Hibernation among turtles is generally determined by their geographical range. Turtles that are originally from temperate climates generally hibernate.
Hibernation is encouraged by breeders as it may increase the likelihood of breeding. However, your turtle doesn’t need to hibernate. Technically, turtles do not hibernate, they brumate.
For the purpose of this article, we will refer to the long periods of dormancy during the wintering months as hibernation.
It is important to take all the necessary precautions before, during, and after hibernation. Additionally, unhealthy turtles should not hibernate.
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Turtle Hibernation Guide
Why should you allow your turtle to hibernate?
According to many breeders, hibernation (brumation) increases the chances of successful breeding. This is one of the reasons why many hibernate their turtles.
Another reason to hibernate your turtles is due to a lack of space and turtle setups inside. This is particularly true for outdoor turtles.
If you have your turtles set up outside, you may not have the facilities and space inside to care for them during the wintering months.
If this is true, then you will have to allow them to hibernate through winter. Hibernation requires very little space and resources as the turtles will be inactive.
If you don’t bring the turtles indoors to hibernate then they will do it outside.
As you can imagine, this is riskier as the turtle may fail to find a suitable hibernation spot. Likewise, they will be left exposed to unpredictable weather.
Even when allowed to hibernate indoors, there are still risks involved. Not all turtles survive hibernation.
Because of the risks associated with hibernation, we don’t recommend it if your turtles are already maintained indoors and you don’t want to breed them.
As long as indoor temperatures remain constant through winter, the turtle will not hibernate. It may be less active and eat less, but it will be safe.
Preparing for hibernation
Not all freshwater turtles hibernate. You need to know if your turtle hibernates or not. This is to avoid any unnecessary deaths.
The closer the geographical range of the turtle species is to the equator, the less likely it is that the turtle hibernates.
As such turtles endemic to the tropics such as the African sideneck turtles (Pelusios castaneus) don’t hibernate.
The Asian box turtle also doesn’t hibernate. If your turtles don’t hibernate, then they must be kept warm throughout winter.
Some common turtles kept as pets that hibernate:
- Map turtles (Graptemys) including but not limited to northern map turtle (G. geographica), Barbour’s map turtle (G. barbouri), false map turtle (G. pseudogeographica), and Mississippi map turtle (G. p. kohnii)
- North Mud turtles (Kinosternon) including Striped mud turtle – (K. baurii), Yellow mud turtle – (K. flavescens), Eastern mud turtle (K. subrubrum)
- Musk turtles (Sternotherus) including common musk turtle (S. odoratus), and razorback musk turtle (S. carinatus)
- Red-eared sliders (Trachemys Scripta Elegans)
- North American softshell turtles (Apalone) including the Florida softshell turtle (Apalone ferox)
- Snapping turtles (Chelydra serpentina)
- Spotted turtles (Clemmys guttata)
- Wood turtles (Clemmys insculpta)
Perform a health check
Of course, only healthy adult turtles should be allowed to hibernate. Sick turtles usually don’t survive hibernation.
Signs to watch out for include runny eyes or nose, wheezing, coughing, difficulty breathing, discharge from the mouth, cloaca or mouth, low body weight, basking all the time, cuts, wounds, and shell rot.
Even if your turtles looks healthy, you can have a vet or a hero expert inspect them.
It’s not advisable to allow hatchlings and subadults to hibernate as the survival rates among younglings is less than that of adults.
Make sure to hibernate turtles only if you can check all of the boxes below:
- Healthy Turtles
Your turtle(s) must not be suffering from any kind of illness or disease to hibernate. Check for head swelling, open wounds, dry or flaky skin, white or light-colored tongue, and other abnormalities.
Your turtle(s) must not be less than one year old to hibernate.
- Safe space
Secure a space for them to hibernate without any potential threats. Ensure that no predators can reach the location and that the environment is suitable for them.
- The temperature
The temperature at the beginning of September or October must be around 50 degrees Fahrenheit, which would be ideal for turtles to go into hibernation.
Decide where and how your turtle will hibernate
Freshwater turtles prefer to hibernate underwater. If you have a garden pool, then the turtles may hibernate in this pond.
If you want to hibernate your turtle this way then you need to winterize your pond for the turtles. This can be quite expensive though.
Winterizing your pond for the turtles
For starters, the pond needs to have a large surface area and be several feet deep. The depth allows the water at the bottom of the pool to be relatively warm.
As such, when the surface freezes over deep down, the water in the pond will be quite warm (about 35 to 50 °F).
If the pond has water features, turn them off as these features circulate the water and significantly lowers the water temperature.
A submersible pond heater can also help keep the water temperature at the bottom of the pond between the required temperature range.
Hibernating turtles can remain underwater for several months as they can absorb oxygen through their mouth or cloaca depending on the species.
As such, the pond needs to be well aerated. Increase oxygen levels by creating and maintaining an air hole in the ice.
Consider installing a floating heater or pond de-icer to keep this airhole always open. A large surface area also ensures that the exchange of dissolved gases between the pond and outside air is high.
Don’t worry when the air hole freezes over during extreme cold spells as they will reopen again after a few days.
Remove every bit of decaying vegetation such as fallen leaves, branches, and such. These can massively influence the pH level of the water as well as the water quality over the winter.
As you can imagine, winterizing a garden pond can consume a lot of electricity and as a result, can be an expensive process. It is also quite unpredictable.
Using a Hibernation tank
A hibernation tank can be set up inside (preferably in the garage, basement, shed, or barn). A hibernation tank gives you better control over the hibernation temperatures as well as the oxygen levels in the tank.
This is simply a large tub or bin which can hold all the turtles comfortably.
You may add bedding, just in case the turtle wants to bury itself or even lay on top of the substrate while it hibernates. This bedding can be composed of sand such as Exo Terra Riverbed Sand.
Fill the tub with dechlorinated water. This can be water from your garden pond.
Install an aquarium filter such as the Marineland Penguin Power Filter., air-stone such as the Tetra Whisper Air Pump, and a submersible heater such as the Orlushy Submersible Aquarium Heater to keep the water temperature from falling too low.
The recommended hibernating temperature is 40°F (4.5°C). The temperature must not fall below 35 °F.
I recommend a low of 37 °F. The aquarium filter and airstone ensure that the water is well aerated and clean.
Some breeders even have hibernation tanks with a raised platform (with a shallow indentation) filled with moist leaves that the turtles rest in when they want to.
Different turtles hibernate for different lengths of time. Most turtles hibernate for two to four months. Some turtles such as the eastern mud turtle can hibernate for up to 6 months.
Hibernation length all depends on the temperature outside. Once the temperatures outside are warm enough then hibernation should end.
Feed your turtle foods high in vitamin A
It is necessary to keep the vitamin A levels high as the turtle will lose a lot of vitamin A while hibernating. Learn more about vitamin A deficiency here.
About 16 weeks to hibernation, increase the vitamin A content in the turtle’s diet. You may already be feeding your turtle foods high in vitamin, if so then continue as usual.
Some plant foods high in vitamin A include kale, collard greens, dandelion, alfalfa, carrots, cantaloupe, peaches, broccoli, squash, and mustard. Try to minimize the amount of fruits to about just 10 percent of the turtle’s diet. Rely more on leafy greens.
Fish and pinkie mice are also high in vitamin A.
Fasting the turtle
About 7 weeks to hibernation (late July), switch to a high-fiber diet if the turtle is herbivorous.
Start to fast the turtle about 2 or 3 weeks before hibernation. This should allow any food in the turtle’s digestive tract to digest before hibernation. Undigested foods in the digestive tract can decay during hibernation and can cause infections.
For instance, if you see the turtle eating a week before hibernation, then you have to move the date back to allow the food to properly digest and leave the digestive tract.
Weighing the turtle
The turtle should be weighed right before hibernation. Now keep track of the turtle’s weight. Every 2 or 3 weeks, weigh the turtle and track its weight.
The turtle should not lose more than 1% of its total body weight. To ensure that the measurements are precise enough use a digital scale.
If you notice that some turtles have lost more weight than they should, take them out of hibernation. You can keep them in a turtle tank over the winter. Slowly try to warm them up for one week. You can even take them out and soak them in tepid water once a week for the first month. Make sure to check on them every once in a while!
Lower the temperature gradually
A week before hibernation, the temperature within the hibernation box should be about 65°F (18°C) for two days.
Over the next two or three days gradually reduce the temperature to 60°F (15°C). Then over the next 2 or so days reduce the temperature to 50 °F (10°C).
Start the hibernation process
You can either decide to hibernate the turtle in a hibernation tank (hibernaculum) or an outdoor pond. Prepare each hibernation location as described in the section – Decide Where And How Your Turtle Will Hibernate.
Inspect the turtle regularly
The turtle needs to be monitored closely, every two or so weeks, physically inspect the turtle, and make sure that it’s healthy and safe. Check for signs of infections. Also, if the turtle defecates while hibernating, something might be wrong.
Bring the turtle out of hibernation, if it loses too much bodyweight, defecates, or shows signs of illness.
About Fridge hibernation
Fridge hibernation may work for tortoises and box turtles but not freshwater turtles.
While the temperatures in refrigerators are ideal for freshwater turtle brumation, one of the main problems encountered is the lack of oxygen in the water.
Many freshwater turtles hibernate underwater and absorb oxygen from the water. In a fridge, this can be a problem. You may be able to remedy this by using a really large tank and large volumes of water.
However, we don’t recommend hibernating a freshwater turtle underwater in a fridge. Since aquatic turtles need to be underwater to hibernate, it seems refrigeration hibernation isn’t an option.
Once hibernation is over, gradually increase the temperature within the hibernation tank. Increase the temperature to 60 °F for a couple of days, then increase it to 65 for the next couple of days before you return the turtle to its usual enclosure.
For turtles that hibernate outdoors in a pond, once temperatures are high enough, hibernation will end. Check on your turtle and make sure it’s okay.
How Do Turtles Survive Hibernation?
Turtles have lungs and breathe just like humans, which raises the question: how’s it possible for them to survive in a frozen pond?
The answer is relatively simple. Turtles are ectotherms, which are basically organisms whose bodies can adapt to external temperature. Therefore, if you put a turtle in a cold pond, it will adjust its body temperature to survive the cold.
The other logical question commonly asked is: How do they not starve or drown?
Turtles hibernating in cold weather have a significantly slower metabolism. This means that they need less energy and less oxygen, as they rely on the reserves. Therefore, they don’t have to use their lungs for breathing.
On the other hand, a very unusual vascularized body part on turtles is their butts. This is technically called cloacal respiration. Turtles get most of the oxygen they find under the water through their rear ends.
However, you should keep in mind that even turtles have their limits. Their body temperature cannot go below freezing points as they cannot handle ice crystals on their bodies.
Freshwater and ponds have a relatively stable temperature, which is why it’s easy for turtles to hibernate in these spaces.
What Issues Can Turtles Experience?
Two central problems that turtles face while hibernating underwater is the following:
- Not enough oxygen gets into the water
- They cannot surface to breathe
Therefore, turtles are pretty much stuck the way they are. Some turtles can handle the lack of oxygen, whereas others cannot.
Snapping turtles and painted turtles can switch their metabolism and function without oxygen. However, this can be dangerous for them, and they can usually only last up to 100 days living that way.
After hibernation, they’re pretty much one big muscle cramp. It takes them a lot of time to adjust back to the regular environment, and they need a lot of sunshine. As they go through this process in the spring, they’re open prey to predators, which means that the post-hibernation period can be pretty dangerous for turtles.
Turtle hibernation or better still winter cool-down is not needed for pet turtles to survive.
Wild turtles hibernate to survive the winter since there is less food and temperatures aren’t high enough to enable a fast metabolism.
When it comes to pet turtles, this isn’t a problem as you can provide the food and regulate the temperature.
However, if you must allow the turtle to hibernate, it is important to take all the necessary precautions. I recommend allowing your turtles to hibernate indoors inside a hibernation tank as this is safer and generally cheaper.
You can allow your outdoor turtles to hibernate within their pond however, you may need to install a submersible pond heater to keep the temperature between 35 and 50 °F.
Also, you may need to use a de-icer to keep an air hole open if the pond’s surface freezes over. Since maintaining the heat requirements can significantly affect your monthly electricity bill, an indoor hibernation tank may be the cheaper option.
If you have any questions or experiences to share, we’d love to hear them.