How to use this guide
Spider identification without a microscope is inherently approximate. Many species cannot be reliably confirmed without examining the genitalia under a dissecting microscope — this is just the biology. What this guide provides is family-level and genus-level identification that's sufficient for pest management decisions. Knowing you have Eratigena (house spider genus) versus Dysdera versus Latrodectus tells you what management response is appropriate, even if you can't confirm the exact species.
The guide is organised by where you encounter them: indoors (including basements, garages, attics), outdoors in gardens and on building exteriors, and at ground level in gardens and lawns. Some species appear in multiple contexts.
Indoor spider species
| Species | Family | Size | Key ID features | Management significance |
|---|---|---|---|---|
| Giant house spider (Eratigena atrica) | Agelenidae | 15-20 mm body, leg span to 50 mm | Large, dark funnel web in corners; fall floor-runner | Low — beneficial, no medical risk |
| European house spider (Tegenaria domestica) | Agelenidae | 10-12 mm body | Smaller funnel web; year-round basement resident | Low — beneficial, no medical risk |
| Cellar spider (Pholcus phalangioides) | Pholcidae | 7-9 mm body, very long legs | Ceiling cobweb; vibrates when disturbed | Very low — beneficial, predates other spiders |
| False widow (Steatoda grossa) | Theridiidae | 6-10 mm female | Dark brown, pale band on abdomen; ground-level cobweb | Low-moderate — bite possible, minor-moderate reaction |
| False widow (Steatoda nobilis) | Theridiidae | 8-14 mm female | Dark brown, cream skull pattern on abdomen | Low-moderate — as above |
| Cross spider (Araneus diadematus) | Araneidae | 10-15 mm female | Orb web near eaves/windows in fall; cross mark on abdomen | Very low — outdoor, enters in fall only |
| Western black widow (Latrodectus hesperus) | Theridiidae | 8-10 mm female | Jet black, shiny; red hourglass on underside; ground cobweb | High — medically significant; call professional |
Garden and exterior wall species
| Species | Family | Size | Key ID features | Ecological role |
|---|---|---|---|---|
| Cross orb-weaver (Araneus diadematus) | Araneidae | 10-15 mm female | Large spiral orb web in fall; cross mark on abdomen | High — major insect pest predator |
| Red-backed jumping spider (Phidippus johnsoni) | Salticidae | 8-12 mm | Black with red abdomen (male); large front eyes; no web | High — aphid predator |
| Wolf spider (Hogna/Tigrosa spp.) | Lycosidae | 15-35 mm | Stocky, hairy; ground hunter; eye-shine; egg sac on abdomen | High — ground pest predator |
| Crab spider (Thomisidae spp.) | Thomisidae | 4-10 mm | Wide body, lateral legs; flower-head ambush hunter | Moderate — flying pest predator |
| Woodlouse hunter (Dysdera crocata) | Dysderidae | 10-15 mm | Orange-red cephalothorax, pale abdomen; large chelicerae; 6 eyes | High — woodlouse predator |
| Garden orb-weaver (Argiope aurantia) | Araneidae | 15-25 mm female | Yellow/black abdomen; large orb web with zigzag stabilimentum | High — insect predator |
Ground and leaf-litter species
| Species | Family | Size | Key ID features | Notes |
|---|---|---|---|---|
| Pardosa wolf spiders (Pardosa spp.) | Lycosidae | 6-10 mm | Slim, brown wolf spider; carries egg sac on spinnerets | Very common on paths, patios |
| Sheet web spiders (Linyphiidae spp.) | Linyphiidae | 2-5 mm | Tiny; flat sheet web in grass, visible when dewy | Beneficial; vast populations in lawn/garden |
| Running crab spiders (Philodromus spp.) | Philodromidae | 5-10 mm | Flat, crab-like; runs on vertical surfaces; bark coloured | Common on exterior walls and fences |
| Nursery web spider (Pisaura mirabilis) | Pisauridae | 10-15 mm | Runs near water; carries egg sac in jaws; nursery tent web | Riparian habitats in Metro Van |
| Tube web spider (Segestria species) | Segestriidae | 8-15 mm | Lives in silk-lined tube in wall crevice; trip-lines radiate from entrance | Exterior walls, old stone, brick |
| Harvestman (Opiliones spp.) | Opiliones (not spiders) | Body 4-8 mm, legs 30-60 mm | Fused body (one segment), no web, bobbing walk | Arachnid but NOT a spider; no venom |
The quick reference: what concerns vs what doesn't
For Metro Vancouver pest management purposes, the complete list of species warranting management action or medical attention breaks down as follows. Medically significant (requires care if bitten): western black widow — emergency if bitten. Warrants professional management if present in occupied areas: western black widow, false widows (Steatoda) near children's areas. Warrants removal if preferred but no medical concern: any spider species in occupied rooms if volumes are high or arachnophobia is a factor. Can be left alone: everything else.
The key insight this list provides: BC's spider fauna is overwhelmingly composed of harmless or beneficial species. The one species on the medically significant list (black widow) is uncommon in Metro Vancouver. The species most likely to cause some discomfort in a bite (false widows) are now establishing in Metro Vancouver and worth knowing about — but they're not a crisis. Everything else you encounter in and around your Metro Vancouver home is, at worst, an aesthetic or quality-of-life concern.