Venomous snakes and spiders in California

California's venomous snakes are seven rattlesnake species. Together they account for 9,109 licensed records; the western rattlesnake alone has 57% of them, and the least recorded, the western diamondback rattlesnake, has 169.

Two widow species (Western black widow: 1,236 records, Brown widow: 776 records) and one recluse species (Desert recluse: 40 records) are on the California list. Widow bites cause muscle pain and cramps; recluse bites can cause a slow-healing wound. Both are rare and seldom fatal.

Yes. 47 scorpion species are recorded in California, from 2,331 licensed records, the five most recorded: California forest scorpion (832 records), California common scorpion (190 records), Sawfinger scorpion (137 records), California swollenstinger scorpion (109 records), Paravaejovis puritanus (106 records). Every scorpion has venom; only the Arizona bark scorpion's sting is medically significant, and it is on the California list.

Beyond the main list, two scorpion species are known from California by only 3 to 9 records each. Some are genuine rarities at the edge of their range; others may be strays, released pets or old misidentifications, so treat them as unconfirmed.

These eight account for 66% of all licensed snake records in California; the most recorded, the western terrestrial garter snake, alone for 30%.

These eight account for 24% of all licensed spider records in California; the most recorded, the bold jumper, alone for 5%.

Observation records of venomous snakes in California run mostly March through September, peaking in April with 20% of them. Winter (December to February) holds 3% of the records.

Observation records of spiders in California run through most of the year, peaking in April with 12% of them. Winter (December to February) holds 14% of the records.

Observation records of scorpions in California run through most of the year, peaking in May with 13% of them. Winter (December to February) holds 16% of the records.

San Diego County has the most records of venomous snakes in California, 2,396, most of them of the western rattlesnake. Riverside County and San Bernardino County follow.

San Diego County leads with 9,077 records (12%), followed by Lassen County and Shasta County; the top five counties hold 43% of the total. 58 of California's 58 counties have at least one licensed snake record.

California counties with their own page: Alameda County, Butte County, Contra Costa County, Del Norte County, El Dorado County, Fresno County, Humboldt County, Imperial County, Inyo County, Kern County, Lake County, Lassen County, Los Angeles County, Marin County, Mariposa County, Mendocino County, Modoc County, Mono County, Monterey County, Napa County, Nevada County, Orange County, Plumas County, Riverside County, Sacramento County, San Benito County, San Bernardino County, San Diego County, San Francisco County, San Joaquin County, San Luis Obispo County, San Mateo County, Santa Barbara County, Santa Clara County, Santa Cruz County, Shasta County, Siskiyou County, Solano County, Sonoma County, Trinity County, Tulare County, Tuolumne County and Ventura County.

Yes. California has seven venomous snake species on its list, the kind people usually call poisonous: western rattlesnake, sidewinder, red diamond rattlesnake, Mohave rattlesnake, southwestern speckled rattlesnake, Panamint rattlesnake and western diamondback rattlesnake. Strictly, snakes are venomous (they inject venom), not poisonous (harmful to eat or touch).

Yes. Seven species are on the California list: the western rattlesnake, the sidewinder, the red diamond rattlesnake, the Mohave rattlesnake, the southwestern speckled rattlesnake, the Panamint rattlesnake and the western diamondback rattlesnake, with 9,109 licensed records between them. Most licensed records of the western rattlesnake come from San Diego County, Los Angeles County and Santa Clara County.

No. GBIF holds no copperhead record for California under any license.

No. GBIF holds no cottonmouth record for California under any license.

Not on our list: GBIF holds 3 coral snake records of any license in California (Sonoran coralsnake 3), fewer than 10 of any one species; such records can be genuine rarities, strays, transported animals or misidentifications. Treat any snake that looks like a coral snake as venomous.

California has 5,224 licensed records of the western rattlesnake, which ranks the state 1st of the 9 states where it reaches our threshold. Its observation records in California run mostly March through September, peaking in May; most licensed records come from San Diego County, Los Angeles County and Santa Clara County. Range in other states and photos: Western rattlesnake profile.

California has 1,923 licensed records of the sidewinder, which ranks the state 1st of the 4 states where it reaches our threshold. Its observation records in California run mostly March through October, peaking in April; most licensed records come from Riverside County, San Bernardino County and San Diego County. Range in other states and photos: Sidewinder profile.

California has 916 licensed records of the red diamond rattlesnake, the only state where it reaches our listing threshold. Its observation records in California run mostly March through September, peaking in April; most licensed records come from San Diego County, Riverside County and Orange County. Range in other states and photos: Red diamond rattlesnake profile.

California has 430 licensed records of the Mohave rattlesnake, which ranks the state 2nd of the 6 states where it reaches our threshold. Its observation records in California run mostly March through September, peaking in April; most licensed records come from San Bernardino County, Kern County and Los Angeles County. Range in other states and photos: Mohave rattlesnake profile.

California has 269 licensed records of the southwestern speckled rattlesnake, which ranks the state 1st of the 4 states where it reaches our threshold. Its observation records in California run mostly March through September, peaking in May; most licensed records come from Riverside County, San Diego County and San Bernardino County. Range in other states and photos: Southwestern speckled rattlesnake profile.

California has 178 licensed records of the Panamint rattlesnake, which ranks the state 1st of the 2 states where it reaches our threshold. Its observation records in California run mostly April through August, peaking in May; most licensed records come from Inyo County, Mono County and San Bernardino County. Range in other states and photos: Panamint rattlesnake profile.

California has 169 licensed records of the western diamondback rattlesnake, which ranks the state 5th of the 7 states where it reaches our threshold. Most of its licensed records in California come from Riverside County, Imperial County and San Bernardino County. Range in other states and photos: Western diamondback rattlesnake profile.

Many snakes and spiders taken for venomous ones are harmless species with a similar look. These are the usual confusions, with each species' licensed records in California.

No copperheads reach the California list, and GBIF holds no copperhead record for California under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: corn snake (5).

No cottonmouths reach the California list, and GBIF holds no cottonmouth record for California under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: southern watersnake (30).

Rattlesnakes: 9,109 licensed records in California. Harmless species often taken for them are also on the state list: gopher snake (7,188). It has 7,188 licensed records, and the two sides are recorded about equally.

Coral snakes are not on the California list, but they are recorded in California three times (records of any license: Sonoran coralsnake 3): treat any snake like this as venomous until identified. Harmless species often taken for them in the state: long-nosed snake (1,014) and California mountain kingsnake (533).

Widow spiders: 2,012 licensed records in California. Harmless species often taken for them are also on the state list: false black widow (1,201), common house spider (197) and triangulate bud spider (72). Together they have 1,470 licensed records, and the two sides are recorded about equally.

Recluse spiders: 40 licensed records in California. Harmless species often taken for them are also on the state list: longbodied cellar spider (688) and spitting spider (12). Together they have 700 licensed records, and the lookalikes are recorded 18 times as often.

By count of venomous snake species, California ranks 5th of 50 states, level with Florida and Georgia. Nationally, Arizona leads with 14 species; five list none.

Of the three states bordering California, Arizona lists more venomous snake species (California: 7 species; Arizona 14, Nevada 6, Oregon 1).

Venomous snakes listed next door but not in California: the Arizona black rattlesnake (Arizona); the black-tailed rattlesnake (Arizona); the prairie rattlesnake (Arizona); the ridge-nosed rattlesnake (Arizona); the rock rattlesnake (Arizona); the Sonoran coralsnake (Arizona). Listed next door and recorded in California too, but too few times to list (records of any license): the tiger rattlesnake, recorded here only one time (listed in Arizona). Listed in California but in none of its neighbors: the red diamond rattlesnake. The most widely shared is the western rattlesnake, listed in all three bordering states.

Yes. Two widow species are on the California list: the western black widow (1,236 records) and the brown widow (776 records).

Not on our list: GBIF holds 1 brown recluse record of any license in California (brown recluse 1), fewer than 10 of any one species; such records can be genuine rarities, strays, transported animals or misidentifications. Treat any spider that looks like a recluse as venomous. Other recluse species on the California list: the desert recluse.

California has 1,236 licensed records of the western black widow, which ranks the state 1st of the 18 states where it reaches our threshold. Its observation records in California run through most of the year, peaking in October; most licensed records come from Los Angeles County, San Diego County and Napa County. Range in other states and photos: Western black widow profile.

California has 776 licensed records of the brown widow, which ranks the state 1st of the 11 states where it reaches our threshold. Its observation records in California run through most of the year, peaking in August; most licensed records come from Los Angeles County, San Diego County and Orange County. Range in other states and photos: Brown widow profile.

California has 40 licensed records of the desert recluse, which ranks the state 1st of the 3 states where it reaches our threshold. Its observation records in California run mostly February through October, peaking in May; most licensed records come from San Bernardino County, Kern County and San Diego County. Range in other states and photos: Desert recluse profile.