Why the confusion is so persistent
The hobo spider myth has a specific origin. In the 1980s and 1990s, case reports from Washington and Oregon described necrotic skin lesions attributed to hobo spider bites. These reports circulated widely, and because giant house spiders look almost identical, BC homeowners began applying the 'hobo' label to every large brown funnel-web spider they encountered. Search engines amplified the myth — searching for 'large brown spider BC' returns hobo spider content from American sources that have no relevance to Metro Vancouver's actual spider fauna.
The scientific picture changed substantially between 2000 and 2017. Controlled venom studies failed to reproduce the necrotic reactions attributed to hobos. The earlier case reports were increasingly re-attributed to MRSA infections, other bacterial skin infections, and brown recluse bites in states where brown recluses actually occur. In 2017, the CDC officially removed hobo spiders from its list of medically significant North American spiders. The necrosis story didn't hold up.
Visual diagnostics: what to look for
Giant house spiders and hobo spiders belong to the same genus (Eratigena) and share a family resemblance. Both are brown, hairy, and build characteristic funnel-shaped sheet webs in low, dark crevices. The differences are there but require careful examination.
| Trait | Giant house spider (E. atrica) | Hobo spider (E. agrestis) |
|---|---|---|
| Body length (female) | 15-20 mm | 11-15 mm |
| Body length (male) | 12-18 mm | 8-11 mm |
| Leg span | 25-50 mm | Up to 45 mm |
| Abdomen pattern | Distinct chevrons, often with central stripe | Similar chevrons, slightly less defined |
| Abdomen colour | Dark brown with lighter markings | Medium brown, more uniform |
| Sternum | Uniform dark brown or black | Lighter, may have pale median stripe |
| Reliable field ID? | Not possible — requires microscopy | Not possible — requires microscopy |
What's actually in BC homes
Eratigena atrica (giant house spider) is well-established across Metro Vancouver, Vancouver Island, and the Fraser Valley. It was introduced from Europe, likely through port activity, and has been a permanent resident for decades. It's the spider in your basement, in garage corners, walking across floors during fall migration. It builds the classic funnel web you'll find tucked into joist bays, behind storage, and in the angles of basement walls.
Eratigena agrestis (hobo spider) has not been documented as an established population in BC. Scattered specimens have been collected near border crossings (Peace Arch, Douglas crossing) by researchers specifically looking for them, suggesting occasional accidental introduction. But no breeding, established population has been confirmed north of the US border. The 2024 BC spider atlas maintained by the Royal BC Museum lists zero confirmed hobo spider records from Metro Vancouver.
The current medical consensus on hobos
Setting aside the BC distribution question: even if you were to encounter a genuine hobo spider in Washington state, the medical risk is now considered low by toxicology consensus. The CDC's 2017 decision was based on a systematic review of venom studies. Injecting purified hobo spider venom into rabbit skin in controlled studies did not produce necrosis. The earlier clinical reports — the ones that created the fear — are now attributed to a combination of MRSA skin infections, other dermatological conditions, and confirmation bias in diagnosing any mysterious skin lesion as a spider bite.
This matters practically: if you develop a skin lesion in BC and your urgent care doctor says 'it looks like a spider bite,' push back and ask about MRSA. Studies at emergency departments in the US Pacific Northwest show that 40–80% of lesions diagnosed as 'spider bites' are actually MRSA. MRSA needs antibiotics. A spider bite does not. Getting the diagnosis right has treatment consequences.
Giant house spider behaviour: what to expect
The giant house spider's life cycle produces the famous fall migration that startles Metro Vancouver homeowners each year. Adult males mature in late summer and abandon their funnel webs to search for females. This is the specimen running across your floor in September — large, fast, and apparently purposeful. It's not hunting you. It's looking for a mate. The males die within weeks after mating. Females overwinter in their webs, lay egg sacs in late autumn, and the juveniles emerge in spring. Understanding this cycle removes most of the alarm. The spider you see in September was living in your garden or basement corner all summer, eating the gnats and silverfish you didn't notice.
- Giant house spiders are not aggressive toward humans. They flee when disturbed and only bite when physically restrained — e.g., trapped in clothing or pressed against skin.
- The bite itself is minor: a small puncture with brief local pain and possibly mild swelling. No necrosis. No systemic symptoms.
- The fall migration season is August through October, peaking in September. It ends with first sustained cold snap.
- Giant house spiders can live 3–7 years as females. You may have the same spider in the same basement corner for several seasons.
- They actively compete with other spider species including European house spiders, which is one reason BC doesn't have an even worse house spider problem.