Venomous animals in Colorado
The ones that need the most respect: western rattlesnake, prairie rattlesnake. A bite from any of them is a medical emergency.
- 2 dangerous
- 2 medically significant
- 4 painful, rarely serious
Where they turn up in Colorado
- None recorded
- 1 species
- 2
- 3 to 4
- 5 or more
Venomous snakes in Colorado
Western rattlesnakeDangerous85 records, 10 counties
Prairie rattlesnakeDangerous1,948 records, 43 counties
Western massasaugaMedically significant40 records, 5 counties
Venomous snakes in Colorado: map, photos and look-alikes
Venomous spiders in Colorado
Black widowMedically significant198 records, 22 counties
TarantulaPainful, rarely serious109 records, 10 counties
Venomous spiders in Colorado: map, photos and look-alikes
Scorpions in Colorado
Striped bark scorpionPainful, rarely serious54 records, 8 counties
Northern scorpionPainful, rarely serious28 records, 5 counties
Scorpions in Colorado: map, photos and look-alikes
Centipedes in Colorado
Centipedes in Colorado: map, photos and look-alikes
When they are out
- Venomous snakes
- Venomous spiders
- Scorpions
- Centipedes
Recorded, but not living here
- Rare records Cottonmouth 1 open record
- Rare records Brown widow 1 open record
- Rare records Giant desert centipede 4 open records, latest 2026
A rare record means someone found or reported the animal once or a few times, but there is no known population. Many are strays, pets or hitchhikers in cargo.
Harmless look-alikes in Colorado
- Rattlesnake vs Gopher Snake Gopher snake is harmless
Quick answers for Colorado
- Lives here Rattlesnakes
- Not here Copperheads
- Rare records Cottonmouths
- Not here Coral snakes
- Not here Brown recluses
- Lives here Black widows
- Lives here Tarantulas
Questions
How many venomous snakes live in Colorado?
3 species: Western rattlesnake, Prairie rattlesnake and Western massasauga.
Are there brown recluse spiders in Colorado?
No. There are no open records of the brown recluse from Colorado, and the state is outside its range.
Are there scorpions in Colorado?
Yes: Striped bark scorpion and Northern scorpion.
When are venomous animals most active in Colorado?
Most open records from Colorado fall in May, October to November. Records follow when people are outdoors too, so treat this as a guide, not a rule.
What should I do after a bite or sting?
Call 911 for any venomous snakebite or a severe reaction. For spider bites and scorpion stings, call Poison Control at 1-800-222-1222, free and open 24/7.