Venomous Spiders in California


You should be aware of a few venomous spiders in California to make sure you know what they look like. It’s also important to make sure you know what the bites look like so you can protect yourself as much as possible. 


Difference Between Poisonous and Venomous Spiders


Poisonous spiders can release their toxins when inhaled, absorbed, or ingested through the tissue and skin. So, they are only considered harmful if you eat them. They are generally less problematic because your chances of eating them are extremely rare unless you happen to cook into a dish and not know. 

Venomous spiders, on the other hand, are more worrisome because they inject their toxins by biting or stinging, so they are harder to avoid. This means you need to be extra careful when in places where these spiders might be found because they could sting or bite you before you know it. 


The Most Common Venomous Spiders in California


There are several venomous spiders you need to look out for when you are in California, whether you are just visiting or living there. The most common venomous spiders you might encounter are the black widow spider, the brown widow spider, and the yellow sac spider. 

You might also spot the Desert Recluse Spider or the Chilean Recluse Spider. These spiders can only be found in Southern California, so you don’t need to worry about them unless you are in that area. 


What should you do when you see a venomous spider?


When you see a venomous spider, the first thing you should do is to leave it alone. You should not go near it or try to get a closer look. If you see it outside on your property, it’s best to just leave it alone. However, if it’s near your entry door or where you leave the house, you might want to try and kill it so that it does not come into the house or bite someone when they are trying to escape. 

Remember that spiders that are venomous eat other predators around the home, so if it’s on your property but not near the doors, you might want to just leave it alone. If it’s in the house, you want to make sure you find it and kill it right away so that it doesn’t sneak into your bed or another place where it can bite you. 


6 Poisonous California Spiders


Spiders have around 39 different species found in the state of California. They can range in color and sizes. One thing is for sure they are unwanted pests in your home. Spiders, however, do provide an excellent service and aren’t all bad. They can kill off many of the insects you also wouldn’t want to come in contact with. The problem with some of the variety of spiders is that they can be poisonous. While often, their poison is reserved for prey or other smaller insects that would seek to do them harm, it can be somewhat irritating if humans are bitten. It’s important to know what are the common spiders in California that won’t hurt you, and which ones are the poisonous spiders in California, that you should avoid. For instance, California is home to the largest wolf spider in North America, and this specific spider is not harmful. On the other hand, the black widow is poisonous and can have some serious complications. Let’s take a look at the some of the most commonly found spiders you might come across.


Long-legged sac spider

One Long-Legged Sac Spider


These spiders have the potential to be poisonous although seldom do they bite. Those that are sensitive to their venom can experience painful sensations at the site of the bite. It typically will take months to be fully healed. The long-legged sac spider likes residing in homes and can usually be found under surfaces. They are considered not extremely dangerous because they don’t often bite humans.


California trapdoor spider

California Trapdoor Spider


This spider sometimes gets confused with a tarantula, because they have a similar appearance. They are often found in homes and are usually found in Southern California. They may seem a little frightening, but they are not as harmful as other species.



The Black and Yellow Garden Spider


These spiders, specifically the females, are known for both their size and vibrant yellow and black coloring. They are not poisonous to humans and are commonly found in the gardens and orchards.


Desert Recluse Spider


Desert Recluse Spiders are ones you should definitely be on the lookout for because you don’t want to get bit by them. The bite of these spiders is toxic and can damage your skin and the surrounding tissues of the place where it bit you. These lesions can take a long time to heal, and they can cause serious problems if not treated correctly. 


Appearance and Habitat


Desert Recluse Spiders are found in California and the Sonoran and Mojave Deserts and can also be found in Arizona, Nevada, Utah, and New Mexico.

Desert Recluse Spiders can be hard to spot because they are only a half-inch long. They can easily hide, and you might not see them before they bite. So, if you see a tiny spider though that has long legs, it might be a Desert Recluse. These spiders can often have legs that are 2 inches long or bigger. 

They are tan or yellowish-tan in color. Their undersides are usually light brown, and they often have fiddle-shaped markings on their backs. Desert Recluse spiders also have six eyes. 


Life Cycle and Habits


Once a Desert Recluse spider is an adult, they live about one to two years. The female Desert Recluse spiders will produce several egg sacs during a period of about two to three months. They usually lay their egg sacs around May to July. There will usually be about fifty eggs in one sac. The eggs will take about one month to hatch, and then the baby Desert Recluse spiders will take about one year to grow into adulthood. 

Desert Recluse spiders have particular nesting habits. They usually spin irregularly shaped webs in areas that are mostly undisturbed. They are almost always found outdoors, so you will not find them indoors except on rare occasions.

They usually feed on small live insects or large dead ones. So, you might find the nests of Desert Recluse spiders outside your property somewhere that is further away from your home.  


How to spot a desert recluse spider’s web?


The strands of a Desert Recluse spider’s web are often off-white in color, and you will usually find them in undisturbed locations rather than close to your home or on your porch. The webs are often found in dark areas if they are found indoors, although they are usually outside. If you find them inside, you might find them in basements, cellars, crawlspaces, ductwork, and closets. 


Brown Recluse Spider


Brown recluse spiders are a well-known spider in California because most people have often seen them in the news or may have even seen one around their house or property before. They can be found in many different areas of the United States, with California just being one of the states you can find them. 


Appearance and Habitat


The brown recluse has very unique violin markings. Mature adult spiders often have darker violin shapes than babies or young adult spiders. The violin shape should point towards the abdomen’s bulb side. Sometimes the violin shape can be hard to spot if you have never seen it before, so you might want to see if you can look at the eyes. Most spiders have eight eyes, but the brown recluse spiders have only six on them.


Life Cycle and Habits


Brown Recluse spiders take about a year to mature and have an average lifespan of about 2 to 4 years. Females can produce 5 egg sacs in their lifetime. One of the significant habits you should know about when it comes to Brown Recluse spiders is that they can easily live indoors without being seen. 

They can even live in your attic or basement during the winter without dying. These resilient qualities make them very dangerous and allow them to stay in your home for long periods and even cohabitate with you. Along with living in the winter pretty easily, they can also live in the summer very easily, even without food and water. So, they can survive the cold and the heat. 

They usually hunt at night because this is the best time to find insect prey. They also eat insects, whether they are alive or dead. They typically make their way inside their homes through the cracks, and they usually like to stay in dark, sheltered areas of the house. 

They might often be found in areas of your home where they can find insercts, including cockroaches, beetles, silverfish, firebrats, crickets, and many other small insects. 


How to spot a brown recluse spider’s web?


The brown recluse spider’s web strands are usually off-white in color rather than clear. Unlike other spiders, the brown recluse spider does not use their web to trap the prey. So, you will not find prey inside the web of the brown recluse’s spider web. Remember that the spider actively hunts for food rather than keeping prey inside the web. 


Western Black Widow Spider


Black widow

The Black Widow


The western black widow spider is found in all the western regions of North America. They build very irregular webs that are usually tunnel-shaped. The females are the venomous ones, and they often eat their male after mating, making them more terrifying than other spiders. 

The black widow has a reputation for being one of the scariest, and one that is most easily recognized. A bite from a black widow can result in serious health issues such as shortness of breath and muscle aches. While only 5% of those that have been bitten have led to death, this is one spider you do not plan to mess with. 


Appearance and Habitat


Female western black widow spiders are about ½ inch in length. They are black and have an hourglass mark on the lower abdomen that is usually red. On rare occasions, the hourglass shape can be yellow or white. The male is only ¼ inch long, making them even harder to find. 

The male spider is tan in color rather than black. They also have lighter striping on the abdomen and live in many different western parts of North America, including throughout the whole state of California. 


Life Cycle and Habits


The male and females will usually mate on the web because the female spider becomes stimulated when they come in contact with the male’s web. The silk also contains certain scents that allow the spiders to mate. 

The western black widow feeds on different kinds of insects, including beetles, weevils, ants, wasps, and bumblebees. They usually are most active and feed the most during May through September. Western Black Widows also follow habits of cannibalism, including their mates and their siblings. 

Western black widow spiders have a lifespan of about a year. They mature about 92 days after they hatch from the egg. Males live much shorter than females, with a lifespan of only about 30 days, and they mature 71 days after emerging from the sac. 


How to spot a Western black widow spider’s web?


The webs of western black widow spiders are very messy and irregular compared to the webs of other spiders. The webs are usually very close to the ground, and they are generally under something that can protect them, such as lawn furniture or woodpiles. The female black widows often hang out near the web, so you might see the spider and the web together. 


How to Deal with a Spider Bite


Spider bites can be severe from a venomous spider because they can cause disease and other harm. For example, if you think you have been bitten by a venomous spider, you need to visit a clinic or hospital right away because the sooner you receive the treatment, the less damage your body will have from the bite. 


What does a spider bite look like?


Spider bites often look like any other bug bite. It can be a red and inflamed bump on the skin, and sometimes they itch, but not always. If you have been bit by a nonvenomous spider, the bites will cause a bump that eventually goes away and heals on its own. 

Venomous spider bites can also be a small white blister with a red ring around them. It might even look like a bull’s eye. The skin in the middle of the bite might turn blue or purple, turning into an open sore. Bites from a venomous spider will also continue to get bigger and bigger rather than shrinking and healing. Its open sore can get bigger 10 days after getting the bite. 

If the bite is from a venomous spider, you might also experience many other symptoms including:

● Itchy skin rash that spreads

● Sweating and fever 

● Muscle cramps and muscle stiffness 

● Nausea and vomiting 

● Increased saliva production 

● Headache 

● Swollen eyes 

● Difficulty breathing 


How dangerous is a spider bite?


Spider bites are usually pretty harmless because there are not many spiders that are venomous out there. The good news is that all spiders usually only bite when they feel threatened. So, if you leave the spider alone and don’t go near them, you have a low chance of being bitten. 

However, venomous spider bites can be very dangerous and even life-threatening. They can cause severe reactions, including difficulty breathing and severe headaches. They can also cause the tissue around the bite to decay, which can be very serious. If you think a venomous spider bit you, seek medical care right away. 


Ways to Treat a Spider Bite


If you have been bitten by a venomous spider or aren’t sure what kind of spider you got bit by, head to the nearest medical center to check and make sure the bit is not severe. You should also seek medical care if you have any symptoms of an allergic reaction or if the bite is becoming bigger instead of healing and becoming smaller. 

If you don’t think a venomous spider bit you and do not have any swelling or fever, you can treat the bite at home. Make sure to clean the wound with mild soap and water. You can also apply antibiotic ointment three times a day to ensure the bite does not get infected. 

If the bite is painful, you can also apply a cool compress for 15 minutes to the bite. Make sure also to elevate the affected area if you can. If you are in pain, you can take over-the-counter pain relievers. If the wound is itchy, you can also take over-the-counter allergy medicine. 



While spiders can be poisonous, many don’t want to hurt or even interact with humans. You can also apply these home remedies to repel some of the spiders. But if you are having trouble with getting rid of these common California spiders, it is best to call in the pest control.