Seeing a spider in your home may give you the heebie-jeebies, but they are common in California homes. For the most part, these house spiders in California are harmless, but it helps to be able to identify these eight-legged creatures when you see one. This is a list of common house spiders found in the state of California.
7 House Spiders in California
1. American House Spider
Scientific Name: Parasteatoda tepidariorum
As the name suggests, these spiders are often found inside the home. While they can bite, their venom is not toxic to humans. American House spiders have a bulbous abdomen and are brown in color with white or darker patches and lines.
They tend to build webs in the corners of your home, especially near a window. They capture insects in their webs, inject them with venom, and then save them to be eaten later. While these eight-legged creatures may give you the heebie-jeebies, they are very helpful in controlling the insect population inside your home.
2. Domestic House Spider
Scientific Name: Tegenaria Domestica
This common house guest is typically dark brown or orangish-brown in color and has stripes on its legs. They can be found in dark, quiet spaces like cabinets and undisturbed rooms like attics, basements, and garages. You might even find one behind the couch.
They like the dark, quiet, secluded spaces. Domestic House Spiders are not aggressive, and they rarely bite. Luckily, even if they did bite, their venom is not harmful to humans. These small creatures start out life in an egg sac and reach maturity in about a year. They can live up to 7 years.
3. Desert Recluse
Scientific Name: Loxosceles deserta
These common house guests are particularly unwelcome because they have a venomous bite that is especially dangerous to kids and pets. Their bite can cause necrosis, which is the death of living tissue. If this sounds unpleasant, it’s because it is. It isn’t uncommon for victims of these spider bites to require skin grafts on the affected area.
Desert recluses are brown in color and, as their name implies, are particularly shy. They avoid humans and tend to build their homes in secluded areas like closets and porches. They are also nocturnal, which means they are more active at night.
Much like Brown Recluse spiders, which, despite popular belief, do not reside in California, Desert Recluses have a violin-shaped pattern on their backs. Their bodies tend to be about a half inch long, and their leg span can be up to two inches. They live up to three years, and their diet consists of small insects.
4. Western Black Widow
Scientific name: Latrodectus hesperus
The Western Black Widow is one of the few venomous spiders in California. With this species, it is only the adult females that are dangerous. An adult female Western Black Widow is shiny and black with an orange or red hourglass shape on the abdomen.
The males and juvenile females are smaller, not as black and shiny, and lack a prominent hourglass shape. Despite common beliefs, these spiders are not aggressive.
They only bite when provoked and often don’t inject their venom when they bite a human. Many Western Black Widow bites are uncomfortable but harmless. If one injects venom, you may experience nausea, vomiting, and other symptoms, but you won’t be in any real danger.
5. Wolf Spider
Scientific Name: Lycosidae
These hairy creatures are typically gray, black, or brown in color and grow up to almost one and a half inches. They are fast and relatively large. Wolf spiders are not aggressive, but if provoked, they will bite, causing redness, itchiness, and pain.
Unlike other spiders, wolf spiders carry their egg sac around with them, attached to their abdomen. After the egg hatches, the mother’s young climb onto her abdomen, where they remain for several weeks until they are old enough to take care of themselves. While you will find these spiders all over the US, they are particularly common in California.
6. Cellar Spiders
Scientific Name: Pholcus phalangioides
As their name suggests, these spiders often occupy basements, sheds, garages, and even cellars if you have one. Most types of Cellar Spiders have disproportionately long legs and small bodies. Their body size is typically less than half an inch.
Cellar Spiders eat insects and other spiders, but they find ants to be a particularly tasty treat. Like Wolf Spiders, the mother Cellar Spider carries her egg sac around with her, except that she carries it in her jaw rather than attached to her abdomen. Chances are, if you have a house, you have a cellar spider somewhere in the dark corners of your basements, attics, and cellars.
7. Yellow Sac Spider
Scientific Name: Cheiracanthium
These unique, pale-colored spiders can be found climbing along the ceiling and walls of your home. They do not build webs but rather construct small tube-like structures or “sacs” that they hide out in during the day.
They are most active as the sun goes down, which is when they emerge from their sacs and hunt for food, including other spiders. A female Yellow Sac Spider can produce up to five egg sacs after mating. Each sac contains up to 48 eggs.
That’s a lot of babies! If you see a Yellow Sac Spider in your home, use care when handling them. If provoked, they will bite, and their venom is toxic to humans. The effects are usually mild but noticeable.