Snakes, like all reptiles, are ectothermic, relying on external sources to regulate their body temperature. This presents a challenge during winter months when temperatures drop significantly and food sources become scarce. To survive these harsh conditions, snakes enter a specialized state to endure the cold and conserve energy.
The Winter State: Brumation
During winter, snakes enter a state known as brumation, similar to hibernation in mammals. Unlike hibernating animals that enter a deep sleep, snakes in brumation remain somewhat alert and may occasionally become active. Their metabolism, heart rate, and respiration significantly slow down, allowing them to conserve energy for extended periods without food. Snakes prepare for brumation by reducing their food intake to clear their digestive systems, as undigested food can rot and be harmful.
Environmental cues trigger brumation, primarily dropping temperatures and shorter daylight hours, typically from September to December. While they do not eat during this period, snakes may wake up to drink water to prevent dehydration. The length of brumation varies depending on the climate, with some snakes in warmer regions not needing to brumate at all. Brumation is part of their annual cycle, particularly for species in temperate climates.
Seeking Shelter: Where Snakes Den
For brumation, snakes seek out protected underground locations called hibernacula, which provide stable temperatures above freezing and protection from predators. These sites can be natural formations such as rock crevices, caves, and abandoned burrows made by other animals like rodents or crayfish. They also utilize deep soil fissures, tree root systems, and even large rotting logs. The depth of these dens is crucial, often extending below the frost line to ensure consistent temperatures.
Snakes are opportunistic when selecting hibernacula and may also use artificial structures. This includes old foundations, abandoned wells, basements, crawl spaces, woodpiles, or even open pipes. Some species, such as garter snakes, are known to share hibernacula, forming communal dens that can house dozens to thousands of individuals, sometimes even different species. Other species may brumate alone or in smaller groups.
Emergence and Return to Activity
As spring approaches, rising ambient temperatures and longer daylight hours signal the end of brumation for snakes. Snakes typically begin to emerge when temperatures consistently reach around 60 degrees Fahrenheit, though this can vary by species and location. Upon emergence, snakes are often sluggish and will seek out sunny spots to bask, raising their body temperature to become more active.
Following brumation, snakes prioritize seeking food after their long dormancy. This period also marks the beginning of their breeding season in many species. Males often emerge first, ready to mate as females leave the den, and mating aggregations can occur near the hibernacula.
Encountering Snakes in Winter
It is uncommon to encounter an active snake during the winter months, as they are typically in their brumation sites. However, if a snake is found active on a warmer winter day, it may be briefly emerging to drink water or disoriented. If a snake is encountered indoors, such as in a basement or crawl space, it is likely seeking warmth and shelter.
Do not disturb a snake found in winter, especially if it appears sluggish. Snakes are generally not aggressive unless provoked, and their defensive capabilities are reduced when cold. For safe removal of an indoor snake, contacting local wildlife control services or a professional is recommended rather than attempting to handle it personally.