What Do Snakes Do During the Winter in Colorado?
It's pretty common to come across snakes while out and about on Colorado trails during the spring and summertime, but where do these reptiles go when winter rolls around?
Since snakes aren't capable of producing their own body heat, they have to find another way to stay warm when the weather gets cold. To do this, and also avoid freezing, they make their way underground. However, their process is known as brumation rather than hibernation.
Snakes usually start searching for a den in September and begin brumation in October and November. They remain underground until about late March to early May. Their process has a fairly predictable pattern each year but can vary slightly depending on the elevation. Unlike other animals that eat a bunch of food to fatten up before winter hibernation, snakes' bodies instead go into a state of sluggishness and extended resting, because they can't digest very well when their body temperature is low.
The places where snakes seek protection in the winter are called "hibernaculum." These dens are below the frost line and are easy for them to find. In fact, sometimes the same snakes will return to the same hibernacula year after year.
The cold-blooded creatures take advantage of rodent burrows by using them to travel underground. Juveniles will frequently follow the scent trail of adult snakes to find the best routes to the hibernaculum. The Front Range also offers a geologic landscape that creates perfect natural cavities and passages between rocks where snakes can seek shelter.
According to CPW, multiple snakes will occupy the same hibernaculum without any conflict - even different kinds of species, such as garter and rattlesnakes, have no problem sharing a space for the winter. Plus, when they are all clumped together in a large ball, it helps to conserve heat. Rattlesnakes, in particular, are often found in high concentrations near their winter dens right before the onset of brumation.
Also unlike other animals, snakes do not go into a deep sleep during the winter. On mild days, snakes will sometimes even come out of their den to soak up the sun and find food and water.
Snakes' diets consist of ground squirrels, prairie dogs, mice, rabbits, lizards, and ground-nesting birds, toads, lizards, small snakes, mice, and centipedes.
As the soil and rocks start to warm up in the spring, the snakes come out of their winter resting spot. Once active, adult snakes may migrate several feet from their dens in search of food.
Hibernacula are very difficult to identify without snakes present. If one is found, it's important not to disturb it.