Snakes and spiders in Riverside County, California
Riverside County, home of Riverside, has 26 snake and 65 spider species on record, from 4,078 licensed snake and 1,160 spider records. Venomous species here: the sidewinder, the red diamond rattlesnake, the western rattlesnake, the southwestern speckled rattlesnake, the western diamondback rattlesnake, the western black widow, the brown widow and the desert recluse.
Are there venomous snakes or spiders in Riverside County?
Yes. The sidewinder: 537 licensed records, 28% of all California records of it. The red diamond rattlesnake: 235 licensed records, 26% of all California records of it. The western rattlesnake: 168 licensed records, 3% of all California records of it. The southwestern speckled rattlesnake: 110 licensed records, 41% of all California records of it. The western diamondback rattlesnake: 95 licensed records, 56% of all California records of it. The western black widow: 72 licensed records, 6% of all California records of it. The brown widow: 33 licensed records, 4% of all California records of it. The desert recluse: 4 licensed records, 10% of all California records of it.
What snakes are in Riverside County?
In all, 26 snake species are on the Riverside County list. The most recorded are the sidewinder (537), the western shovel-nosed snake (400) and the gopher snake (378). Riverside County holds more than half of all California records of the western diamondback rattlesnake.
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Sidewinder venomous Crotalus cerastes | 537 | 28% |
| 2 | Western shovel-nosed snake Sonora occipitalis | 400 | 27% |
| 3 | Gopher snake Pituophis catenifer | 378 | 5% |
| 4 | Spotted leaf-nosed snake Phyllorhynchus decurtatus | 313 | 25% |
| 5 | Glossy snake Arizona elegans | 296 | 21% |
| 6 | Coachwhip Masticophis flagellum | 252 | 22% |
| 7 | Red diamond rattlesnake venomous Crotalus ruber | 235 | 26% |
| 8 | Western rattlesnake venomous Crotalus oreganus | 168 | 3% |
| 9 | Long-nosed snake Rhinocheilus lecontei | 162 | 16% |
| 10 | California kingsnake Lampropeltis californiae | 149 | 6% |
| 11 | Southwestern speckled rattlesnake venomous Crotalus pyrrhus | 110 | 41% |
| 12 | Western patch-nosed snake Salvadora hexalepis | 108 | 18% |
| 13 | Rosy boa Lichanura trivirgata | 104 | 26% |
| 14 | Western diamondback rattlesnake venomous Crotalus atrox | 95 | 56% |
| 15 | Striped racer Masticophis lateralis | 86 | 7% |
| 16 | Two-striped garter snake Thamnophis hammondii | 84 | 5% |
| 17 | Western threadsnake Rena humilis | 81 | 12% |
| 18 | Northern three-lined boa Lichanura orcutti | 56 | 41% |
| 19 | Western aquatic garter snake Thamnophis couchii | 52 | 1% |
| 20 | Western black-headed snake Tantilla planiceps | 33 | 17% |
| 21 | California mountain kingsnake Lampropeltis zonata | 30 | 6% |
| 22 | Ring-necked snake Diadophis punctatus | 29 | 2% |
| 23 | Baja California lyre snake Trimorphodon lyrophanes | 16 | 9% |
| 24 | Desert nightsnake Hypsiglena chlorophaea | 12 | 11% |
| 25 | Coast nightsnake Hypsiglena ochrorhynchus | 11 | 5% |
| 26 | Brahminy blindsnake introduced Indotyphlops braminus | 2 | 4% |
When are snakes out in Riverside County?
Observation records of snakes in Riverside County run mostly March through October, peaking in May with 22% of them, the same peak as California as a whole.
What spiders are in Riverside County?
In all, 65 spider species are on the Riverside County list. The most recorded are the western black widow (72), the marbled cellar spider (38) and the brown widow (33). Riverside County holds more than half of all California records of Noonops coachella, Hogna antelucana and Dictis striatipes.
| # | Species | Records | Share of California records |
|---|---|---|---|
| 1 | Western black widow venomous Latrodectus hesperus | 72 | 6% |
| 2 | Marbled cellar spider Holocnemus pluchei | 38 | 5% |
| 3 | Brown widow venomous introduced Latrodectus geometricus | 33 | 4% |
| 4 | California ebony tarantula Aphonopelma eutylenum | 25 | 25% |
| 5 | Buttonhook leafbeetle jumping spider Sassacus vitis | 22 | 3% |
| 6 | Johnson jumper Phidippus johnsoni | 22 | 2% |
| 7 | Habronattus ustulatus | 21 | 32% |
| 8 | Koch's wolf spider Alopecosa kochi | 20 | 2% |
| 9 | Ribbon jumping spider Metacyrba taeniola | 20 | 8% |
| 10 | Western spotted orbweaver Neoscona oaxacensis | 19 | 3% |
| 11 | Gray wall jumper Menemerus bivittatus | 18 | 8% |
| 12 | Noonops coachella | 17 | 100% |
| 13 | Dysdera crocata | 16 | 2% |
| 14 | Cribellate spider Metaltella simoni | 15 | 4% |
| 15 | Habronattus pyrrithrix | 15 | 2% |
| 16 | Habronattus tarsalis | 15 | 7% |
| 17 | Shoreline wolf spider Arctosa littoralis | 15 | 17% |
| 18 | Green lynx spider Peucetia viridans | 14 | 4% |
| 19 | Hogna antelucana | 14 | 70% |
| 20 | Apostenus californicus | 13 | 39% |
| 21 | Hirsute paradise spider Habronattus hirsutus | 13 | 6% |
| 22 | Habronattus signatus | 12 | 7% |
| 23 | Western parson spider Herpyllus propinquus | 12 | 6% |
| 24 | Bull-headed sac spider Trachelas pacificus | 10 | 5% |
| 25 | Colonus hesperus | 10 | 1% |
| 26 | Syspira longipes | 10 | 23% |
| 27 | False black widow Steatoda grossa | 9 | 1% |
| 28 | Bay Area blonde Aphonopelma iodius | 7 | 2% |
| 29 | Giant crab spider Olios giganteus | 7 | 11% |
| 30 | Spotted orbweaver Neoscona crucifera | 7 | 2% |
| 31 | Western lynx spider Oxyopes scalaris | 7 | 1% |
| 32 | Bold jumper Phidippus audax | 5 | 0% |
| 33 | Dictis striatipes | 5 | 50% |
| 34 | Striped lynx spider Oxyopes salticus | 5 | 1% |
| 35 | California flattened jumping spider Platycryptus californicus | 4 | 3% |
| 36 | Desert recluse venomous Loxosceles deserta | 4 | 10% |
| 37 | Green lynx Peucetia longipalpis | 4 | 12% |
| 38 | Homalonychus theologus | 4 | 18% |
| 39 | Pecos brown Aphonopelma steindachneri | 4 | 5% |
| 40 | Phidippus californicus | 4 | 14% |
| 41 | Phidippus nikites | 4 | 12% |
| 42 | Salticus palpalis | 4 | 16% |
| 43 | Sixspotted orbweaver Araniella displicata | 4 | 2% |
| 44 | Steatoda nobilis | 4 | 0% |
| 45 | Banded garden spider Argiope trifasciata | 3 | 1% |
| 46 | Habronattus hallani | 3 | 43% |
| 47 | Hairy tufted jumping spider Phidippus comatus | 3 | 2% |
| 48 | Longbodied cellar spider Pholcus phalangioides | 3 | 0% |
| 49 | California red jumping spider Phidippus adumbratus | 2 | 1% |
| 50 | Desert grass spider Agelenopsis aperta | 2 | 3% |
| 51 | Falconina gracilis | 2 | 5% |
| 52 | Habronattus californicus | 2 | 2% |
| 53 | Hibana incursa | 2 | 2% |
| 54 | McCook's split wolf spider Schizocosa mccooki | 2 | 1% |
| 55 | Red-and-white asagena Asagena fulva | 2 | 20% |
| 56 | Triangulate bud spider Steatoda triangulosa | 2 | 3% |
| 57 | Uloborus diversus | 2 | 1% |
| 58 | Bark lynx spider Hamataliwa grisea | 1 | 3% |
| 59 | Black-and-yellow argiope Argiope aurantia | 1 | 1% |
| 60 | California trapdoor spider Bothriocyrtum californicum | 1 | 1% |
When are spiders out in Riverside County?
Observation records of spiders in Riverside County run through most of the year, peaking in March with 11% of them; across California the peak is April.
What stands out in Riverside County
Species for which Riverside County holds a large share of all California records: Hogna antelucana, 70% (14 of 20); the western diamondback rattlesnake, 56% (95 of 169); the southwestern speckled rattlesnake, 41% (110 of 269); the northern three-lined boa, 41% (56 of 138); Apostenus californicus, 39% (13 of 33); Habronattus ustulatus, 32% (21 of 66); the sidewinder, 28% (537 of 1,923); the western shovel-nosed snake, 27% (400 of 1,482).
Common in California, not on the Riverside County list
Among the snakes most recorded across California, these do not reach the county list: the western terrestrial garter snake (21,830 statewide), the common garter snake (5,777 statewide) and the aquatic garter snake (3,727 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 half-edged wall jumping spider (2,178 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Harmless lookalikes in Riverside 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), 3 of them in Riverside County: treat any snake like this as venomous until identified. Harmless species often taken for them here: the long-nosed snake and the California mountain kingsnake. Widow spiders are on the county list, and so are harmless species often taken for them: the false black widow and the triangulate bud spider. Recluse spiders are on the county list, and so are harmless species often taken for them: the longbodied cellar spider.
Riverside County among California counties
By licensed snake records Riverside County ranks 4th of 58 California counties with any.
Other California counties with their own page: San Diego County, Lassen County, Shasta County, San Bernardino County, Humboldt County, Sonoma County, San Mateo County and Los Angeles 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.