DENVER (KDVR) — Most snakes in Colorado are harmless to humans, but there are three kinds that can be dangerous.

Not only are most harmless, but even beneficial to humans thanks to their appetite for rodents and insects.

Rattlesnakes usually avoid humans, but a new study found that they are more social than previously thought.

About 8,000 people are bitten by venomous snakes in the United States each year, with 10 to 15 deaths, according to the U.S. Food and Drug Administration.

According to Colorado Parks and Wildlife, if you see these kinds of rattlesnakes, you should “simply back off.”

Prairie rattlesnake

While it typically enjoys open grasslands, it can be found in forested areas. According to CPW, it often seeks spots where it can hide and can be found in thick grass or shaded badlands.

Prairie rattlesnakes can grow up to 5 feet long and are identifiable with features like a triangular head with heat-sensing pits on the sides, elliptical pupils and a body covered in dark blotches with, of course, a rattle on its tail.

The snake uses thermal sensitivity to hunt its prey, which means the snake “senses your presence by your body heat,” according to CPW.

Desert massasauga rattlesnake

Like its name, this snake typically hangs out in desert areas, barren of water and grass. Its body is covered in dark spots contrasting pale space in between.

According to a report from CPW, its largest-known populations are in several areas of Colorado, particularly the southeastern portion.

However, it is considered a Species of Special Concern in Colorado, meaning that its population is locally threatened.

Midget faded rattlesnake

This snake is small but mighty. It’s light tan in color with brown spots. It can grow up to 30 inches in length, but its venom is among the most lethal of its species, according to Colorado Partners in Amphibian and Reptile Conservation.

It is peaceful until it feels disturbed or spooked, that’s when it acts defensively and rattles and potentially strikes.

In Colorado, midget faded rattlesnakes will live in just about every terrestrial habitat in its geographic and elevational range. They can be found within the Green River formation, including semi-desert shrubland, riparian zones and woodlands.

However, like the desert massasauga rattlesnake, it is considered a Species of Special Concern.

Staying safe

According to CPW, there are ways that you can modify your property to keep dangerous snakes away.

  • Do not landscape with expanses of large rocks, especially in open sunny areas.
  • Mow weeds and vegetation, and remove rocks, boards and debris.
  • Reduce the rodent population on your property to reduce a major food source for snakes.
  • Seal entrances to crawl spaces and basements.

If you encounter one, CPW says you should back off, because the snake can sense your presence through heat and movement.

If the rattlesnake poses a threat, you can legally kill it in Colorado.