Somewhere between two and four feet (depending on where you live in New England) beneath our feet there is a “frost line” below which the ground water in soil doesn’t freeze. Snakes, being reptiles, are ectotherms, and their bodies assume the temperature of the air around them. In order to avoid being frozen to death in the winter, they retreat below the frost line, where they enter a state called brumation – the cold-blooded term for a state of torpor and inactivity that is not true hibernation, but in which a dramatic slowing down of bodily functions occurs. Crevices in south-facing rocky ledges and abandoned woodchuck, fox and skunk dens (and human cellars) often serve as hibernacula, or winter shelters. Common Gartersnakes are known to gather in large numbers (one Canadian den served as a hibernaculum for 8,000 gartersnakes), in order to concentrate the small amount of heat their bodies produce in the winter.
As the air temperature lowers in the fall, a snake’s body temperature falls and its metabolism decreases dramatically. Gartersnakes actively prepare for this by not eating for several weeks prior to hibernating. This allows all of the food they previously consumed to be completely broken down and absorbed into their system. To enhance this process, gartersnakes bask in the sun both before and during their early days of sheltering in hibernacula, warming themselves so as to increase the rate of their metabolism just prior to hibernating.
Should a snake happen to eat a large grasshopper, earthworm or small frog just prior to entering brumation, the snake may become extremely lethargic due to the slowing down of its metabolism, and the contents of its stomach may not be digested as quickly. The longer it takes to process food in its stomach, the greater the chances that this dead material will start to decay, which could result in serious illness to the snake.
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