Venomous snakes and spiders in Montana
Montana has one venomous snake species among the 9 snake species listed there: prairie rattlesnake. The prairie rattlesnake accounts for the most records (344), and venomous species make up 27% of all 1,278 licensed snake records in the state. On the spider side, one species is medically significant: western black widow.
Venomous snakes of Montana
The only venomous snake on the Montana list is the prairie rattlesnake, with 344 licensed records, 27% of all snake records in the state.
Dangerous spiders of Montana
One widow species (Western black widow: 9 records) is on the Montana list. There is no recluse spider on the Montana list: no recluse species reaches 10 records in the state. Widow bites cause muscle pain and cramps; recluse bites can cause a slow-healing wound. Both are rare and seldom fatal.
Are there scorpions in Montana?
Yes. One scorpion species is recorded in Montana, from 5 licensed records: Northern scorpion (5 records). Every scorpion has venom; only the Arizona bark scorpion's sting is medically significant, and it is not on the Montana list.
Other snakes recorded most in Montana
These eight account for 72% of all licensed snake records in Montana; the most recorded, the western terrestrial garter snake, alone for 33%.
Other spiders recorded most in Montana
These eight account for 28% of all licensed spider records in Montana; the most recorded, the McCook's split wolf spider, alone for 11%.
Related species: Pardosa saxatilis
Related species: Pardosa saxatilisWhen venomous snakes are out in Montana
Observation records of venomous snakes in Montana run mostly April through August, peaking in April with 35% of them. December through February together hold under 2% of the records, so venomous snakes in Montana are rarely recorded in winter.
When spiders are most active in Montana
Observation records of spiders in Montana run mostly April through September, peaking in July with 22% of them. December through February together hold under 2% of the records, so spiders in Montana are rarely recorded in winter.
Counties with the most venomous snake records
Chouteau County has the most records of venomous snakes in Montana, 102, most of them of the prairie rattlesnake. Carbon County and Wheatland County follow.
| # | County | Records | Most recorded there |
|---|---|---|---|
| 1 | Chouteau County | 102 | Prairie rattlesnake |
| 2 | Carbon County | 49 | Prairie rattlesnake |
| 3 | Wheatland County | 34 | Prairie rattlesnake |
| 4 | Teton County | 21 | Prairie rattlesnake |
| 5 | Phillips County | 19 | Prairie rattlesnake |
| 6 | Cascade County | 19 | Prairie rattlesnake |
| 7 | Petroleum County | 11 | Prairie rattlesnake |
| 8 | Toole County | 10 | Prairie rattlesnake |
| 9 | Lake County | 8 | Prairie rattlesnake |
| 10 | Sanders County | 8 | Prairie rattlesnake |
Where in Montana are snakes recorded most?
Carbon County leads with 124 records (10%), followed by Chouteau County and Sanders County; the top five counties hold 43% of the total. 49 of Montana's 56 counties have at least one licensed snake record.
| # | County | Records | Share |
|---|---|---|---|
| 1 | Carbon County | 124 | 9.7% |
| 2 | Chouteau County | 124 | 9.7% |
| 3 | Sanders County | 112 | 8.8% |
| 4 | Lake County | 108 | 8.5% |
| 5 | Missoula County | 82 | 6.4% |
| 6 | Ravalli County | 67 | 5.2% |
| 7 | Yellowstone County | 65 | 5.1% |
| 8 | Fergus County | 49 | 3.8% |
| 9 | Phillips County | 47 | 3.7% |
| 10 | Big Horn County | 39 | 3.1% |
| 11 | Wheatland County | 37 | 2.9% |
| 12 | Cascade County | 32 | 2.5% |
Montana county with its own page: Missoula County.
Are there poisonous snakes in Montana?
Yes. Montana has one venomous snake species on its list, the kind people usually call poisonous: prairie rattlesnake. Strictly, snakes are venomous (they inject venom), not poisonous (harmful to eat or touch).
Are there rattlesnakes in Montana?
Yes. One species is on the Montana list: the prairie rattlesnake, with 344 licensed records. Most licensed records of the prairie rattlesnake come from Chouteau County, Carbon County and Wheatland County.
Are there copperheads in Montana?
No. GBIF holds no copperhead record for Montana under any license.
Are there cottonmouths (water moccasins) in Montana?
No. GBIF holds no cottonmouth record for Montana under any license.
Are there coral snakes in Montana?
No. GBIF holds no coral snake record for Montana under any license.
Prairie rattlesnake (Crotalus viridis)
Montana has 344 licensed records of the prairie rattlesnake, which ranks the state 6th of the 14 states where it reaches our threshold. Its observation records in Montana run mostly April through August, peaking in April; most licensed records come from Chouteau County, Carbon County and Wheatland County. Range in other states and photos: Prairie rattlesnake profile.
Harmless lookalikes in Montana
Many snakes and spiders taken for venomous ones are harmless species with a similar look. These are the usual confusions, with each species' licensed records in Montana.
What looks like a copperhead in Montana
No copperheads reach the Montana list, and GBIF holds no copperhead record for Montana under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: central plains milksnake (12).
What looks like a rattlesnake in Montana
Rattlesnakes: 344 licensed records in Montana. Harmless species often taken for them are also on the state list: gopher snake (147) and plains hog-nosed snake (19). Together they have 166 licensed records, and here the venomous species are the more recorded side, 2.1 to 1.
What looks like a coral snake in Montana
No coral snakes reach the Montana list, and GBIF holds no coral snake record for Montana under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: central plains milksnake (12).
What looks like a widow spider in Montana
Widow spiders: 9 licensed records in Montana. Harmless species often taken for them are also on the state list: triangulate bud spider (on record). The lookalikes are on the list from records under other licenses, with no openly licensed records to count, so the two sides are not compared.
What looks like a recluse spider in Montana
No recluse spiders reach the Montana list, and GBIF holds no recluse spider record for Montana under any license, so a spider taken for one here is most likely a harmless lookalike. Those recorded in the state: hobo spider (8).
How Montana compares
By count of venomous snake species, Montana ranks 37th of 50 states, level with 8 other states. Nationally, Arizona leads with 14 species; five list none.
Of the four states bordering Montana, Idaho and Wyoming list more venomous snake species; North Dakota and South Dakota list as many (Montana: 1 species; Idaho 2, Wyoming 2, North Dakota 1, South Dakota 1).
Venomous snakes listed next door but not in Montana: the western rattlesnake (Idaho and Wyoming). The most widely shared is the prairie rattlesnake, listed in all four bordering states.
Are there poisonous spiders in Montana?
Does Montana have black widows?
Yes. One widow species is on the Montana list: the western black widow (9 records).
Does Montana have brown recluse spiders?
No. GBIF holds no brown recluse record for Montana under any license.
Western black widow (Latrodectus hesperus)
Montana has 9 licensed records of the western black widow, which ranks the state 13th of the 18 states where it reaches our threshold. Range in other states and photos: Western black widow profile.
More for Montana
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.