Top 5 Venomous Spiders in California

| Categories: Spiders

Venomous spiders can be found in many parts of the world, and California is no exception. There are several venomous spider species that call California home. These spiders vary in appearance, but they all share one thing in common: they can deliver a painful and potentially deadly venom.

All of these venomous spiders are most active during the summer months. They inhabit in many different parts of California, including urban areas, agricultural land, and forests.

While venomous spiders are certainly dangerous, fatalities are rare. Nevertheless, they can be a nuisance that you don’t want around your home. If you do happen to see a venomous spider, it is best to leave it alone and call a professional for help.

5 Most Common Poisonous Spiders in California

There are many venomous spiders found in California, but the five that we will focus on are the western black widow, brown widow, brown recluse, yellow sac spider, and desert recluse.

Western Black Widow

The western black widow is the most dangerous of all spiders. Its venom is 15 times stronger than a rattlesnake’s venom. These spiders are typically found in the western United States, and they love to live near humans. Their webs are often located in dark, secluded areas like under rocks or inside sheds, crawlspaces, basements, barns, and woodpiles. Black widows are most active in warmer temperatures over 70 degrees.

The western black widow has a shiny black body with a red hourglass shape on its abdomen. They have eight legs and eight eyes. A young black widow spider is mostly orange and white, but as it matures, its color turns red and black. Females are much larger than males, with bodies that can grow between 14-16mm in length, and they can deliver a very painful bite. Although fatalities are rare, this spider should always be treated with caution.

The presence of webs in your home or on your property can be a sign that there’s an infestation of black widows. If you encounter a western black widow, stay calm and back away slowly. Do not attempt to touch or kill the spider as it may bite you. Call a spider control expert like Pro Pacific so we can safely remove black widows from your home.

Brown Widow

The brown widow is brown or grayish-brown in color and can be distinguished from other venomous spiders by its orange hourglass marking. A male brown widow’s body can grow 6-8mm long, while a female brown widow’s body can grow 12-16mm long. Mature brown widows look almost the same as young western black widows, so you might get confused when you see them. To spot a brown widow, look for the white dots on their abdomen.

This spider can be found throughout California and is well-established in the southern urban areas of San Diego, San Marcos, and surrounding suburbs. Black widows are most active during the fall and winter months, often hiding in dark, moist places such as under leaves, cracks or crevices, and closets. 

It is important to be aware of these spiders and take precautions when working or playing outside in areas where they may be present. Bites from brown widows are extremely painful but not likely to be severe as a black widow’s bite. Nevertheless, one should seek medical attention if bitten by a brown widow.

Brown Recluse

Unlike the western black widow and brown widow, the brown recluse is less recognizable as they have dull brown colors that many spiders possess. Identifying a brown recluse can be tricky. It has a violin-shaped marking on its head, appearing near the eyes through the neck down toward the abdomen.

Do note that a red marking can also be found in some other spiders, and not all brown recluses have it. Hence, it’s not the most precise method to identify the spider. The best way to identify them is by counting their eyes — brown recluses only have six eyes compared to most spiders with eight.

The brown recluse is found throughout California but is most common in the central and southern parts of the state. It’s most active during the spring and summer months, hiding in darker, quieter, and warmer places such as under leaves, in cracks or crevices, and closets.

Brown recluse spiders should be treated with utmost caution. As one of California’s most poisonous spiders, the brown recluse can cause necrosis (the death of tissue) or even death with its bite. The first symptom of its bite is red, itching skin followed by an open sore, which usually comes with a rash of tiny red spots, fever, and nausea. Anyone who is bitten by a brown recluse should seek medical attention.

Yellow Sac Spider

The yellow sac spider is a common sight in California. You can tell a yellow sac spider by its distinctive pale yellow body. It has eight eyes equally divided into two rows. Female yellow sac spiders lay 30-48 eggs and protect them using their silk sac, which is a lot if they survive and grow into adult spiders.

This spider is most active during the spring and summer months, around March until October. It doesn’t build webs. Instead, it creates a flat silk sac and uses it to pass during the day, which often can be found in dark, moist places such as under a leaf, ceiling line, cracks, closets, and other protected spots.

The yellow sac spider is not considered dangerous, but it bites if they feel threatened. Its bite can cause redness, swelling, and sometimes even necrosis and is very painful. If you see a yellow sac spider, it’s best to leave it alone and contact a professional if you need help getting rid of it.

Desert Recluse

The desert recluse has a smooth, light brown body that grows up to 13mm long. Due to their similar appearance, desert recluse, and brown recluse are often mistaken interchangeably. They both have six eyes arranged in three groups of two and a violin-shaped marking on their bodies.

It’s most active during the fall and winter months. The desert recluse’s favorite spot to crash is in shrubs and cacti in desert areas (that’s why they’re called such) of California, New Mexico, Arizona, and Nevada, especially during the fall and winter months. However, they can be found in other arid environments, such as those in California.

The desert recluse is not aggressive, although it can bite you if it feels in danger. Like the brown recluse, desert recluses are known to have necrotic venom. Its bite can cause swelling and redness. Seek professional help if you find one. 

Get Professional Help From a Spider Control Expert in California

Spiders are the second most common pest our customers complain about. While they are important to eliminate unwanted insects, living with venomous spiders at home is not safe for you and your kids as they can cause painful, even deadly bites on humans.

If you need spider control experts, Pro Pacific Pest Control can help you get rid of spiders at home and prevent them from coming back. Learn more about our Spider Pest Control & Extermination Service, or directly call us at 800-901-1102 to schedule a free inspection and estimate for your spider control job.

Call for Immediate Attention

Or fill out the form below anytime!

  • Preferred free inspection time:

    Scheduling subject to availability

  • This field is for validation purposes and should be left unchanged.

Fill out the form to contact us at any time!

  • Preferred free inspection time:

    Scheduling subject to availability

  • This field is for validation purposes and should be left unchanged.

Service Areas