Snakes and spiders in Mendocino County, California
Mendocino County, home of Ukiah, has 12 snake and 19 spider species on record, from 1,127 licensed snake and 259 spider records. Venomous species here: the western rattlesnake and the western black widow.
Are there venomous snakes or spiders in Mendocino County?
Yes. The western rattlesnake: 62 licensed records, 1% of all California records of it. The western black widow: 3 licensed records, 0% of all California records of it.
What snakes are in Mendocino County?
In all, 12 snake species are on the Mendocino County list. The most recorded are the aquatic garter snake (502), the western terrestrial garter snake (203) and the common garter snake (107).
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Aquatic garter snake Thamnophis atratus | 502 | 13% |
| 2 | Western terrestrial garter snake Thamnophis elegans | 203 | 1% |
| 3 | Common garter snake Thamnophis sirtalis | 107 | 2% |
| 4 | Gopher snake Pituophis catenifer | 65 | 1% |
| 5 | Western rattlesnake venomous Crotalus oreganus | 62 | 1% |
| 6 | Ring-necked snake Diadophis punctatus | 43 | 2% |
| 7 | Eastern racer Coluber constrictor | 39 | 3% |
| 8 | California kingsnake Lampropeltis californiae | 29 | 1% |
| 9 | Sharp-tailed snake Contia tenuis | 25 | 3% |
| 10 | Forest sharp-tailed snake Contia longicauda | 17 | 15% |
| 11 | Northern rubber boa Charina bottae | 14 | 2% |
| 12 | Striped racer Masticophis lateralis | 8 | 1% |
When are snakes out in Mendocino County?
Observation records of snakes in Mendocino County run mostly April through September, peaking in April with 23% of them; across California the peak is May.
What spiders are in Mendocino County?
In all, 19 spider species are on the Mendocino County list. The most recorded are Colonus hesperus (10), the goldenrod crab spider (10) and the Koch's wolf spider (10).
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Colonus hesperus | 10 | 1% |
| 2 | Goldenrod crab spider Misumena vatia | 10 | 4% |
| 3 | Koch's wolf spider Alopecosa kochi | 10 | 1% |
| 4 | Western lynx spider Oxyopes scalaris | 8 | 1% |
| 5 | Western parson spider Herpyllus propinquus | 6 | 3% |
| 6 | California turret spider Atypoides riversi | 5 | 1% |
| 7 | Johnson jumper Phidippus johnsoni | 5 | 1% |
| 8 | Striped lynx spider Oxyopes salticus | 5 | 1% |
| 9 | California funnel-web spider Calisoga longitarsis | 4 | 2% |
| 10 | Marbled cellar spider Holocnemus pluchei | 4 | 0% |
| 11 | Gray house spider Badumna longinqua | 3 | 1% |
| 12 | Western black widow venomous Latrodectus hesperus | 3 | 0% |
| 13 | False black widow Steatoda grossa | 2 | 0% |
| 14 | Shamrock orbweaver Araneus trifolium | 2 | 4% |
| 15 | Steatoda nobilis | 2 | 0% |
| 16 | Banded garden spider Argiope trifasciata | 1 | 0% |
| 17 | Black-and-yellow argiope Argiope aurantia | 1 | 1% |
| 18 | Nordmann's orbweaver spider Araneus nordmanni | 1 | 11% |
| 19 | Half-edged wall jumping spider Menemerus semilimbatus | — | — |
When are spiders out in Mendocino County?
Observation records of spiders in Mendocino County run mostly March through November, peaking in June with 17% of them; across California the peak is April.
What stands out in Mendocino County
Species for which Mendocino County holds a large share of all California records: the forest sharp-tailed snake, 15% (17 of 110).
Common in California, not on the Mendocino County list
Among the snakes most recorded across California, these do not reach the county list: the western aquatic garter snake (3,716 statewide), the sidewinder (1,923 statewide), the two-striped garter snake (1,620 statewide), the western shovel-nosed snake (1,482 statewide) and the glossy snake (1,425 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 bold jumper (2,606 statewide), the buttonhook leafbeetle jumping spider (825 statewide), Habronattus pyrrithrix (800 statewide) and 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 Mendocino County
Rattlesnakes are on the county list, and so are harmless species often taken for them: the gopher snake. Widow spiders are on the county list, and so are harmless species often taken for them: the false black widow.
Mendocino County among California counties
By licensed snake records Mendocino County ranks 21st 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.