What happens to cold-blooded animals like snakes when it gets cold outside?
Do snakes have ways of staying warm in the snow?
Cold temperatures are dangerous for snakes.
Because they’re cold-blooded animals, they need mild climates to survive.
However, plenty of snakes live in areas with pretty harsh seasons.
Curious folks may wonder:
Where do snakes go in the winter?
During winter, snakes will find refuge in holes, caves, burrows, or other shelters located below the frost line. They will remain there until the weather warms.
Read on for more details on how snakes deal with the coldest parts of the year.
How Do Snakes Survive the Winter?
Cold temperatures make a snake’s daily life much more challenging.
Snakes are ectotherms or cold-blooded animals.
This means they rely on the surrounding environment to regulate their body temperature.
They cannot stay warm or cool down through metabolic activity, like humans can when they warm up by exercising, for example.
Instead of battling their way through the worst climate conditions of the year, snakes enter a period of brumation so they can wait out the winter months.
What Is Brumation?
When mammals hibernate, they become wholly dormant and sleep right through the entire winter.
Brumation is essentially the reptilian version of hibernation.
A snake entering brumation will reduce its metabolism to virtually zero.
Its digestion processes come to a halt.
It becomes inactive and extremely lethargic, sometimes sleeping or not moving for days on end.
Brumation is not quite as drastic as hibernation; snakes will sometimes still be awake, just sluggish, while they brumate.
They may move around their burrow to find warmer spots and adjust themselves, too.
On a particularly warm day, especially after a long stretch of cold weather, a snake may emerge from its burrow to bask in the sun and get a drink of water.
It will then return to its den and continue to brumate until spring arrives.
Why Do Snakes Brumate?
Cold temperatures make snakes more susceptible to diseases like respiratory infections.
They also cause snakes to become torpid – lethargic, and inactive.
This means snakes can’t hunt or digest their prey, and they can’t avoid predators if they find themselves under attack.
When snakes get cold enough, they are at risk of death.
Rather than risk starvation, extreme cold, or being found by predators while torpidity has set in, snakes retreat underground and hideout for the winter.
When Do Snakes Brumate?
Brumation can last any time between September and April.
It depends on where the snake lives and the particular weather conditions of the current period.
Snakes in colder climates, like Canada and the northern United States, could brumate for the majority of the year.
Some snakes brumate for eight months!
Snakes at higher elevations also typically need to brumate for more extended periods than snakes in the same regions at lower elevations.
Snakes in warmer climates may only brumate for a couple of weeks or a month.
And snakes located in consistently temperate climates may find there is no need to brumate at all.
Brumation, after all, is a response to cold weather.
If there isn’t any cold weather, then brumation isn’t necessary.
Where Do Snakes Go in the Winter When They Brumate?
To avoid the worst of the cold temperatures, snakes will find a hideout either below the frost line or in a “microclimate” regularly exposed to warmth.
They need to find a place to hide from predators, is warmer than the exposed winter air, and is close to a water source.
Snakes will brumate in other animals’ burrows, caves, holes, underneath logs and rocks, stumps, on south-facing hillsides, or in man-made shelters like basements, barns, and even car engines.
Fossorial snakes – snakes with the ability to burrow – will often dig their holes for brumation.
But most snakes use already-existing shelters.
When snakes find existing burrows, they will either check to make sure it’s unoccupied, or they will eat the inhabitants before taking it over for themselves.
Rodent burrows make especially good hideouts for snakes because they’re structured and deep.
This allows snakes to adjust their positioning to warmer locations throughout the winter and slither deep enough underground to avoid the icy chill of winter air.
Dig Their Own Hole
Fossorial snakes, like the hognose snake and the northern pine snake, sometimes dig their snake holes for brumation.
While these snakes do have the ability to dig, their holes won’t be as structured or lavish as rodent burrows.
When these snake holes don’t suffice as protection from the elements, burrowing snakes will instead resort to taking over an already-existing burrow or sharing one with other snake species like gopher snakes and rattlesnakes.
Snakes will often share their brumation sites with other snakes, even across different species.
Sometimes, a giant pile of snakes in one brumation site is a sign of a lack of options for warm spots in the area.
Other times, it’s common practice for snakes to share their dens.
Rattlesnakes and garter snakes, for example, are known for opening up their winter homes to other snake species.
These group brumation sites are called hibernacula.
How Do Snakes Prepare for Winter?
Snakes will get ready to ingress – enter brumation – by preparing their bodies for an extended period of inactivity and getting to a familiar place.
They’ll eat more before brumation to “fatten up” if they’re able to find more prey than usual.
Snakes must fully digest all of their food before ingress, so they’ll stop eating altogether around 10 days beforehand.
Many species of snakes will return to the same brumation burrows year after year.
Before ingress, they’ll hang out nearby and get ready for the cold to set in.
What Are Dangers of Brumation?
Snakes reduce their risk of death when they during the winter.
However, winter is still a dangerous time of year for these reptiles.
Snakes must completely digest all food in their body before they brumate.
If food remains anywhere in their gut – undigested in the stomach, halfway through their intestines, etc. – then it will rot, and the snake will die.
Because a snake’s metabolism is virtually zero during brumation, they are unable to digest food.
This is a noteworthy fact for snake owners who want to mimic brumation for their pet snakes.
If snakes encounter warm-enough temperatures during brumation, their metabolism will kick in, and they will begin burning fat again.
If the snakes are unable to find food after this happens, their body will continue burning their fat reserves until they starve.
Desiccation (Dying of Thirst)
Losing water reserves is a more common cause of death during brumation than starvation is.
Water can stay in the body much longer than it would when the snake is regularly active.
However, snakes must still occasionally drink water throughout their brumation season.
This is why they must find a burrow close to a water source.
Attacks from Predators
Especially during an especially harsh winter, predators like skunks will also burrow to find warmer shelter.
If they happen upon a dormant, lethargic snake, it’s bad news for the snake.
When snakes occasionally emerge from their dens on a warm day during the winter, they risk encountering predators as they bask in the sun and drink water.
They’re still very lethargic when they’re doing this and are susceptible to predatory attacks.
How Do Snakes Come Out of Brumation?
When snakes egress – exit brumation – they will spend several weeks in and around their burrows while the temperature continues to warm up.
Snakes will bask in the sun during the day, then retreat to their dens at night.
They may also retreat to other nearby hiding places different than their burrow.
Snakes will egress when the temperature becomes warm enough for them to begin to function normally.
This is a slightly different temperature depending on the species.
As an example, rattlesnakes will emerge from their burrows once the daytime temperature reaches a consistent 60° degrees Fahrenheit (16° C).
After a successful brumation, a snake will emerge weighing approximately the same as before it began to brumate.
Once snakes have acclimated to their normal activity levels, it is time to shed and breed.
Females will shed after brumation, exposing pheromones to attract the males.
Mating is often the first thing snakes will do after brumation, even before they eat a meal.
It’s saying something, considering they sometimes haven’t eaten in eight months!
Knowing where snakes go in winter is surprising.
Snakes are opportunists, finding any kind of crack or crevice capable of providing them with warmth and privacy.
Brumation is a natural response to cold temperatures and is also a mating-season marker for many snakes.
The cold-blooded creatures they are, snakes must take special precautions during the winter months.
They protect themselves by finding secure shelter where they can wait out the coldest and most dangerous months of the year.
Here in these cozy homes, they’ll chill out until warmer weather arrives.