# Ontario Household Spider Identification Guide — Spider Squad

## How to Use This Guide

Spider identification is most reliable with a combination of features: body size, colour and markings, leg characteristics, web type, and location found. A photo is always helpful — a clear photo of the spider and, if visible, the web allows for confident identification.

## Quick Reference: Ontario's Most Common Household Spiders

| Spider | Size | Colour | Web Type | Most Common Location |
|--------|------|--------|----------|---------------------|
| House spider | 4-6mm | Tan/brown mottled | Tangled cobweb | Corners, window frames, storage areas |
| Cellar spider | 6-9mm body, very long legs | Pale grey | Loose irregular web | Basements, crawl spaces, dark corners |
| Wolf spider | 10-30mm | Brown/grey with markings | No web | Ground level, basements, behind objects |
| Jumping spider | 5-12mm | Variable, often black/orange | No capture web | Sunny walls, window frames, gardens |
| Orb weaver | 5-28mm (species varies) | Variable | Classic circular web | Exterior eaves, gardens, doorways |
| Yellow sac spider | 5-10mm | Pale yellow/cream | Silk tube retreat (not capture web) | Ceiling-wall junctions, trim, windows |
| Dock spider | 17-25mm body | Dark brown with pale markings | No capture web | Waterfront, docks, shoreline structures |

## Identification by Where You Found It

**In a web in the corner of a room:** House spider (tangled, 3D web) or cellar spider (loose, irregular web with very long-legged spider)

**On the basement floor, fast-moving, no web:** Wolf spider

**On a sunny exterior wall, seems to be watching you:** Jumping spider (large forward-facing eyes, compact body)

**Large circular web in the garden or across the eaves:** Orb weaver spider (late summer to fall)

**Small, pale, near the ceiling:** Yellow sac spider (look for silk tube retreat nearby)

**Near water or on a dock:** Dock spider / fishing spider

**Very large, dark, under the dock:** Dock spider (Dolomedes)

## Identification by Body Features

**Eight eyes in two rows of four:** Most common Ontario spiders (house spider, wolf spider, jumping spider, orb weaver, cellar spider)

**Very large front-facing eyes visible from in front:** Jumping spider — the most distinctive feature

**Six eyes in three pairs:** Would suggest brown recluse (NOT established in Ontario — see the brown recluse page)

**Glossy black with red marking on underside:** Black widow (rare — see the black widow page)

**Violin-shaped marking on front body section:** Would indicate brown recluse (not in Ontario; likely misidentified)

**Egg sac attached to underside of abdomen:** Wolf spider female (she carries the egg sac attached to her spinnerets)

**Small spiderlings visible on large spider's back:** Wolf spider female with newly hatched young

## Dangerous vs. Not Dangerous: Ontario Summary

The vast majority of Ontario household spiders are harmless to humans. The two species with notable venom risk in Ontario:

**Yellow sac spider:** Most likely common spider to produce a notable bite reaction. Bites can cause localized necrotic reaction in some individuals. Not life-threatening for most people.

**Black widow (rare in Ontario):** Potent neurotoxin. Seek medical attention for suspected bites. Very rare in Ontario — primarily in rural southwestern Ontario and isolated Niagara Peninsula sightings.

Everything else you're likely to encounter in an Ontario home — house spiders, wolf spiders, cellar spiders, jumping spiders, orb weavers — is physically harmless.

## Getting a Confident ID

- Photo tips: get the spider in focus from above (dorsal view) and from the side. A second photo of the underside is helpful for any black spider. Include something for scale.
- If you can catch the spider, a small jar with a lid allows for a later inspection without release risk.
- For professional identification of uncertain Ontario specimens, contact the Royal Ontario Museum Entomology department or a university natural history collection.

For individual species pages: spidersquad.ca/spiders/