10 Brown Spiders Found in California

Quick Take

• Most Californians fear the wrong spider entirely. The one they're actually worried about isn't even here, but three others that are rarely discussed may be. See which spiders are actually here →
• One brown spider in California has venom that lab studies call more potent than a black widow's, yet experts don't consider its bite medically dangerous. Here's the twist. Unpack the venom paradox →
• A spider with a medically significant, flesh-damaging bite has quietly lived in one California county since the 1930s, a fact that most residents have no idea about. Meet the hidden resident →
• The spider everyone calls deadly because of its bite has been carrying a myth far longer than it carries its own babies, and the truth turns out to be stranger still. Explore the debunked myth →

There are over 50,000 known species of spiders worldwide, with approximately 900 different species found in California. While there is no official scientific percentage for how many spiders are brown, experts generally agree that the vast majority of all spider species are primarily brown, tan, or gray. Shades of brown and dull earthy tones allow them to blend into soil, leaf litter, tree trunks, and rocks to hide from predators. Continue reading to learn about 10 common brown spiders in California.

Are There Brown Recluse Spiders in California?

Despite what you may have heard, brown recluse spiders (Loxosceles reclusa) are not native to California, and there are no populations of brown recluse spiders in California. Brown recluses are venomous spiders whose bites can cause necrotizing wounds that may require medical intervention to heal. Although most of the brown spiders in California are harmless to humans, there are three that can be medically significant to humans: the desert recluse, Chilean recluse, and brown widow.

Desert Recluse

The desert recluse (Loxosceles deserta) is native to the arid regions of Southwestern North America. Typically lighter in color than its relative, the brown recluse, the desert recluse is pale tan or sandy colored across its body and slender legs, often featuring a subtle, darker violin-shaped marking on its cephalothorax and a uniformly colored abdomen.

Adult desert recluses have leg spans of between 1.5 and 2 inches. In California, the species is distributed primarily throughout the Southeastern desert regions, notably within the Mojave Desert and Sonoran Desert. Its bite is considered medically significant to humans because its venom contains an enzyme that can cause necrotic skin lesions and localized tissue damage. However, bites are exceedingly rare due to the spider’s non-aggressive nature and preference for sparsely populated, undisturbed wild habitats.

Chilean Recluse

The Chilean recluse (Loxosceles laeta) is one of the largest members of the recluse family, with a body length of 8–15 mm and a leg span that can reach up to 40 mm (roughly 1.57 inches). These spiders have a tan to reddish-brown cephalothorax that is often marked by a darker, violin-shaped pattern.

Outside its native South American range, isolated non-native populations have been documented in California within parts of Los Angeles County. The Chilean recluse was first documented in Los Angeles County in the late 1930s, though the exact means by which it arrived remains unclear. Where present, the Chilean recluse appears to be confined to a very limited area in Los Angeles County and has not become widespread in homes or commercial buildings across the state. The bite of the Chilean recluse is definitely medically significant to humans, as they have the same necrotizing venom as other recluse spiders.

Brown Widow

Brown widows (Latrodectus geometricus) are smaller than black widows. Adult female brown widows have leg spans of 1.5 to 2 inches, while adult male brown widows are smaller, with leg spans of 0.98 to 1.38 inches.

Brown widows are not aggressive, but they will bite if threatened or startled. Some laboratory studies suggest that brown widow venom may be more potent than that of the Southern black widow (Latrodectus mactans), but this is debated and not universally accepted among toxicologists. Brown widows are also smaller than black widows and inject only a fraction of the venom when they bite, which renders their bite medically insignificant to humans.

Stealthy Ground Spider

The stealthy ground spider (Gnaphosidae) is a wandering hunter characterized by a leg span of up to 1.5 inches. These spiders are dull gray-brown to pale tan, often featuring distinctive dark longitudinal stripes or pale markings along the abdomen. In California, stealthy ground spiders are widely distributed across the state, where they dwell under stones, leaf litter, and bark.

Stealthy ground spiders can occasionally wander into human structures like basements or attics. Their bite is not medically significant to humans. Their venom is mild, typically resulting in nothing more than minor, temporary localized pain or redness comparable to a bee sting.

Wolf Spider

Wolf spiders (Lycosidae) have a total of eight eyes, including two large, round black eyes on top of their heads, with a row of four small eyes below and two medium-sized eyes above. With more than 2000 separate species, wolf spiders range in size from .4 – 1.38 inches, with leg spans of 1 to 4 inches. California is home to more than 120 species of wolf spiders.

Mother wolf spiders carry their hatchlings on their backs for a few weeks until the young spiderlings are independent enough to disperse.

Grass Spider

The grass spider (Agelenopsis) is a ground-dwelling spider that spins sheet-like webs that lead to a tubular retreat. Grass spiders have leg spans ranging from 1 to 2 inches and are a brownish-yellow to tan color, marked with two dark longitudinal stripes along the cephalothorax and chevron patterns on the abdomen. A grass spider bite is not considered medically significant to humans, producing nothing more than localized pain, redness, and minor itching.

Orb Weaver

Orb weavers (Araneidae) are a diverse group of wheel-web-building arachnids. Members of this family typically have shiny, bulbous abdomens and long legs with an overall leg span that commonly ranges from 1 to 3 inches.

Their color varies widely. Nocturnal species often exhibit shades of tan, brown, or mottled gray, while diurnal species showcase striking patterns in yellow, orange, white, and black. California is home to hundreds of orb weaver species. While orb weavers do possess venom to immobilize small prey, their bite is not medically significant to humans.

Long-bodied Cellar Spider

The long-bodied cellar spider (Pholcus phalangioides) is easily identified by its elongated, cylindrical abdomen and its exceptionally long, threadlike legs spanning nearly 2 inches across. The long-bodied cellar spider is the most common non-native cellar spider species distributed statewide, but other cellar spider species are also present in California.

As their name suggests, cellar spiders primarily inhabit dark, sheltered indoor environments like basements, closets, and garages. Despite the persistent urban myth alleging that its bite is lethal, in truth, its bite is not considered medically significant to humans.

Tarantula

Tarantulas (Aphonopelma) represent all native tarantula species found in the United States. These spiders have large, hair-covered bodies, eight eyes, and adult leg spans ranging from about 4 to 6 inches or more. Their color is generally muted shades of tan, dark brown, and black.

In California, the genus is represented by between 10 and 15 recognized species. Tarantulas are distributed primarily across the Southern and Central parts of the state. Despite their formidable size and sharp chelicerae (fangs), a tarantula bite is not medically significant to humans. Their mild venom is adapted for immobilizing small invertebrate prey, and a bite usually produces pain, swelling, and redness comparable to a bee sting. However, their barbed urticating hairs (setae) can cause skin and eye irritation.