Arachnid · GBIF taxon 2157245
False Black Widow
Steatoda grossaAlso known as Cupboard Spider, Dark Comb-Footed Spider, Brown House Spider, False Widow
False black widows construct sticky, tangled cobwebs in dark corners, basements, and outbuildings to snag crawling insects. Females guard spherical silk egg sacs tucked inside quiet crevices, often living for several years within undisturbed indoor microhabitats. While frequently mistaken for dangerous true black widows, their dark glossy abdomens lack any bright red underside markings.
NocturnalArachnidWeb Weaver
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & prey
- Woodlice
- Ants
- Beetles
Predators
- Centipedes
- Spider wasps
- Birds
ThreatsPesticides, human destruction of webs, extreme cold
HabitatsStructures, basements, sheds, wall cavities, under rocks
Life spanUp to 6 years for females; 1–1.5 years for males
Size / weightNot available
Classification
- OrderAraneae
- FamilyTheridiidae
- GenusSteatoda
- SpeciesSteatoda grossa
Range data is not available yet.
Interaction riskVery high
- Low
- Moderate
- High
- Very high
- Why interaction risk is very high
- Bites are rare and occur defensively when pressed; observe without handling.
- Why it is dangerous
- Bites deliver mild neurotoxic venom causing localized pain, swelling, and occasional temporary malaise known as steatodism.
- How to recognize a risky encounter
- Look for a bulbous purplish-brown to black abdomen with faint pale crescents and no red hourglass.
- What to do
- Avoid pressing against clothing or handling barehanded; use a cup and cardboard for transport.
Responsible observation
- Safe Relocation: Trap spiders under a glass and slide paper beneath to move them outside safely.
- Flashlight Use: Check dark corners in sheds or garages before reaching into unlit spaces.
- Web Maintenance: Leave webs in outbuildings undisturbed to help natural control of house pests.
Look-Alike (c) Justin Williams, some rights reserved (CC BY), uploaded by Justin Williams · cc-by
Frequent Companion (c) RAP, some rights reserved (CC BY), uploaded by RAP · cc-by
Close Relative (c) Dustin Edmundson, some rights reserved (CC BY), uploaded by Dustin Edmundson · cc-by
Close Relative (c) Patrick Hacker, some rights reserved (CC BY), uploaded by Patrick Hacker · cc-by
Help improve the field guideSomething wrong?
Checking your Fauna account…Report a name, category, or profile issue for review.