Snakes and spiders in Alameda County, California
Alameda County has 16 snake and 49 spider species on record, from 1,639 licensed snake and 1,245 spider records. Venomous species here: the western rattlesnake and the western black widow.
Are there venomous snakes or spiders in Alameda County?
Yes. The western rattlesnake: 218 licensed records, 4% of all California records of it. The western black widow: 23 licensed records, 2% of all California records of it.
What snakes are in Alameda County?
In all, 16 snake species are on the Alameda County list. The most recorded are the gopher snake (392), the western rattlesnake (218) and the aquatic garter snake (204).
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Gopher snake Pituophis catenifer | 392 | 5% |
| 2 | Western rattlesnake venomous Crotalus oreganus | 218 | 4% |
| 3 | Aquatic garter snake Thamnophis atratus | 204 | 5% |
| 4 | Western terrestrial garter snake Thamnophis elegans | 189 | 1% |
| 5 | Sharp-tailed snake Contia tenuis | 131 | 15% |
| 6 | Ring-necked snake Diadophis punctatus | 109 | 6% |
| 7 | California kingsnake Lampropeltis californiae | 91 | 3% |
| 8 | Eastern racer Coluber constrictor | 80 | 6% |
| 9 | Striped racer Masticophis lateralis | 42 | 3% |
| 10 | Western aquatic garter snake Thamnophis couchii | 35 | 1% |
| 11 | Long-nosed snake Rhinocheilus lecontei | 23 | 2% |
| 12 | Northern rubber boa Charina bottae | 23 | 4% |
| 13 | Glossy snake Arizona elegans | 20 | 1% |
| 14 | Western black-headed snake Tantilla planiceps | 18 | 9% |
| 15 | Common garter snake Thamnophis sirtalis | 11 | 0% |
| 16 | Coast nightsnake Hypsiglena ochrorhynchus | 10 | 4% |
When are snakes out in Alameda County?
Observation records of snakes in Alameda County run mostly March through October, peaking in May with 25% of them, the same peak as California as a whole.
What spiders are in Alameda County?
In all, 49 spider species are on the Alameda County list. The most recorded are Steatoda nobilis (138), the Johnson jumper (128) and the garden spider (126). Alameda County holds more than half of all California records of Heliophanus apiatus.
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Steatoda nobilis | 138 | 7% |
| 2 | Johnson jumper Phidippus johnsoni | 128 | 14% |
| 3 | Garden spider Araneus diadematus | 126 | 28% |
| 4 | Buttonhook leafbeetle jumping spider Sassacus vitis | 56 | 7% |
| 5 | Gray house spider Badumna longinqua | 55 | 16% |
| 6 | False black widow Steatoda grossa | 44 | 4% |
| 7 | Zoropsid spider Zoropsis spinimana | 44 | 39% |
| 8 | Heliophanus apiatus | 40 | 73% |
| 9 | Longbodied cellar spider Pholcus phalangioides | 34 | 5% |
| 10 | Bold jumper Phidippus audax | 32 | 1% |
| 11 | Koch's wolf spider Alopecosa kochi | 30 | 3% |
| 12 | Marbled cellar spider Holocnemus pluchei | 27 | 3% |
| 13 | Dysdera crocata | 25 | 4% |
| 14 | Mouse spider Scotophaeus blackwalli | 24 | 9% |
| 15 | Bay Area blonde Aphonopelma iodius | 23 | 7% |
| 16 | Western black widow venomous Latrodectus hesperus | 23 | 2% |
| 17 | Half-edged wall jumping spider Menemerus semilimbatus | 22 | 1% |
| 18 | Zygiella x-notata | 22 | 28% |
| 19 | California turret spider Atypoides riversi | 20 | 5% |
| 20 | Habronattus pyrrithrix | 20 | 2% |
| 21 | California funnel-web spider Calisoga longitarsis | 16 | 10% |
| 22 | Banded garden spider Argiope trifasciata | 14 | 5% |
| 23 | Colonus hesperus | 12 | 2% |
| 24 | Western spotted orbweaver Neoscona oaxacensis | 12 | 2% |
| 25 | Western lynx spider Oxyopes scalaris | 11 | 1% |
| 26 | Cyclosa turbinata | 9 | 6% |
| 27 | Zebra spider Salticus scenicus | 9 | 3% |
| 28 | Cone-shaped orbweaver Cyclosa conica | 7 | 7% |
| 29 | Habronattus klauseri | 7 | 21% |
| 30 | Flatmesh weaver Oecobius navus | 6 | 2% |
| 31 | Sierra dome spider Neriene litigiosa | 6 | 7% |
| 32 | Sixspotted orbweaver Araniella displicata | 6 | 3% |
| 33 | Common candy-striped spider Enoplognatha ovata | 5 | 45% |
| 34 | Mexigonus minutus | 5 | 6% |
| 35 | Phanias harfordi | 5 | 13% |
| 36 | Spotted orbweaver Neoscona crucifera | 5 | 1% |
| 37 | Diaea livens | 4 | 9% |
| 38 | McCook's split wolf spider Schizocosa mccooki | 4 | 2% |
| 39 | Neriene digna | 4 | 7% |
| 40 | Shoreline wolf spider Arctosa littoralis | 4 | 5% |
| 41 | Castianeira thalia | 3 | 8% |
| 42 | Pelegrina aeneola | 3 | 3% |
| 43 | Striped lynx spider Oxyopes salticus | 3 | 0% |
| 44 | Black-and-yellow argiope Argiope aurantia | 2 | 1% |
| 45 | Goldenrod crab spider Misumena vatia | 2 | 1% |
| 46 | Hairy tufted jumping spider Phidippus comatus | 2 | 2% |
| 47 | Metaphidippus manni | 2 | 2% |
| 48 | Green lynx spider Peucetia viridans | 1 | 0% |
| 49 | Northern yellow sac spider Cheiracanthium mildei | — | — |
When are spiders out in Alameda County?
Observation records of spiders in Alameda County run through most of the year, peaking in September with 13% of them; across California the peak is April.
What stands out in Alameda County
Species for which Alameda County holds a large share of all California records: Heliophanus apiatus, 73% (40 of 55); the zoropsid spider, 39% (44 of 114); Zygiella x-notata, 28% (22 of 78); the garden spider, 28% (126 of 457); the gray house spider, 16% (55 of 342).
Common in California, not on the Alameda County list
Among the snakes most recorded across California, these do not reach the county list: the sidewinder (1,923 statewide), the two-striped garter snake (1,620 statewide) and the western shovel-nosed snake (1,482 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Among the spiders most recorded across California, these do not reach the county list: the brown widow (776 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Harmless lookalikes in Alameda County
Rattlesnakes are on the county list, and so are harmless species often taken for them: the gopher snake. Coral snakes are not on the California list, but GBIF holds 3 coral snake records of any license in California (Sonoran coralsnake 3): treat any snake like this as venomous until identified. Harmless species often taken for them here: the long-nosed snake. Widow spiders are on the county list, and so are harmless species often taken for them: the false black widow. No recluse spiders reach the county list, but the desert recluse is on the California list: treat any spider like it as venomous until identified. Harmless species often taken for them here: the longbodied cellar spider.
Alameda County among California counties
By licensed snake records Alameda County ranks 12th of 58 California counties with any.
Other California counties with their own page: San Diego County, Lassen County, Shasta County, Riverside County, San Bernardino County, Humboldt County, Sonoma County and San Mateo County.
The whole state: venomous species in California, all snakes, all spiders.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.