Snakes and spiders in Pennington County, South Dakota
Pennington County, home of Rapid City, has 8 snake and 7 spider species on record, from 414 licensed snake and 70 spider records. Venomous species here: the prairie rattlesnake and the western black widow.
Are there venomous snakes or spiders in Pennington County?
Yes. The prairie rattlesnake: 63 licensed records, 6% of all South Dakota records of it. The western black widow: 2 licensed records, 67% of all South Dakota records of it.
What snakes are in Pennington County?
In all, 8 snake species are on the Pennington County list. The most recorded are the western terrestrial garter snake (251), the prairie rattlesnake (63) and the plains garter snake (27).
| # | Species | Records | Share of South Dakota records |
|---|---|---|---|
| 1 | Western terrestrial garter snake Thamnophis elegans | 251 | 43% |
| 2 | Prairie rattlesnake venomous Crotalus viridis | 63 | 6% |
| 3 | Plains garter snake Thamnophis radix | 27 | 5% |
| 4 | Gopher snake Pituophis catenifer | 24 | 13% |
| 5 | Smooth green snake Opheodrys vernalis | 22 | 18% |
| 6 | Eastern racer Coluber constrictor | 12 | 9% |
| 7 | Red-bellied snake Storeria occipitomaculata | 8 | 8% |
| 8 | Common garter snake Thamnophis sirtalis | 3 | 1% |
When are snakes out in Pennington County?
Observation records of snakes in Pennington County run mostly April through October, peaking in May with 27% of them; across South Dakota the peak is June.
What spiders are in Pennington County?
In all, 7 spider species are on the Pennington County list. The most recorded are the Apache jumping spider (4), the bold jumper (4) and the banded garden spider (2). Pennington County holds more than half of all South Dakota records of the Apache jumping spider and the western black widow.
| # | Species | Records | Share of South Dakota records |
|---|---|---|---|
| 1 | Apache jumping spider Phidippus apacheanus | 4 | 57% |
| 2 | Bold jumper Phidippus audax | 4 | 22% |
| 3 | Banded garden spider Argiope trifasciata | 2 | 9% |
| 4 | Western black widow venomous Latrodectus hesperus | 2 | 67% |
| 5 | Dark fishing spider Dolomedes tenebrosus | 1 | 33% |
| 6 | Goldenrod crab spider Misumena vatia | 1 | 33% |
| 7 | Tigrosa grandis | 1 | 17% |
When are spiders out in Pennington County?
Observation records of spiders in Pennington County run mostly May through October, peaking in September with 29% of them; across South Dakota the peak is August.
What stands out in Pennington County
Species for which Pennington County holds a large share of all South Dakota records: the western terrestrial garter snake, 43% (251 of 590); the smooth green snake, 18% (22 of 124).
Common in South Dakota, not on the Pennington County list
Among the snakes most recorded across South Dakota, these do not reach the county list: the ring-necked snake (84 statewide), the western foxsnake (64 statewide), the plains hog-nosed snake (40 statewide) and the eastern fox snake (31 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 South Dakota, these do not reach the county list: Pelegrina aeneola (7 statewide), the zebra spider (6 statewide), the brilliant jumping spider (5 statewide), the black-and-yellow argiope (4 statewide), the marbled orbweaver (4 statewide) and the barn funnel weaver (3 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Harmless lookalikes in Pennington County
Rattlesnakes are on the county list, and so are harmless species often taken for them: the gopher snake.
Pennington County among South Dakota counties
By licensed snake records Pennington County ranks 1st of 66 South Dakota counties with any.
The whole state: venomous species in South Dakota, all snakes, all spiders.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.