Types of Spiders Commonly Found in California’s Central Valley

California is home to a diverse range of spider species, some of which are more common household pests than others. Understanding the types you might encounter is the first step toward effective spider control.

Western Black Widow Spider

• Identification: Shiny black body, with the female typically having a distinctive red hourglass marking on the underside of her abdomen. Males are smaller and lighter in color.
• Behavior: Prefer dark, undisturbed areas like woodpiles, sheds, garages, crawl spaces, and cluttered areas. Their webs are irregular, strong, and messy.
• Risks: Their venom is neurotoxic and can cause severe pain, muscle cramps, nausea, and in rare cases, more serious complications, especially for children and the elderly.

Brown Widow Spider

• Identification: Typically light brown to gray with an orange or yellow hourglass marking on the underside of the abdomen. Their egg sacs are spiky, resembling a “caltrop” or “sea mine.”
• Behavior: Often found in similar outdoor locations as black widows, but also common in outdoor furniture, planters, and under eaves.
• Risks: Their venom is less potent than the black widow’s, but a bite can still cause discomfort and localized pain.

Wolf Spider

• Identification: Robust, hairy, and often mistaken for small tarantulas due to their size and speed. They are typically brown or gray with dark markings.
• Behavior: Active hunters, preferring to stalk and pounce on their prey rather than building webs. You will often find them on the ground, in leaf litter, or around foundations.
• Risks: While their bite is not considered dangerous, it can be painful and cause redness and swelling.

Orb Weaver Spider

• Identification: Famous for their intricate, circular, wheel-shaped webs, often seen glistening in gardens, fields, and between structures. They come in various sizes and colors.
• Behavior: Generally harmless to humans and are beneficial for controlling insect populations. They rely on web vibrations to detect prey.
• Risks: Not considered dangerous to humans.

Yellow Sac Spider

• Identification: Small, pale yellow spiders with a slightly darker stripe on their abdomen.
• Behavior: They do not build large webs but instead spin small silken sacs in corners of ceilings, walls, or behind furniture, where they hide during the day.
• Risks: Their bites are often mistaken for other insect bites and can cause localized pain, redness, and sometimes a small lesion.

Cellar Spider (Daddy Longlegs)

• Identification: Recognizable by their extremely long, thin legs and small bodies.
• Behavior: They build loose, irregular webs in damp, dark areas like basements, cellars, and crawl spaces. They are known to prey on other spiders.
• Risks: Generally harmless to humans.

Pavement Spiders

• Identification: Small, dark brown to black spiders with pale legs.
• Behavior: Often found outdoors under rocks, logs, and debris, but can enter homes through cracks and gaps. They build small, sheet-like webs.
• Risks: Their bites are generally harmless, causing only minor irritation.

Odorous House Spiders

• Identification: Small, dark brown to black spiders. When crushed, they emit a distinct, unpleasant odor.
• Behavior: Common indoors, often found in kitchens and bathrooms, seeking moisture. They build irregular, tangled webs.
• Risks: Not considered dangerous to humans.

Pharaoh Spiders

While “Pharaoh Spider” is not a recognized common name for a specific spider species, it is possible the user is referring to a spider found in their home that they associate with a “pharaoh” or ancient Egyptian theme, perhaps due to markings or color. It could also be a misidentification of another common household spider. A professional inspection is crucial for accurate identification and effective treatment.

Carpenter Spiders

While not a formally recognized species name, the term “carpenter spider” might refer to spiders found in wooden structures, often associated with moisture-damaged wood. These could include various species seeking shelter or hunting insects attracted to decaying wood. The presence of such spiders can indicate underlying moisture issues or other wood-destroying insect activity, making professional inspection crucial.