Knowing when snakes are active in Colorado is important for residents and visitors exploring the state’s diverse outdoor environments. Colorado is home to approximately 30 species of snakes, most of which are not venomous. Understanding their behaviors and preferred conditions helps individuals navigate natural areas with greater awareness and safety.
Colorado Snake Seasons
Snakes in Colorado exhibit distinct seasonal patterns tied to temperature fluctuations. They emerge from winter dormancy (brumation) in early spring, typically March or April, as temperatures warm. This spring period, extending through May, often sees increased activity as they seek food and mates. During peak summer heat, some species become more active during cooler times of the day. As fall approaches, usually September and October, snakes search for dens for brumation, leading to another period of increased visibility before remaining underground until the following spring.
Daily Habits and Environment
Snake activity throughout the day is heavily influenced by environmental factors, especially temperature and sunlight. Being ectothermic, snakes rely on external heat sources to regulate their body temperature. In mild weather, snakes are often most active during the morning and late afternoon or dusk, basking in the sun or hunting. When temperatures are high, snakes seek cooler, shaded areas to prevent overheating, which can lead to them becoming more nocturnal. Conversely, during cooler periods, they may be found stretched out on sun-warmed rocks or pavement to absorb heat.
Snake Habitats in Colorado
Snakes in Colorado can be found across a variety of environments, reflecting the state’s diverse geography. Rocky areas, with their crevices and sun-exposed surfaces, are common locations for many species, including rattlesnakes, which often use rock formations for denning. Grasslands and open prairies also serve as primary habitats, providing cover and abundant prey. Riparian zones, found near rivers, streams, and other water sources, attract snakes that prey on amphibians and fish, such as garter snakes. Snakes may also inhabit suburban areas, sometimes seeking shelter under buildings or in gardens, especially as they look for winter dens.
Identifying Colorado Snakes
Colorado is home to many snake species, with only three being venomous rattlesnakes: the Prairie Rattlesnake, Western Rattlesnake (or midget-faded rattlesnake), and Massasauga. Prairie rattlesnakes are widespread, identified by their triangular heads, rattles at the tail’s end, and often dark blotches on a greenish-gray to brown body. Non-venomous bullsnakes are common and can grow up to six feet long, often yellowish with dark blotches; they may mimic rattlesnakes by hissing or vibrating their tails. Garter snakes, also non-venomous, are generally smaller and often have distinct stripes down their bodies, commonly found near water sources.
Safe Encounters with Snakes
Encountering a snake in Colorado typically calls for observing it from a respectful distance. Most snakes prefer to avoid human interaction and will retreat if given space. If a snake is encountered on a trail, wait for it to move away rather than attempting to provoke or handle it. Wearing appropriate footwear and long pants offers protection in snake habitats, and avoiding placing hands or feet into blind spots helps prevent surprising a snake. In the unlikely event of a snake bite, especially from a suspected venomous species, seek immediate medical attention.