Wolf Spiders in Southern California: Big, Fast, and Mostly Harmless

It's almost always at night, it's almost always on the floor, and it is always moving. A big brown spider comes out from under the bookcase, crosses six feet of tile faster than anything with eight legs has a right to, and vanishes under the couch. Now nobody wants to sit on the couch. If that sounds familiar, and especially if it happened this fall, there's a good chance you just met a wolf spider.

Wolf spiders are built for running. They are sturdy, hairy and long-legged, with a body that sits low to the ground. Southern California has several species and they vary in size, but the ones that end up in living rooms tend to be the bigger ones, often around the size of a half-dollar or more with their legs spread. That size, plus the speed, is most of why they are alarming.

The coloring is camouflage: brown, gray, tan and black in mottled patches or stripes, often with darker lengthwise stripes on the front section of the body. On bare dirt, mulch or dry grass they disappear completely, which is the point. On a pale tile floor at 11pm, they don't.

If you can get a look at the face (a phone camera zoomed in from a respectful distance works fine), wolf spiders have a distinctive eye arrangement. There are eight eyes in three rows: four small eyes along the bottom, two large eyes facing straight forward above them, and two more on top of the head looking up and back. Those two big forward-facing eyes give the spider a look of paying attention to you, because it is. Wolf spiders hunt by sight more than most spiders do.

Those eyes also reflect light. Walk the yard at night with a flashlight held up near your own eyes and you may see tiny green-white glints in the grass or mulch. Many of those are wolf spiders, sitting still and waiting for something to wander past. It's a little unsettling the first time and interesting after that.

Female wolf spiders carry their egg sac attached to the back end of the body, a round grayish-white ball they drag along wherever they go. When the eggs hatch, the spiderlings climb onto the mother's back and ride around for a while before dispersing. If you have ever seen a lumpy-looking spider seem to fall apart into dozens of tiny spiders when someone swatted it, that was a wolf spider mother. It is also the best argument there is for the cup-and-card method over the shoe.

Most spiders people know build a web and wait. Wolf spiders go looking. They hunt at night on the ground, either stalking prey or sitting perfectly still until something gets close enough to pounce on. Some species live in silk-lined burrows in the soil or under stones and wait at the entrance. None of them rely on a web to catch food.

That is why the encounter always plays out the same way. You don't find a wolf spider sitting in a corner. You find one in motion, crossing open floor, usually heading for the nearest dark gap. When it seems to run at you, it is usually running toward the shadow under your chair or the gap behind your feet. They move in bursts, stop dead, and start again, which makes them hard to catch and easy to lose.

Indoors, a wolf spider is in the wrong habitat. It is there because it followed something to eat or slipped in looking for shelter, and it usually doesn't settle in the way web-building house spiders do. They don't form colonies, and one wolf spider in the den is not the leading edge of an infestation.

They can, but they rarely do. A wolf spider would much rather run than fight, and bites mostly happen when one gets pressed against skin: stepped on barefoot, trapped in a shoe or a glove, or picked up. Their venom is not considered medically significant for people. For most people a bite means local pain, redness and some swelling, a lot like a bee sting, and it settles on its own.

As with any bite or sting, some people react more strongly than others. Wash the spot with soap and water, use a cold pack for the swelling, and keep an eye on it. If redness is spreading, the pain is getting worse instead of better, there are signs of infection, or anyone has trouble breathing, get medical care. This is general information rather than medical advice, and a physician is the right person for anything that isn't settling down.

Doctors also point out that a lot of skin sores blamed on spider bites turn out to be something else, such as a skin infection. If nobody actually saw a spider bite, that is another reason to have a sore that is getting worse looked at rather than assuming.

A cup and a stiff piece of paper, the same as any other spider. Lower the cup over it, slide the paper underneath, and walk it out to the garden. A vacuum works too if you can't face that. If it's in the garage, honestly, you can leave it there. It is eating things you want gone.

One wolf spider in October is not a pest problem. Seeing them regularly indoors is a different message, and the message is usually about what they are eating. A steady supply of crickets, earwigs, silverfish or cockroaches is what keeps hunters coming in, and those insects usually point back to moisture, clutter or open entry points at ground level.

That is the part a professional visit can help with. An inspection looks at where insects are getting in, where they are living around the foundation and in the garage, and what is drawing them. For ongoing insect pressure, a recurring general pest plan focused on the perimeter is usually the right tool, and quarterly visits are our usual recommendation for a typical home. If you also have web-building spiders around the eaves and windows, dewebbing can be added on or done as a one-off.

And if you aren't sure what kind of spider you're looking at, a clear photo helps, along with where you found it and what it was doing.