How to recognise a False Widow

The photo of Steatoda nobilis in the previous entry shows a female with the classic pattern of this species. However, here is the other, smaller False Widow, Steatoda grossa, which has a similar pattern, but with a row of triangles in the middle rather than a big pale patch.

A classic example of Steatoda grossa, a female.
A classic example of Steatoda grossa, a female.

So here are the best ways of recognising False Widows:

1. The spider’s abdomen is generally very shiny, like a berry. The spider is hairless.

2. False Widows don’t just hatch out of an egg fully grown. They can be very large, up to 2.5 cm (just short of an inch) when pregnant, and any size under that.

3. The web is a hammock-type web, but unlike the similar Hammock-web Spider, the web of the False Widow is EXTREMELY strong.

4. The spider always hangs upside down from its web.

5. Apart from the male Steatoda grossa, which is a fast runner often wandering into houses in spring (he doesn’t bite for some reason and will happily let you handle him) the female S. grossa and both male and female Steatoda nobilis are extremely slow and clumsy on the ground and actually slip when they walk on smooth surfaces.

6. The False Widow pulls its legs in tight, forming a ball, if knocked from its web or handled. Biting is the very last resort.

7. Both species have two very shiny eyes located at the top front of their heads which virtually glow in torchlight and are among the first things you will notice.

False Widows rest under crevices, usually only coming out at night when birds won’t see them. Birds have no difficulty eating any spider that will fit in their mouths. Anything resting against a wall, or in a sheltered area, or on the outside of a house especially under the eaves will be an attraction to a False Widow. They will enter sheds too, but outside if their preference.

8. False Widows are not afraid to be outside on even the coldest, frostiest nights. It was assumed, because they originate from the Canary Islands that they would fear the cold, but I have seen them outside in their webs when the temperatures were below freezing.

A big female Steatoda nobilis. This is one of the darker ones, with only a white crescent to the front of the big abdomen. They can be all black too, as can Steatoda grossa.
A big female Steatoda nobilis. This is one of the darker ones, with only a white crescent to the front of the big abdomen. They can be all black too, as can Steatoda grossa.

 

10 thoughts on “How to recognise a False Widow”

  1. Hi, my house had been taken over by spiders, at my back door and front door there seem to be hundreds of false widows,(looking at google pics) I’m not to sure, pic to follow, also in my kitchen there has been spiders that look like false widows but are white with a red stripe on it, please advise, thank you, I leave in Navan

  2. Hi Keith,

    There are lots of spiders that will put webs around your back door and windows, but usually these will be the Missing-sector Orb-weaver and window sill spiders. The white one with the red stripe on its abdomen is almost certainly Enoplognatha ovata, sometimes called the egg-bodied spider because its abdomen is the same shape and colour as an egg, albeit much smaller than most. Please feel free to send me a photo of any spiders you are worried about. There are at least two species of False Widow in Ireland and they tend to be a lot larger than the usual spiders that hang on the outside of houses. If a False Widow is on a house it will usually be under the eaves among the gutters in a very tangled web with no discernible shape to it. Any spider in a classic spider web is okay and not a false widow or any other kind of widow spider. Also, false widows are very timid and not a bit aggressive. They generally stay put once they find a good location. I hope that helps ease your mind to some degree.
    Sam

  3. I think I may have a false widow and babies in my bathroom there is a spider which hides and comes out mostly at night then when the smaller spiders are active it will come out too.

  4. Hi Holly,

    Is the spider in a web or just walking about. If it’s just walking it’s probably not a False Widow. If it has a web and it hangs upside-down from it then it probably is a False Widow. Otherwise it’s something else, probably a Window Spider – Amaurobius. Where in the bathroom is it located? Do you have a photo of it?
    Best regards,
    Sam

  5. I have a big female on my balcony but only active at night, There is a lot of smaller spiders active at night in the same web. Are the smaller spiders male or just young? Found a male or ‘small’ one hanging from the light shade in my room.

  6. Hi Colin,
    If they are very small spiders they could be young False Widows but it’s possible they are spiders of a different species that look similar which have pitched their webs very close to the adult False Widow’s. False Widow spiders make very strong webs and other spiders are not above using the anchor lines as burresses to support their own webs. Its does sometimes end badly for them though. Many thanks for your comment! Sam

  7. Love this post, the detail and healthy message you’re delivering here. I’ve got a beautiful *i think* s. nobilis female who dwells behind my security light on the front of my house.

    I think she’s a beaut to be honest! I leave for work at 5am and get home around 8, and she always peaks out to say hi 🙂

    I hate the demonisation of these spiders by the UK media.. I’m not a massive spider lover, and try not to handle them if at all possible… But I refuse to ever harm a spider, and prefer to leave them be or relocate them if they’re upsetting my family.

    Can I send you a pic of my little pal though for a positive ID? I think she’s lived there for over a year now, is that possible? What’s their life expectancy?

  8. Hi Ryan, Thanks for the kind words about this post. False Widow spiders certainly do love to pitch their webs behind porch lights and security lights, aparently to allow them snatch moths and other insects. It’s a weird thing about them – Steatoda grossa craves darkness and dark places whereas Steatoda nobilis doesn’t seem to mind bright light at all, but is still mainly nocturnal to avoid bird predation (presumably). There has been a lot of media hype about False Widow bites lately, but in none of the caes I’ve read has the spider been seen and it seems the species carrying out the bites are being assumed, but a lot of the symptoms of these hype bites sound much more like Brown Recluse spiders which are in the UK now. I’ll be in contact directly so you can send on your photo. Many thanks, Sam

  9. Hi

    Hi

    I think I may have a false widow in my bedroom and I think it’s a she. Is there a way I can u a picture please. I run a cat rescue and I’m a little worried. I know this is following an old thread but your discrimination and replies make me think this is what I have now a few feet from my bed….

    Kind regards

    Louise Cardiff

    Greystones Kitty Hostel

  10. Hi Louise, I’m very sorry I’m so late replying to this. False widows are not nearly so dangerous as people think. Let me know if you have any more issues. For some reason I never got the email alert for your message. Best regards, Sam

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