False black widow
Despite its resemblance to true black widows, this spider's bite is far milder, though it has occasionally caused pain, swelling and nausea needing medical care.
| Where | Buildings, sheds and dark corners |
|---|---|
| Size | Female 6.5 to 10 mm, male 5 to 10 mm body length |
| When | January to December |
The False black widow is a plain, purplish brown cobweb spider that resembles a true black widow but lacks any red hourglass mark; adult females are often almost patternless, while juveniles and males show faint triangular and bar shaped markings. Its body ranges from pale yellowish brown to nearly black, and its legs are unbanded.
It lives almost entirely in and around buildings, favouring low, hidden spots such as under furniture, in sheds and garages, where it waits in its web through the night to catch woodlice and other crawling insects. Occasional bites on people have caused pain and swelling, and rare cases have needed hospital treatment.
Traits
Habitat
Towns
Colour
Brown, Black
Active
Night
To people
Mild
Bites are uncommon but documented, causing pain, swelling and sometimes nausea that usually settle within a day or two; wash the bite and seek medical care if symptoms spread or do not improve.
Activity through the year
Often confused with
Usually shows a reddish abdomen with a pale cream band near the front, unlike the False black widow, which is more uniformly purplish brown and often nearly patternless in adult females.
Questions
Is the False black widow dangerous to people?
Mild. Bites are uncommon but documented, causing pain, swelling and sometimes nausea that usually settle within a day or two; wash the bite and seek medical care if symptoms spread or do not improve.
When can you see the False black widow?
The False black widow can be seen from January to December, at night.
Plate retouched from a photo by Don Loarie, CC BY 4.0, iNaturalist Licence
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Spiders›Cobweb spiders›Steatoda
Last updated 2026-09-27. Every entry is checked against published sources.