Yes, We have Black Widows in the Bay Area

Yes, We have Black Widows in the Bay Area

I was definitely in denial about black widows.

A friend had talked about seeing black widow spiders in her garden, and I just thought to myself, “she’s mistaken.”

I mean, I’ve lived in the SF Bay Area for more than a dozen years and never heard of anyone seeing one, let alone having any kind of “encounter” with one. I garden, so I spend time in the dark and dirty places spiders love.

I’ve even found brownish/blackish spiders in my house with that suspiciously round boo-tay and checked them for any hourglass tattoos on their bellies, but they were always other kinds of spider. Never a black widow. Never.

Until a fateful day in January.

I opened my green bin to drop in the week’s compost before trash day, and there was this shiny, round-abdomened, black spider, on the lid in a (not to be disparaging, but) messy web. I tapped the lid a bit, to see if it would move. And it did–just a smidge–and just enough to one side that I could clearly, even in the fading light of dusk, see the red hourglass marking on its underside.


So, I did what any normal human who values her life would do: I went into the house to grab my camera and took some pictures. They’re not great (see “fading light of dusk” above) but you can see I’m not hallucinating here, people. 

Close up of Black Widow on a trash can lid
Even in the poor light, and behind her messy web, you can see the red hourglass.

Then, after I gingerly took the garbage bins down to the curb, I did some research on my newfound friend. I hope you find it as useful and interesting as I did.

Are Black Widow Spiders Deadly?

The short answer is: usually not. Just like the seasonal flu, black widow bites are deadly only when they occur in people who are already in a weakened state, like sick or elderly people, or in small children.

That being said, their bites are incredibly painful. One fun bit of trivia is that the pain is sometimes so great, it is mistaken for appendicitis. I’ve had appendicitis, and it hurts so much you vomit and kind of want to die. With that kind of insider knowledge, I’m going to recommend you avoid black widow bites if at all possible.

If you get bitten, elevate the bite area if you can, apply a compress, and get someone to take you to the Emergency room. They will be able to get you the best pain relief and, if you do have an extreme reaction, they can administer antivenom and help you with your breathing.

How can you Identify a Black Widow Spider?

We have a lot of very helpful and not poisonous spiders around the Bay Area, so it’s good to know how to spot the few you should actually be cautious around.

Black widows can be black or brown, and have a shiny, round abdomen.

You won’t find them out in the garden in the sun–you’ll find them inside trash can lids, under and behind things in your shed or garage, and generally away from where you cam easily come across them. They will run away if exposed. They want to stay hidden.

Their webs are not symmetrical, but are instead messy and lacking obvious organization.

And, of course, most have that telltale red hourglass marking on the underside. 

Not all black widows are perfect specimens, however. So, if you’re not totally sure, I’d say avoid contact. And, if you have small kids or pets around the area you’ve found a potential black widow, I’d say kill it just to be safe. Most spiders I’d do my best to save from harm, but I’d rather not see my kids in the kind of pain true black widows can inflict.

Bonus Spider Story

A few months after my first black widow experience, my husband and I were clearing some things around in the garage. I moved a bag of nearly empty compost and discovered a likely black widow underneath. She immediately began running for cover under the bag, so I moved it again to keep her where we could see her while we discussed her fate.

Unbeknownst to us, a male Scrub Jay had noticed the excitement from a power line above. He swooped down next to us, hopped over to the spider, and neatly picked it up and flew to the top of a telephone pole to eat it. That certainly solved our dilemma of how to dispatch of Ms. Spider, but I did read about how eating a black widow can cause tummy troubles for birds. Mr. Jay seemed fine later, but he may think twice about rescuing humans from spiders in the future 🙂

Leave a Reply

Your email address will not be published. Required fields are marked *