Brown Widow Spiders in California: A Homeowner's Guide
By the Clark Pest Entomology Team | Last Updated: October 22, 2025
The short answer: The brown widow spider is an invasive species in California, best known for its spiky, tan egg sac and orange hourglass marking.
While related to the black widow, its bite is considered less dangerous, though still painful. They are very common in residential areas, especially in outdoor furniture and cluttered parts of yards.
What Do Brown Widow Spiders Look Like?
Identifying a brown widow is often easier by spotting its unique egg sac rather than the spider itself. The female's body is about 1/2 inch long with long, distinctly banded ("tiger-striped") legs.
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Color: Their color can vary widely, from light tan or gray to dark brown or almost black.
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Markings: They have a geometric pattern on their back (top) and a distinct orange or yellowish hourglass on their belly (underside). This is different from the bright red hourglass of a black widow.
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Egg Sac: This is the most obvious sign. The egg sac is a tan or beige-colored sphere covered in spiky, pointed protrusions. It looks like a tiny sea mine. A single female can produce many of these sacs in a season.
Male spiders are much smaller and are rarely seen.
The brown widow spider (right) and its uniquely spiky egg sac (left). This egg sac is the easiest way to identify them.
Are Brown Widow Spiders Dangerous?
Yes, but they are not considered as dangerous as black widows. Like all widow spiders, the female brown widow is venomous. However, they are known to be very timid and are less likely to bite than their black widow cousins.
A brown widow bite is reported to be painful, but the neurotoxic effects are typically localized and do not have the same severe, systemic impact as a black widow bite. Regardless, if you are bitten, it's important to clean the wound, apply a cold compress, and contact a physician or poison control center for guidance.
Where Are Brown Widows Found in California?
Brown widows are an invasive species from southern Africa that have become widespread in Southern California and are expanding their territory. They have been established from San Diego up through Los Angeles County and as far east as Riverside County.
They are "commensal" spiders, meaning they thrive in and around human structures. They build messy, tangled webs in sheltered, hidden locations. Common hiding spots include:
- Under outdoor plastic furniture (like lawn chairs)
- In and around plastic flower pots
- Under railings and eaves
- In mailboxes and utility boxes
- In cluttered garages or sheds
- Among dense garden plants like birds-of-paradise
When to Call a Professional
You can reduce spider populations by regularly cleaning webs, removing clutter from your yard, and inspecting outdoor furniture. However, because brown widows are so prolific (one female can produce thousands of eggs), an infestation can be difficult to manage on your own.
If you are finding multiple spiky egg sacs or are concerned about the number of spiders in your living area, it's time to call a professional. A Clark Pest Control technician can identify all nesting sites, safely remove spiders and egg sacs, and apply a targeted treatment to protect your home.
Need help with spiders? Call us today at (800) 882-0374 or
request your free inspection.
Frequently Asked Questions About Brown Widows
What's the difference between a brown widow and a black widow?
A: The three main differences are:
1. Hourglass: A black widow has a bright red hourglass. A brown widow has an orange or yellowish hourglass.
2. Egg Sac: A black widow's egg sac is smooth and round, like a small white berry. A brown widow's egg sac is spiky and tan.
3. Bite: A black widow's bite is considered much more dangerous and medically significant.
I found a spiky egg sac. What should I do?
A: You should remove it immediately. Use a stick or a tool (while wearing gloves) to pull it down and place it in a sealed bag. You can then spray it with insecticide or freeze it before disposing of it. This is the most effective way to stop the next generation from hatching.
Are brown widows replacing black widows?
A: In many urban areas of Southern California, yes. Research, including studies from