California is the third-largest and one of the most diverse States in the United States. From the dry and arid landscapes in Southwestern California to coastal landscapes around the largest cities of the state to cooler and higher-altitude areas to the north. Due to this natural diversity, the state of California is home to more spider species than any other state in the U.S.
Of the 67 spider families with thousands of species, 59 families are found in California. Fortunately, almost all spiders that you can find in California are harmless for humans or pets – the few potentially dangerous species are rare and relatively easy to identify.
Now available: The USAspiders California spider identification book – available as an ebook here or as a printed paperback on Amazon. Written in a simple, non-scientific language with illustrations, tips & tricks and identification sheets.
California poisonous spiders
Almost all spiders in the world are venomous. However, their main prey are insects and other small animals – therefore, the venom of most spiders is not strong enough to cause any serious effects on humans or larger pets. Usually, a spider bite leads to symptoms comparable to a bee sting with mild pain, local swelling and redness.
In California, two types of spiders are considered medically significant. That means that their bites can lead to symptoms that require medical attention. These spiders are western black widows (Loxosceles hesperus) and recluse spiders.
Western black widows can come in a range of colors since they change their appearance as the reach maturity. Please note that only the adult female black widow is able to deliver medically significant bites – bites of juvenile and male widows may be uncomfortable but do usually not require medical attention. The adult female western black widow has a completely black and shiny body with an orange or red hourglass-shape at the bottom.
To learn more about the western black widow, follow the link below.
Latrodectus hesperus, the Western black widow spider is one of the few medically significant venomous spiders in the United States. As its common name suggests, it can be found in the Western States of the US as well as in Canada. Description of the Western Black Widow The larger female Western black widow looks very similar to the Northern black widow and the Southern black widow female. The best indicator ...Read More
Even though this spider has a very bad reputation and sightings are commonly reported, recluse spiders are very rare in California. The desert recluse, as its name says, lives in mostly uninhabited locations, and the Chilean recluse is only found in a few limited areas of Southern California. And hasn’t been able to establish sizeable populations. The most common recluse spider in the United States, the brown recluse, is not found in California.
The brown recluse, loxosceles reclusa, is one of the more dangerous spiders indigenous in the United States. While usually not life-threatening, a brown recluse bite might lead to severe skin damage. This page gives an overview of how to identify a brown recluse and in which states in the US it appears. The brown recluse compared to the size of a penny. Brown Recluse Description The brown recluse spider is ...Read More
Are hobo spiders found in California?
Hobo spiders (Eratigena agrestis) are found in the Pacific Northwest of North America. They are occasionally found in California’s far north. However, despite their bad reputation, to date, no recorded verifications by a certified arachnologist (spider expert) have been made.
The hobo spider has sparked fears throughout the U.S. because its bites were thought to lead to cause necrosis (rotting flesh), like some rare dramatic bites of brown recluse spiders. However, it has been proven that hobo spiders are not dangerous for humans and that their bad reputation came from wrongly interpreted lab results in the 1980ies.
Eratigena agrestis, commonly know as the hobo spider, is a funnel web spider that can be found in the Pacific Northwest. In the 90ies, the hobo spider has been listed as a medically important species. However, over the last 30 years, no actual evidence has been found that the spider is actually dangerous for humans. In 2017, the CDC removed the hobo spider from its list of dangerous spiders. Hobo ...Read More
Big brown spiders in California
Around one in three Americans is suffering from arachnophobia – the fear of spiders. The bigger, the greater the fear. Maybe we can comfort you in telling you that none of the big brown or black spiders found in the sunshine state are medically significant.
Here is a quick overview of the most common brown spiders you may find in or around your home. Most of the ID requests we receive are from wolf spiders.
Aphonopelma chalcodes is a large tarantula that is commonly known as the western desert tarantula, Arizona blond tarantula, or Mexican ...Read More
Heteropoda venatoria, the pantropical huntsman spider, is a member of the running crab spider family Sparassidae. They are commonly found ...Read More
Aphonopelma eutylenum, the California ebony tarantula is a large spider that can be found in California and its surrounding states ...Read More
Olios Giganteus, the giant crab spider, belongs to the family of Sparassidae spiders, which are commonly called huntsman spiders. As ...Read More
Eratigena agrestis, commonly know as the hobo spider, is a funnel web spider that can be found in the Pacific ...Read More
Ummidia is a genus of spiders that can be found around the world. Among other genus, they are commonly called ...Read More
Kukulcania hibernalis, the Southern House Spider is a large brown spider that can be found throughout the Southern United States, ...Read More
Philodromus, commonly called running crab spider, is a genus of crab spiders. Various species can be found throughout the entire ...Read More
The Lycosidae, commonly called wolf spiders are a family of hunter spiders found throughout the United States and the rest ...Read More
Agelenopsis, American grass spiders, are a genus of spiders that can be found around the world and in every US ...Read More
As the name suggests, the fishing spider is a semi-aquatic genus of spiders that are found all over the world ...Read More
Common house spiders in California
The term “house spider” is not a scientific definition or classification of spiders. Several spiders that are commonly found in buildings are referred to as such. Some of the most common California house spiders are cobweb spiders, also called false widow spiders (Steatoda) or cellar spiders. These spiders build erratic tangle webs in corners, dark cupboards or basements to catch small insects.
The list below introduces you to some more common spiders that are commonly observed inside people’s home.
Known in the United Kingdom as the Noble False Widow, Steatoda Nobilis is a species of spider in the genus ...Read More
The bowl and doily spiders, known as Frontinella pyramitela, are a small species of spiders that belong to the family ...Read More
Metaltella simoni is a spider species that is commonly often referred to as hacklemesh weaver. This may lead to confusion ...Read More
The gray house spider, Badmuna longinqua, is a medium sized black and gray spider originally native to Australia. It has ...Read More
The Steatoda grossa, commonly called the false black widow spider or cupboard spider can be found throughout the United States ...Read More
Latrodectus hesperus, the Western black widow spider is one of the few medically significant venomous spiders in the United States ...Read More
Latrodectus geometricus, commonly called the brown widow spider, is one of the most common widow spiders that can be found ...Read More
The spitting spider, scientifically called Scytodaes thoracica, is a fascinating type of hunting spider that captures and paralyzes its prey ...Read More
Herpyllus ecclesiasticus, The Eastern parson spider is one of the most commonly encountered hunter spiders in the United States. The ...Read More
Cheiracanthium mildei, the northern yellow sac spider is one of the most common spiders in Northeastern America. However, it can ...Read More
The Steatoda triangulosa, commonly called the triangulate cobweb spider is a brown-black spider found throughout the US. It has an ...Read More
The Steatoda bipunctata, commonly called rabbit hutch spider is a black spider found throughout the United States. It comes from ...Read More
As the name suggests, the Dysdera crocata, or commonly called woodlouse spider, primarily preys on woodlice. The spider can be ...Read More
As strange as it sounds, the Pholcidae, or Cellar Spider is one of the most misunderstood spiders in the world ...Read More
Parasteatoda tepidariorum, or the common house spider can be found in every US state. The spider is also distributed throughout ...Read More
If you head out into your backyard, you will encounter completely different spiders. They often spin large circular webs to catch flying insects. These spiders are called orb-weavers. Even though their webs can sometimes become a nuisance, these spiders are not dangerous and they catch annoying flying insects and pests. Some of the most common species, like the black and yellow garden spider can be colorful and fun to identify. Check our the most common CA orbweavers here:
The arrow-head spider, Verrucosa arenata, is an orb-weaver spider found throughout the United States. Its common name arrowhead spider or ...Read More
The silver garden spider, Argiope argentata, is a common orb weaver in the warm and humid regions in the Southern ...Read More
The western spotted orb weaver, Neoscona oaxacensis, is a large orb weaving spider found in the Southwestern United States and ...Read More
The missing sector orb weaver, Zygiella x-notata, is a common spider species found throughout Europe and the United States. The ...Read More
The tropical orb weaver, Eriophora ravilla, is a harmless orb weaver spider found throughout the tropical areas of the Americas ...Read More
The spinybacked orbweaver is a small harmless spider with six characteristic spines along the back of its abdomen. It can ...Read More
Acanthepeira stellata, commonly called the starbellied orb weaver, is one of the most remarkable and memorable orb weaver spiders. Its ...Read More
Neoscona arabesca, commonly known as the arabesque orbweaver, is one of the most common orbweaver species that can be found ...Read More
Trichonephila clavipes, commonly called banana spider or golden-silk orb weaver is a unique orb weaver species due to its shape ...Read More
Araneus trifolium, the shamrock spider, is a widely distributed orb weaver that can come in various colors, mostly beige or ...Read More
The Pachygnatha is technically part of the Orb Weaver family. However, it does not spin a web and is a ...Read More
Larinioides Cornutus, commonly known as the furrow spider, is an orb weaver species that can be found throughout the Northern ...Read More
The Araneus Gemmoides is an orb weaver species that occurs in the Western United States. It is also known under ...Read More
The Argiope trifasciata or Banded Garden Spider is one of the most common species of the Argiope orb weaving spider ...Read More
The Argiope Aurantia or black and yellow garden spider appears in every US state and in many other countries around ...Read More
Araneus diadematus, also called the European garden spider or the cross spider is an orb weaver spider with an iconic ...Read More
Salticidae, or jumping spiders, are one of the largest spider families with over 600 identified genera and over 6,000 described species. As their common name suggests, these spiders have the ability to make huge sudden jumps – of distances up to 45 times their own body size.
The red-backed jumping spider, Phidippus johnsoni, is found throughout the Western United States and Canada. The spider has a black ...Read More
Phidippus regius, the regal jumping spider, is one of the largest species of the jumping spiders of the Phidippus genera ...Read More
Salticus scenicus, the zebra spider, is a jumping spider that can be found in the entire Northern Hemisphere. As its ...Read More
Menemerus bivittatus, commonly called the gray wall jumper or the gray jumping spider, is a jumping spider that can be ...Read More
Phidippus audax, commonly known as the daring jumping spider is a jumping spider found throughout the USA. As their name ...Read More
Other common California spiders
The misumena, commonly called flower crab spider, is a genus of spiders that hunt their prey in or around flowers ...Read More
Spiders of the Xysticus genus, also called ground crab spiders are a rather indistinct species. As all crab spiders, they ...Read More
Spiders of the genus Clubiona, commonly called leaf-curling sac spiders, can be found throughout the world and in every US ...Read More
Castianeira descripta, more commonly know as the red-spotted ant mimic spider gets its common name from the similar look and ...Read More
Kukulcania hibernalis, the Southern House Spider is a large brown spider that can be found throughout the Southern United States, ...Read More
Even though Xysticus funestus has a dangerously-sounding common name, the deadly ground crab spider, it is of absolutely no concern ...Read More
Hibana are a genus of spiders commonly referred to as ghost spiders. They are common throughout South and Central America, ...Read More
Peucetia viridans, commonly known as the green lynx spider, is a large bright green spider found on many kinds of ...Read More
California spider identification
If you’ve discovered a spider in California that is not listed here or that you cannot identify, go to our spider identification page for help. We created a spider identification tool that allows you to answer a few questions. The identification tool will generate a list of possible matches of what type of spider you encountered. If that doesn’t help you identify your California spider, you can instead take a picture of it and upload it to that page. Our spider specialists will do their utmost to identify the spider and contact you as soon as they finally identify what spider you have encountered.
Do you want to learn more about spiders in California? Check out our California spider identification guide ebook or the paperback version on Amazon – the best California spider identification book out there!