mature males leave their webs to search for females. Almost every hobo spider seen running across a floor is a male in this phase, and he will die within weeks of mating. Females stay with the web and may overwinter.
Relationship with humans: a beneficial, harmless neighbour that spent decades being blamed for injuries it did not cause. If the webs are unwelcome, sweeping them away and sealing gaps at floor level works better than any spray.
Similar spiders and how to tell them apart
| Spider | How it differs from the hobo spider |
|---|---|
| Giant house spider (Eratigena atrica) | Distinctly larger and bulkier, with legs and palps banded or mottled with dark patches. Shares the same houses in the Pacific Northwest and is the single most common source of "hobo spider" reports. |
| Barn funnel weaver (Tegenaria domestica) | Smaller and more slender, with clearly ringed legs and a paler, strongly mottled abdomen. Far more tolerant of dry indoor rooms and found across both North America and Europe. |
| Grass spiders (Agelenopsis) | Native North American funnel weavers with two bold dark stripes on the carapace and very long spinnerets. They build their sheets in the open on lawns and shrubs, not in wall cracks. |
| Brown recluse | Six eyes in three pairs, a violin mark on the carapace, no chevrons, and a loose irregular retreat instead of a sheet web. Absent from the hobo spider's North American range. |
| Australian funnel-webs (Atracidae) | Unrelated, despite the shared word "funnel". They are mygalomorphs with downward-striking fangs, restricted to eastern Australia, and genuinely dangerous. The hobo spider is an araneomorph agelenid. |
Quick facts
| Distribution | Native across Europe and into Central Asia; introduced and established in the Pacific Northwest and south-western Canada. |
|---|---|
| Habitat | Ground level: foundation cracks, retaining walls, window wells, wood piles, grass banks, basements and crawl spaces. |
| Diet | Ants, beetles, earwigs, sowbugs, crickets, small cockroaches and other ground-dwelling arthropods. |
| Lifespan | Usually two years; males die within weeks of mating, females may overwinter a second time. |
| Predators | Ground beetles, centipedes, spider-hunting wasps, birds, shrews and larger spiders, including the giant house spider. |
| Web | Flat, non-sticky sheet with a funnel retreat at one end, built at or near ground level. |
| IUCN status | Not evaluated. Common and widespread across its native and introduced range. |
Did you know?
- The alternative name "aggressive house spider" is a translation error. The epithet agrestis is Latin for "of the fields", describing where the spider lives — not its temperament — but it was read as "aggressive" and the misnomer stuck for decades.
- Baron Charles Athanase Walckenaer described it in 1802 as Aranea agrestis. It spent nearly two centuries in Tegenaria before a 2013 revision of the European funnel weavers moved it into the new genus Eratigena — a name that is an anagram of Tegenaria.
- Because the species cannot be identified reliably without magnification, surveys that asked the public to submit "hobo spiders" repeatedly found that most specimens were something else entirely.
In summary, the hobo spider is a fast, plain, ground-dwelling funnel weaver that earns its keep eating insects and has been cleared by the evidence of the injuries once attributed to it. Learn its unbanded legs and forward-pointing chevrons, and treat a wandering male in autumn for what he is: a harmless spider looking for a mate.
Frequently asked questions about the hobo
How do you identify a hobo spider?
Look for a plain brown spider 8–15 mm long with long posterior spinnerets, an oblong abdomen bearing a row of pale forward-pointing chevrons, and legs of one even shade with no dark rings. Males have swollen boxing-glove pedipalps. Certain identification needs a microscope, so treat any field call as provisional.
Are hobo spiders venomous to humans?
Hobo spiders are venomous to insects but not medically significant to people. The older claim that their bite causes necrosis rested on unreplicated laboratory work and case reports without confirmed spider identification. The CDC removed the species from its list of venomous spiders in 2017, and no necrotic bites are recorded in Europe.
How big is a hobo spider?
Adult females have a body length of about 11–15 mm and males about 8–11 mm. With the legs extended the spider covers roughly 25–45 mm, or one to just under two inches. Much larger leg spans quoted for this species almost always refer to giant house spiders instead.
What does a hobo spider web look like?
It is a flat, slightly dished sheet of dense white silk that narrows at one end into a tube-shaped funnel where the spider waits. The silk is not sticky; it works by tripping insects and carrying vibration. Webs sit at ground level in wall cracks, window wells, wood piles and grass banks.
How many eggs does a female hobo spider lay?
A female builds up to four disc-shaped egg sacs, mostly in September, each containing roughly 50 to 100 eggs. She fastens them under a stone, board or ledge near her web and camouflages them with silk and soil. The eggs overwinter and the spiderlings emerge in spring.
What is the difference between male and female hobo spiders?
Females are larger and heavier bodied with a rounded abdomen and slim pedipalps. Males are smaller, longer legged and carry conspicuously swollen pedipalps that resemble boxing gloves and are used to transfer sperm. Males also wander in late summer and autumn, while females stay with the web.
Can a hobo spider bite a person?
Yes, but bites are rare and defensive, usually happening when the spider is trapped against skin in clothing or bedding. Verified bites cause short-lived local pain, redness and mild swelling that resolve within a day or two. Wash the area, use a cold pack, and see a doctor if infection develops.
How do I tell a hobo spider from a giant house spider?
Check the legs and the size. Giant house spiders are noticeably bigger and have legs and palps marked with darker bands or mottling. Hobo spiders are smaller with legs of one uniform brown. Both build funnel webs, both are harmless, and giant house spiders will even eat hobo spiders.
Where do hobo spiders live in the United States?
They are established across the Pacific Northwest and the northern Rockies, including Washington, Oregon, Idaho, Montana, Utah and Wyoming, plus southern British Columbia and Alberta. They are not found in the southern or eastern United States, so a brown spider in Texas or Georgia is not a hobo spider.
Why do hobo spiders run across the floor in autumn?
Those are mature males that have abandoned their webs to search for females, which happens mainly from late July through October. They travel at ground level, enter houses through gaps under doors and around basement windows, and die within a few weeks of mating. Cup them and put them outside.
References
- World Spider Catalog (2026). Eratigena agrestis (Walckenaer, 1802). Natural History Museum Bern. wsc.nmbe.ch/spec-data/7292/taxon
