Snakes and spiders in Tuolumne County, California
Tuolumne County, home of Sonora, has 12 snake and 14 spider species on record, from 503 licensed snake and 295 spider records. Venomous species here: the western rattlesnake and the western black widow.
Are there venomous snakes or spiders in Tuolumne County?
Yes. The western rattlesnake: 47 licensed records, 1% of all California records of it. The western black widow: 8 licensed records, 1% of all California records of it.
What snakes are in Tuolumne County?
In all, 12 snake species are on the Tuolumne County list. The most recorded are the western terrestrial garter snake (197), the western aquatic garter snake (75) and the western rattlesnake (47).
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Western terrestrial garter snake Thamnophis elegans | 197 | 1% |
| 2 | Western aquatic garter snake Thamnophis couchii | 75 | 2% |
| 3 | Western rattlesnake venomous Crotalus oreganus | 47 | 1% |
| 4 | Northern rubber boa Charina bottae | 42 | 7% |
| 5 | Gopher snake Pituophis catenifer | 29 | 0% |
| 6 | California mountain kingsnake Lampropeltis zonata | 23 | 4% |
| 7 | Common garter snake Thamnophis sirtalis | 14 | 0% |
| 8 | Eastern racer Coluber constrictor | 13 | 1% |
| 9 | Sharp-tailed snake Contia tenuis | 12 | 1% |
| 10 | Ring-necked snake Diadophis punctatus | 10 | 1% |
| 11 | Striped racer Masticophis lateralis | 10 | 1% |
| 12 | California kingsnake Lampropeltis californiae | 3 | 0% |
When are snakes out in Tuolumne County?
Observation records of snakes in Tuolumne County run mostly April through September, peaking in May with 30% of them, the same peak as California as a whole.
What spiders are in Tuolumne County?
In all, 14 spider species are on the Tuolumne County list. The most recorded are Habronattus americanus (177), the marbled cellar spider (14) and Colonus hesperus (11). Tuolumne County holds more than half of all California records of Habronattus americanus.
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Habronattus americanus | 177 | 56% |
| 2 | Marbled cellar spider Holocnemus pluchei | 14 | 2% |
| 3 | Colonus hesperus | 11 | 1% |
| 4 | Koch's wolf spider Alopecosa kochi | 11 | 1% |
| 5 | Western black widow venomous Latrodectus hesperus | 8 | 1% |
| 6 | California flattened jumping spider Platycryptus californicus | 6 | 5% |
| 7 | Half-edged wall jumping spider Menemerus semilimbatus | 3 | 0% |
| 8 | Johnny Cash tarantula Aphonopelma johnnycashi | 2 | 6% |
| 9 | Johnson jumper Phidippus johnsoni | 2 | 0% |
| 10 | Western lynx spider Oxyopes scalaris | 2 | 0% |
| 11 | Western parson spider Herpyllus propinquus | 2 | 1% |
| 12 | Sixspotted orbweaver Araniella displicata | 1 | 0% |
| 13 | California funnel-web spider Calisoga longitarsis | — | — |
| 14 | Giant crab spider Olios giganteus | — | — |
When are spiders out in Tuolumne County?
Observation records of spiders in Tuolumne County run mostly March through November, peaking in June with 23% of them; across California the peak is April.
What stands out in Tuolumne County
Species for which Tuolumne County holds a large share of all California records: Habronattus americanus, 56% (177 of 316).
Common in California, not on the Tuolumne County list
Among the snakes most recorded across California, these do not reach the county list: the aquatic garter snake (3,727 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), Steatoda nobilis (1,914 statewide), the false black widow (1,201 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 Tuolumne 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 California mountain kingsnake.
Tuolumne County among California counties
By licensed snake records Tuolumne County ranks 32nd 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.