Most Colorado snakes are nonvenomous (nonpoisonous), harmless and beneficial to people because of their appetites for insects and rodents and other pests. In turn, snakes (and their eggs) are eaten by many other species, including skunks and hawks.

Prairie Rattlesnakes

About rattlesnakes

These snakes are venomous (poisonous) and found in grassland areas, most often sunning themselves on rocky outcrops. They prey mainly on rodents but also feed on bird eggs and lizards. These snakes rattle their tails as a warning if you approach too close but may bite as a last resort. Venomous snakes can be observed from a safe distance, as they are generally non-aggressive toward people unless startled, cornered or stepped on.


If you encounter a rattlesnake:

  • Most importantly, remain calm and still at first
  • Give the snake a lot of room and walk around it, or back away
  • Do not handle, move or harass it
  • View a brochure about rattlesnakes in Castle Rock 
Prairie Rattlesnake

Rattlesnake Safety


About bullsnakes

This nonvenomous snake is of the most common, and largest, of snakes seen in Colorado, but often mistakenly confused for rattlesnakes. When threatened, this snake can hiss and mimic rattlesnakes by vibrating its pointed tail to sound like a rattling tail. Bullsnakes can be identified by the oval-shaped head, round pupils and yellowish or cream coloring with dark blotches. Bullsnakes are very beneficial because of their appetite for rodents, as well as birds and bird eggs, which they kill by suffocation or constriction. They are found in a variety of habitats, including riparian areas and woodlands areas. 

Additional information

For more information, call the Colorado Parks and Wildlife Northeast Region Service Center, 303-291-7227. For local assistance with rattlesnakes, call the Castle Rock Police Department Animal Protective Services Division, 303-663-6100.