Common house spider vs Noble false widow
These two are easy to mix up. Here's how to tell a common house spider from a noble false widow, and whether either one bites or stings.
Common house spider
Parasteatoda tepidariorum
Noble false widow
Steatoda nobilis
≠The key differences
Parasteatoda tepidariorum usually has a more mottled, less shiny abdomen and different patterning; body shape and genitalia are reliable distinguishing features for experts.
⚖︎Side by side
| Common house spider | Noble false widow | |
|---|---|---|
| To humans | Mild bite | Mildly venomous |
| Size | Females 5-8 mm body length; males 3-6 mm body length | 6-14 mm body length (females larger, up to around 14 mm; males usually 6-10 mm) |
| Colours | Brown, Tan, Cream, Dark brown | Dark brown, Purplish brown, Cream |
| Family | Theridiidae | Theridiidae |
| Habitat | Sheltered indoor and peridomestic sites: corners, ceilings, basements, attics, garages, window frames, behind furniture and under eaves. | Sheltered, synanthropic locations such as house eaves, garages, sheds, wall cavities and garden outbuildings; also under rocks and in cliff crevices in its native range. |
| Range | Probably native to South America but now cosmopolitan; found across North America, Europe, Asia, and other temperate regions often associated with human structures. | Native to Macaronesian islands; now widespread across western and central Europe, parts of North America, and other regions where it has been introduced. |
| Active | Year-round indoors; most active at night when hunting and maintaining webs. | Active year-round in sheltered indoor sites; outdoors most active in warm months (spring to autumn) and at night. |
| Pest? | No | No |
🔍How to spot a common house spider
- Irregular, three-dimensional tangled web in sheltered indoor corners with a silken retreat.
- Rounded, somewhat bulbous abdomen with variable brown/tan markings.
- Females noticeably larger and more robust than males; males slimmer with visible pedipalps.
- Shorter legs relative to long-legged house spiders; abdomen often patterned rather than uniformly black.
🔍How to spot a noble false widow
- Rounded, glossy abdomen with variable pale cream or tan markings on a dark brown to purplish background.
- Body length about 6-14 mm with females noticeably larger and more bulbous.
- Messy, three-dimensional cobwebs in sheltered corners of buildings, sheds or eaves.
- Legs relatively short compared with some other house spiders and no prominent long spines.
?Frequently asked questions
What is the difference between a common house spider and a noble false widow?
Parasteatoda tepidariorum usually has a more mottled, less shiny abdomen and different patterning; body shape and genitalia are reliable distinguishing features for experts.
Is a common house spider or a noble false widow more dangerous?
Common house spider: Mild bite. Noble false widow: Mildly venomous. Bites are rare and usually occur only if the spider is trapped against skin. Bites are uncommon and occur when the spider is squeezed or trapped against skin.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.