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Snakes and spiders in San Joaquin County, California

San Joaquin County, home of Stockton, has 12 snake and 14 spider species on record, from 682 licensed snake and 262 spider records. Venomous species here: the western rattlesnake and the western black widow.

12snake species
14spider species
2venomous
Bitten in San Joaquin County? Call 911 for a venomous snakebite or any bite with trouble breathing. For advice on any bite or sting, call Poison Help at 1-800-222-1222 (free, 24/7, U.S.-wide). Do not cut the wound, suck out venom or use a tourniquet. General information, not medical advice. Do not handle or try to identify a snake or spider by this page; if unsure, treat it as venomous.

Are there venomous snakes or spiders in San Joaquin County?

Yes. The western rattlesnake: 177 licensed records, 3% of all California records of it. The western black widow: 39 licensed records, 3% of all California records of it.

What snakes are in San Joaquin County?

In all, 12 snake species are on the San Joaquin County list. The most recorded are the gopher snake (248), the western rattlesnake (177) and the western terrestrial garter snake (55).

#SpeciesRecordsShare of California records
1Gopher snake
Pituophis catenifer
2483%
2Western rattlesnake venomous
Crotalus oreganus
1773%
3Western terrestrial garter snake
Thamnophis elegans
550%
4California kingsnake
Lampropeltis californiae
542%
5Glossy snake
Arizona elegans
483%
6Long-nosed snake
Rhinocheilus lecontei
273%
7Coachwhip
Masticophis flagellum
151%
8Common garter snake
Thamnophis sirtalis
120%
9Eastern racer
Coluber constrictor
91%
10Western black-headed snake
Tantilla planiceps
95%
11Giant garter snake
Thamnophis gigas
87%
12Coast nightsnake
Hypsiglena ochrorhynchus
31%
Source: GBIF records located in San Joaquin County (GADM level 2), read 2026-09-29. Listed from records under any license; counts are CC0/CC BY only.

When are snakes out in San Joaquin County?

Observation records of snakes in San Joaquin County run mostly March through September, peaking in May with 22% of them, the same peak as California as a whole.

January: 0 observation records (0%)JanFebruary: 1 observation record (1%)FebMarch: 8 observation records (8%)Mar8%April: 18 observation records (18%)Apr18%May: 22 observation records (22%)May22%June: 22 observation records (22%)Jun22%July: 5 observation records (5%)JulAugust: 11 observation records (11%)Aug11%September: 6 observation records (6%)Sep6%October: 5 observation records (5%)OctNovember: 2 observation records (2%)NovDecember: 0 observation records (0%)Dec

What spiders are in San Joaquin County?

In all, 14 spider species are on the San Joaquin County list. The most recorded are the western black widow (39), the bold jumper (32) and the Koch's wolf spider (26).

#SpeciesRecordsShare of California records
1Western black widow venomous
Latrodectus hesperus
393%
2Bold jumper
Phidippus audax
321%
3Koch's wolf spider
Alopecosa kochi
263%
4Half-edged wall jumping spider
Menemerus semilimbatus
201%
5Western spotted orbweaver
Neoscona oaxacensis
193%
6Marbled cellar spider
Holocnemus pluchei
111%
7
Dysdera crocata
102%
8
Colonus hesperus
81%
9False black widow
Steatoda grossa
81%
10
Habronattus pyrrithrix
61%
11Triangulate bud spider
Steatoda triangulosa
57%
12Black-and-yellow argiope
Argiope aurantia
32%
13Western lynx spider
Oxyopes scalaris
30%
14
Steatoda nobilis
10%
Source: GBIF records located in San Joaquin County (GADM level 2), read 2026-09-29. Listed from records under any license; counts are CC0/CC BY only.

When are spiders out in San Joaquin County?

Observation records of spiders in San Joaquin County run through most of the year, peaking in September with 19% of them; across California the peak is April.

January: 7 observation records (3%)JanFebruary: 13 observation records (5%)FebMarch: 22 observation records (9%)Mar9%April: 37 observation records (14%)Apr14%May: 15 observation records (6%)MayJune: 26 observation records (10%)Jun10%July: 16 observation records (6%)Jul6%August: 9 observation records (3%)AugSeptember: 50 observation records (19%)Sep19%October: 35 observation records (14%)Oct14%November: 20 observation records (8%)Nov8%December: 8 observation records (3%)Dec

Common in California, not on the San Joaquin County list

Among the snakes most recorded across California, these do not reach the county list: the aquatic garter snake (3,727 statewide), the western aquatic garter snake (3,716 statewide), the sidewinder (1,923 statewide), the ring-necked snake (1,797 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 Johnson jumper (901 statewide), the buttonhook leafbeetle jumping spider (825 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 San Joaquin 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 and the triangulate bud spider.

San Joaquin County among California counties

By licensed snake records San Joaquin County ranks 25th 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.

About these numbers

A species is listed for a state once GBIF holds at least 10 records of it located inside the state by coordinates, under any license. Every count, share, month and county shown is computed only from records published under CC0 or CC BY, so a listed species can show few or no counted records. Monthly patterns show when people record snakes and spiders, which also reflects when people are outdoors. Venomous status follows taxonomy: pit vipers and coral snakes; widow and recluse spiders; the Arizona bark scorpion. Records filed under older names count for the species they belong to today. Full methodology.