Written by Stacey of Reptile Guide

In nature, when the going gets tough, the tough get going... straight into warmly insulated dens, in the case of frigid winter weather.

Jarvis, one of Josh's Frogs' resident Bearded Dragons

Many people know that bears, squirrels, and other mammals native to seasonally frigid environments enter a dormant state to survive, but did you know that some reptiles do, too?

What is Brumation? Reptile Dormancy Meaning Explained

Although it takes place during the same time of year for the same purposes as hibernation, most reptiles' dormancy during winter is called brumation.

When a reptile is brumating, it becomes mostly inactive and very slow-moving. It may stay in the same spot for weeks at a time, eventually moving to find water, only to go dormant again. Its heart rate and breathing rate slow down significantly. Little to no digestion occurs, so they typically don't eat, but they still need to drink water.

Just like mammals, reptiles enter this seasonal state to survive periods of cold temperatures and low resources. Being cold-blooded, reptiles are even more susceptible to extreme temperatures.

Adult Male Red Tegu (Salvator rufescens)

Without brumation, we wouldn't be able to enjoy wild snakes and lizards in seasonal climate zones—they'd only survive in the tropics!

Comparison to Hibernation

As we touched on above, there are quite a few similarities between mammalian hibernation and reptilian brumation.

In both instances:

● The animal becomes inactive.

● It’s a survival mechanism for periods of low temperatures and scarce resources.

● The animal will retreat to a well-insulated den, crevice, burrow, or pile of organic matter called a hibernaculum.

However, there are some key differences.

Hibernating animals typically don't wake up at all. They don't urinate, defecate, eat, or drink. All brumating reptiles still need to drink water, and sometimes they may even eat and eliminate—these activities would simply be drastically reduced compared to normal.

Which Reptiles Brumate

Most cold-blooded animals endemic to areas that experience cold winters naturally brumate to survive the harsh season. This includes lizards, turtles, snakes, and even frogs and salamanders.

Green Keel-Bellied Lizard (Gastropholis prasina)

To complicate matters, some turtles and amphibians may hibernate instead of brumating, depending on which defining characteristics you use for each state of dormancy.

North American colubrids, leopard geckos, and bearded dragons are some of the most common captively-kept reptiles that brumate, but there are many, many more.

Reptiles whose native ranges sit near the equator don't naturally experience temperatures cold enough to brumate. These are known as equatorial species. Boa constrictors, Burmese pythons, ball pythons, and iguanas are among the most prevalent equatorial species in captivity. Still, seasons and minor temperature fluctuations do have an impact on their behavior. For example, colder weather and shorter daylight hours typically signal the onset of the breeding season.

Why Reptiles Brumate

Let’s now discuss the three primary reasons why this behavior occurs.

Lack of Food and Water Availability

During winter, the entire ecosystem slows down. Most plants stop growing, insects are no longer active, and water freezes over, making it harder to access.

These impacts on the lower end of the food chain crawl upwards and impact virtually every organism. Without insects and plant matter, small prey animals have nothing to eat. Without small prey animals, apex predators are left hungry. This lack of food and water availability is one reason that reptiles brumate.

Inability to Control Their Body Temperature

Additionally, and perhaps more significantly, reptiles are unable to control their body temperature. They are ectothermic, or cold-blooded, so they must use their environment to warm themselves. If their environment is cold, they can't warm themselves. If reptiles can't warm themselves, their digestion and other essential biological functions are halted or slowed down. They're unable to fight off infections, heal from injuries, or move quickly to catch prey or escape from predators.

Environmental Changes

Most reptiles do not have any need to brumate in captivity because their source of food, water, heat, and light is artificially controlled—by you! Sometimes, though, a captive reptile's biological instincts take control and signal dormancy over minor changes, like an ambient temperature drop of only a few degrees, or shorter daytime hours as visible through windows.

Yellow Spotted Climbing Toad (Pedostibes hosii)

Realistically, the only captive animals that won’t be aware of these subtle changes are animals that are kept in temperature-controlled rooms in tubs and racks that limit the amount of light they can see. Even if you keep your thermostat set to the same temperature year-round, the ambient temperature in the room and, thus, on the cool side of the enclosure, naturally drops by a few degrees in most households during winter. And even if you keep your artificial lighting set on the same timer year-round, if there are windows in the room, it will still be brighter when the sun is out and darker when the sun is down.

Other times, a keeper may opt to induce brumation for breeding or health purposes.

How the Seasons & Brumation Effect Reproduction

In the wild, annual brumation signals females' bodies to start preparing for ovulation and males' bodies to start producing sperm. When spring hits and those reptiles begin to warm up, often the first thing on their mind is finding a mate. This is even more true in males than it is in females, who might be interested in finding food, too.

Even in tropical species that do not fully brumate, the minor temperature differences are enough to trigger them to breed during the cold season so that their babies will all be born or hatch around the same time when There's an abundance of resources available.

In captivity, it's debatable whether these conditions are necessary to induce reproductive behaviors in reptiles. Many keepers have had a large amount of success without brumating their animals at all. On the other hand, some keepers report higher infertility rates and smaller clutches or litters when they don't cool their animals.

Hatching Green Keel-Bellied Lizard (Gastropholis prasina)

Breeding & Brumation

If breeding is the name of your game, you might want to thoroughly deliberate about the pros and cons for your specific situation. It can be fun to experiment with attempted breeding without brumation, which avoids the associated risks. Some living situations make attaining the parameters for brumation difficult and inconvenient, as well.

Brumation’s Health Impact

Beyond breeding, some keepers enjoy replicating an animal's natural conditions as much as possible. This is not a bad thing. While there are risks that your pet may get sick, or isn't strong enough to make it through, others believe that giving the body an annual "break" from digestion and activity helps them to live a longer, healthier life.

This can be loosely compared to suspended animation seen in some invertebrates, or "putting your pet's life on pause." Perhaps this is the key to the long life that reptiles live, compared to other animals. Fasting has even proven to offer health benefits for humans, so why not herps, too?

Preparing a Reptile for Brumation

If you own a reptile and you intend to brumate it, or you know that your pet goes into brumation on its own every year, Reptile Guide recommends you start preparing a few months ahead of time.

Feedings & Caloric Intake

Ideally, caloric intake will be slightly increased through more frequent feedings and high-fat food items in the preceding months. This is especially true if your reptile experienced a hunger strike or illness during the year, or if you intend to breed your animals. Allowing them to create adequate fat stores will help them to make it through the dormancy healthily and with enough energy to return to normal activities when the temperatures go back up.

You'll want to slow down and eventually cease feeding your snakes, leaving a minimum of two to three weeks since the last meal before the temperature starts dropping. Lizards can still be offered food around once a week, even during brumation, but they will typically refuse it. Water should always be available to brumating herps.

Physical Exams

An annual physical exam, bloodwork, and parasite testing by your veterinarian shortly before brumation is also a great idea. This vulnerable dormant state often allows previously non-problematic organisms, like bacteria, fungi, and parasites, to multiply and cause significant health issues. Damaged organs are also unable to heal or compensate as they usually do when your reptile is warm.

It's not uncommon for weakened animals to die during brumation, and even healthy animals run the risk of contracting a respiratory infection from chilly temperatures. You'll want to make sure your pet's health is in tip-top shape before it’s time to brumate.

Research!

Research the appropriate temperature and, perhaps, lighting parameters for brumation for the animal you own. It varies from species to species. You should usually aim to reach these temperature and lighting guidelines gradually, over weeks, just like the seasons change gradually in nature.

The Start & End of Brumation: How Long Brumation Lasts

The length of brumation varies widely from animal to animal, depending on species, geographical region, yearly temperature variances, age, and sex.

Generally, brumation begins sometime in the fall, when the daylight hours start reducing, and the temperature starts falling. Reptiles then start to become more active in spring, when the days start getting longer, and the temperatures rise back in the optimum range. This process is typically two to three months long.

Jarvis, one of Josh's Frogs' resident Bearded Dragons

Bearded dragon owners have reported that their lizard brumated for anywhere from several weeks up to six months! 

North American colubrid breeders typically keep their snakes in brumation for around three months. Leopard geckos are typically in brumation for thirty to ninety days.

Brumation In Captivity vs. In Nature

Regardless of the natural processes of brumation, since you're in control of your animal's environment, you may be able to start and end brumation whenever it works for you, and you could probably shorten it so that it has less impact on your reptile's health and weight.

Captive Brumation

This will only work if your pet is not "in tune" with the seasonal changes outside of your home, meaning that your home's temperature stays consistent year-round, and there are no open windows that allow natural sunlight. Captive brumation also enables you to control the temperature to the ideal range—low enough to avoid encouraging the animal's metabolism, which would cause drastic weight loss, and high enough to prevent freezing the poor thing.

Another advantage of brumation in captivity over brumation in the wild is that you can control food and water availability. In the wild, a snake may mistakenly eat a prey item too late in the year, right before it gets cold. Unfortunately, the snake wouldn't be able to digest the food, and it could very likely rot in its body and kill it.

Water also tends to freeze over during the Winter, making it inaccessible to the local brumating snake population. It's vitally important to always have water available for your reptile while they brumate because they can quickly become dehydrated in the low temperature and humidity. Some keepers even choose to soak their animals weekly to encourage hydration and elimination. This is also a great time to check your reptile's weight and make sure that they aren't losing too much.

Natural events such as dangerous temperature highs or lows, flooding, and predation are, of course, avoided completely when brumating in captivity.

Brumation in Nature

In the wild, brumation is typically triggered by shorter days, lower temperatures, and barometric pressure and humidity changes, depending on the species and the native environment. Most keepers that choose to replicate brumation in captivity prefer to artificially create those changes as closely as possible.

Wrapping Up Brumation in Reptiles

If you’ve made it this far through the article, you’re likely in one of three scenarios:

• You’d like to brumate your reptiles for breeding purposes.
• You’d like to brumate your reptiles to replicate their natural life and take advantage of potential longevity and health benefits.
• Your reptile didn't give you a choice! Their natural instincts kicked in, and they entered brumation without any (intentional) environmental changes.

Whatever the case may be, good job taking the initiative to learn about the history and proper implementation of this natural survival process.

Equipped with this knowledge, you’ll be able to make an educated plan for inducing brumation and make sure that your pet is healthy enough to undergo the process. Try not to miss them too much—it’ll only be a few months!

Stacey is a lifelong reptile lover, caretaker, and author at Reptile Guide