Surviving the Cold: How Do Snakes Hibernate?

You already know that snakes have slower metabolisms than most other animals. This is the perk of being a cold-blooded animal that relies on its environment to regulate body temperature.

Not all snakes hibernate, but some do, especially those living at higher altitudes with colder climates.

Today, we will discuss snake hibernation and assess the factors triggering the behavior, as well as the physiological changes that the snake’s body undergoes during the process. So, let’s discuss it!

Hibernation Physiology in Snakes

Snakes undergo several physiological changes during hibernation, including:

Metabolic Changes

The hibernation process dramatically decreases the snake’s metabolism, depending on the species, environmental conditions, and the hibernation process itself. Some snakes enter a mild torpor state, where they still drink water and remain moderately active.

Other species undergo more intense hibernation, during which they exhibit profuse lethargy with minimum-to-no activity levels. The animals’ metabolisms vary depending on the case.

Once the snake’s metabolism drops, the snake will reduce its heart rate and decrease its need for oxygen and nutrients.

This allows the reptile to undergo periods of low temperatures and lack of prey; the option is to simply die due to starvation and hypothermic shock.

Vernalization Process

The vernalization process refers to specific hormonal changes that occur in snakes during the cold season.

Here are some bullet points for a clearer picture:

  • The lower temperatures inform the snake that the cold season is underway
  • The snake’s system reacts immediately, lowering the animal’s metabolism accordingly
  • An automatic hormonal response is triggered, causing the snake’s body to produce reproduction-specific hormones
  • The hormones enter a latent state during the hibernation journey, which may last for several months
  • As the warm season sets in and temperatures begin to rise again, the snake’s reproductive hormones become active
  • This triggers the snake’s mating and breeding behavior, which explains why some species only reproduce via vernalization

An important note here, the physiological changes triggered by the vernalization process aren’t identical to those linked to hibernation.

So, a snake undergoing vernalization isn’t actually hibernating because temperatures aren’t low enough. Instead, the snake’s metabolism will drop a bit, but never to the point of triggering a hibernation-like state.

The snake will return to normal once the temperatures begin to rise again.

Another important note here, these snake species should undergo vernalization even in captivity. Otherwise, they won’t be able to reproduce.

Body Temperature Changes

The change in body temperatures among hibernating snakes is called torpor. The interesting aspect here is that the snake’s body temperature will match that of the surrounding environment.

For instance, some snakes prepare for hibernation in underground burrows where they’re safe from predators. The overall temperature in the burrow is higher than that on the surface. So, the snake’s body temperature will match that inside the burrow.

However, some snakes enter torpor at the surface, either hidden in foliage or hiding in trees. In their case, the body temperature is lower, matching that of the surrounding environment.

When in torpor, the snake’s body temperature cannot drop below that of the environment because the latter influences the snake’s temperature directly.

The snake’s metabolism will drop accordingly during this time, removing the snake’s need for nutrients for months to come.

Breathing and Eating Habits

The snake’s breathing slows down dramatically during torpor. This causes the animal to take shallower and rarer breaths, forcing the body to produce less CO2 and enter an energy-conservation state.

The effect is similar with regard to feeding. Snakes typically stop eating several weeks before torpor, which allows their body time to switch to its fat reserves.

Snakes store fat in their tails primarily, and they rely on these reserves during the hibernation process. The body enters an automatic energy-saving state, during which it will use the stored fat as nutrients. The snake’s fat reserves will deplete at a slow rate, keeping the animal sufficiently nourished to complete the hibernation journey.

Adaptations for Survival During Hibernation

Snakes don’t enter hibernation on their own accord. It’s not a choice but rather a behavior dictated by the environment itself.

So, snakes had to adapt to the seasonal cycle to survive the rough cold season.

They have achieved this via several mechanisms, such as:

  • Torpor – As mentioned, torpor refers to the snake’s ability to lower its metabolic rates and decrease its breathing and digestive system. This allows the animal to conserve energy and consume fewer nutrients during the cold season.
  • Thermoregulation – Snakes exchange temperature with their surrounding environment. This allows them to match their bodies’ temperatures to those of the surrounding habitat. Thermoregulation is critical for preventing temperature shock during the cold season.
  • Fat deposits – Snakes have developed the ability to store fat in their tails and other areas of the body for later use. This provides the snake with the ability to absorb nutrients during a time when hunting and feeding are no longer available.
  • Hibernacula – This is the more pretentious term for a hibernation site. Snakes have adapted to sense when the cold season comes and begin to look for a proper hibernation site in time.
  • Vernalization – Snake species that live in colder regions with separate seasons had to adapt to their geographical area. Undergoing vernalization is one such adaptation, where snakes produce their reproductive hormones as soon as the cold season ends. This allows them to breed during the cold season so that the young can mature enough to survive the next cold season.
  • Controlling the heart rate – Snakes undergoing torpor can control their heart and breathing rate. This is essentially the foundation of the snake’s ability to adjust its metabolic rates based on environmental influences.

Benefits of Hibernation for Snakes

While the benefits of hibernation for snakes can separate into several multiple categories, I prefer to condense them into 3 major sections:

  • Improve survivability – This one is fairly obvious. The cold season impacts the snake’s ability to hunt, both due to the dangerously low temperatures and the scarcity of prey. Entering hibernation allows the snake to cease eating and conserve energy throughout the cold season. During this time, the reptile will survive on its stored fat resources.
  • Ensure population stability – Without the ability to hibernate, the snake population will diminish fast. One could say that snakes won’t even be able to survive during the cold season if they lack the ability to control their metabolism and body function.
  • Ensure proper reproduction – We’ve already discussed vernalization and how it impacts the snake’s breeding behavior. Snakes that have adapted to the cold season and undergo vernalization can only reproduce in a cycled seasonal ecosystem. Forcing these snakes to live in a tropical area will render them unable to reproduce anymore.

These benefits show that some snake species have adapted to the cold season so well that they cannot survive in any other ecosystem.

Types of Snake Hibernation

There are 2 primary types of hibernation among snakes depending on their geographical area:

  1. True hibernation – True hibernation only occurs in cold regions with cyclic seasons. Snakes inhabiting these areas enter a state of torpor, during which they reduce their metabolism, heart rate, breathing frequency, and digestive activity. The snakes won’t move much during this time, will conserve energy, and will rely on their stored fat reserves to survive the cold season.
  2. Aestivation – Aestivation is the direct opposite of hibernation. This behavior is similar in nature, but it is triggered by different parameters. Aestivation has the same underlying mechanism, in the sense that the snake lowers its metabolism, breathing, and heart rate to conserve energy for a given time window. The difference is that aestivation occurs during hot summer days rather than cold ones. This behavior is specific to snakes living in hot and arid environments where summertime temperatures can jump over 120 F.

While hibernation and aestivation have completely opposed triggers, they realistically function the same.

The underlying goal is to lower the animal’s metabolism and nutrient consumption activity, allowing the snake to survive the harsh environmental conditions until it’s safe to come out again.

Common Types of Snake Hibernation Practices

Snakes exhibit 2 opposite hibernation behaviors:

  • Denning in groups – Western rattlesnakes tend to den in groups when the right time comes. Rattlesnakes aren’t social animals, but they will group up in some situations, such as hibernation. The group hibernation provides rattlesnakes with improved thermoregulation, as they exchange heat with one another, and increased protection against predators.
  • Solitary denning – Garter snakes, and many other species, den alone, typically in carefully-selected burrows, to protect themselves from predators.

It’s worth noting that there’s no such thing as a group denning-specific species. Even Western rattlesnakes only den in groups as a last resource.

They prefer to hibernate alone whenever necessary, except that’s not always possible. If the cold season approaches fast and they cannot find an adequate hibernation spot safe from predators, they will share space for improved protection and safety.

Factors Impacting Snake Hibernation in the Wild

Whether a snake can hibernate or not and how prepared they are for the journey varies based on multiple factors.

These include:

  • Availability of food sources and prey – Snakes require to have sufficient fat reserves before being able to hibernate. If not, they might not be able to do it. While the snake’s metabolism drops significantly during torpor, it won’t stop entirely. So, the snake will still consume resources, just not from hunting. Instead, it will rely on its fat reserves to keep its body well-nourished for the months to come. If the snake doesn’t have sufficient fat stored, it won’t enter torpor and could die as a result.
  • Temperature variations in the environment – Snakes only begin their hibernation once environmental temperatures reach a specific value. This means that there are variations in the time window depending on when temperatures reach those ideal values. It also means that global warming will most likely impact the snakes’ ability to hibernate properly. If the climactic changes are too abrupt, hibernating snakes may no longer be able to enter torpor, which can have catastrophic effects for reptiles practicing vernalization.
  • Geographic location and seasonal changes – The snakes’ ability to hibernate varies wildly depending on geographical location and respective seasonal changes. This means that different snake species undergo hibernation and different times and for varying durations, depending on the specifics of their ecosystem.

Common Locations Where Snakes Hibernate

Snakes begin their hibernation in a variety of spots and areas, depending on the species’ behavior.

Arboreal snakes tend to hibernate in trees or at ground level, hidden in the foliage. Other snakes look for burrows to…borrow, rock crevices, natural tunnels, or other hidden locations.

This is to ensure a higher level of security and comfort. Snakes are extremely vulnerable when undergoing hibernation because they are no longer able to protect themselves from predators.

So, it’s in their best interest to find a secure location during this time.

Preparing Pet Snakes for Hibernation

If you own a hibernating snake pet, you need to consider 3 critical points:

  1. Health assessment – You should first make sure that your snake can undergo hibernation, to begin with. Consult a reptile vet to make sense of your snake’s health status beforehand. If your snake doesn’t have the right weight or sufficient fat deposits or is dealing with various health problems, hibernation might not be an option. Don’t skip this step!
  2. Creating a suitable environment – Your snake requires a specific habitat layout to hibernate properly. Provide the reptile with a personalized hiding spot to instill security and comfort, or your pet might have difficulties hibernating properly.
  3. Hibernation-safe diet plan – When it comes to preparing your snake for hibernation from a nutritional perspective, you have 3 points to check. The first one is the food quality. Snakes require high-calorie meals several weeks before hibernation begins. Go for rats or other larger animals, depending on your snake’s feeding capabilities, and even increase the feeding frequency a bit. For a second point, stop all feeding 2-3 weeks before hibernation. Remember, the snake’s metabolism will drop significantly, and any food still present in its digestive system will no longer be digested. You don’t want the snake’s food to rot in its belly. The third point refers to providing the snake with sufficient water up to the point of entering hibernation and during the entire process.

Care During Pet Snake’s Hibernation Period

Fortunately, snakes don’t have any meaningful maintenance requirements during the hibernation phase.

The animals will decrease their metabolism dramatically during hibernation, which leaves them in a dormant state.

However, there are some areas that may require your input. These include:

  • Environmental parameters management – You should regulate and monitor your snake’s temperature, humidity, and ventilation during the hibernation journey. Aim for temperatures around 35-50 F, depending on your snake’s natural preferences, humidity levels between 40 and 70%, and sufficient ventilation to ensure optimal aeration and humidity control. Keep in mind that most snakes exit their hibernation state the moment temperatures reach 60 F.
  • Cleanliness maintenance – You don’t really need to clean your snake’s enclosure during the hibernation phase, as the snake doesn’t eat nor drink during this time. However, you should perform some pre-hibernation cleaning and disinfecting to make sure there’s no bacterial growth during the process. Also, monitor your snake during hibernation so you can detect any degradation in terrarium cleanliness over time. You may need to clean the walls occasionally and even replace the substrate after a while to prevent bacterial formation.


Not all snakes hibernate, but those that do require special care in captivity.

You should always consider your snake’s hibernation behavior when setting up the habitat.

Robert from ReptileJam

Hey, I'm Robert, and I have a true passion for reptiles that began when I was just 10 years old. My parents bought me my first pet snake as a birthday present, which sparked my interest in learning more about them. read more...