Caring for a tortoise is not an easy job and you may be wondering if your reptile companion can withstand every aspect of the weather where you live or whether they might be in danger of freezing to death if things get too cold? Here’s what you need to know.
Can a tortoise freeze to death? Tortoises can freeze to death. A tortoise is a cold-blooded animal and in the wild, they tend to hibernate through winter to avoid extreme cold. If the temperature drops too low for too long, whether or not the tortoise is in hibernation, she can freeze to death.
Approximately 45 to 55 degrees Fahrenheit / 7 to 12 degrees Celsius can be considered cold for tortoises. Anything below is very cold and can become dangerous. Let’s see what tortoise owners like us can do to ensure our beautiful pets do not freeze to death. The good news is that for a pet tortoise, at least, you can hugely reduce the risks with some very basic precautions.
The Tortoise’s Heating System (or Lack Thereof)
A tortoise is an ectothermic or poikilothermic (depending on whether you like Latin or Greek more) animal as are all reptiles. That means that your tortoise is cold-blooded and as such it is unable to produce any form of heating within its own body.
This is why, for the most part, reptiles tend to be found in countries with warm climates. As you will know from watching your tortoises, they like to bask out in the sun during the day and this helps them to stay warm.
However, they can’t stand extreme heat and when things get too hot, they have to move into shade because not only can they not generate any heat in their bodies, they have no power to cool themselves down.
A tortoise maintains thermoregulation (that is it keeps a healthy balanced temperature) in the wild, by moving in and out of sunlight all day long. Pet tortoises do the same thing if they are free to roam outside and if they are kept indoors they need to have heat and UVB (ultraviolet-B light) to simulate the outdoor weather.
When your tortoise is allowed to maintain its body temperature like this, its blood temperature is roughly the same as a human being’s.
However, when the temperature drops (either at night, with a change in weather or change in season) the tortoise cannot sustain this temperature and its blood temperature begins to fall.
What Happens To A Tortoise When The Temperature Falls?
Well, it depends on how far the temperature falls and for how long. It is worth noting that tortoises are burrowing animals and if they are in their natural environment, they will simply retreat to their burrows and wait for the change to pass.
So, whether it be a brief storm, the arrival of night, or the beginning of winter, the tortoise will head down in their burrow to escape. By moving underground, the tortoise benefits from the radiated heat of the earth whilst being protected from the extremes of the weather such as frost and wind chill.
Torpor A (Hopefully) Temporary Reaction To Cold
They may also enter a state known as “torpor” when they are cold and it is very clear that the animal isn’t at its peak performance, they move sluggishly and they lower their breathing, heart and metabolic rate to enable them to conserve energy and prevent themselves from coming to harm.
Torpor is a survival technique and it comes at a cost. While it is used to protect the tortoise from extremes of cold, the price for it is that when the tortoise warms up again, they must expend quite a lot of energy to “come back online” fully.
You will see a tortoise arousing itself from torpor with shaking and muscle contractions that can last up to an hour. This is quite normal and it’s part of the process. While this demands quite a bit of a tortoise’s energy, the expectation is that it won’t cost as much as they saved while in torpor.
However, a tortoise cannot enter torpor forever, if the environment does not warm up or the temperature falls too low (it appears that 2-5 degrees Centigrade is about the minimum a tortoise can take for very long) then the tortoise will eventually freeze to death as even in the torpor-state it is still using some energy.
Thus, while torpor is fine for weathering a storm or for getting through a chilly night, it’s not going to help your tortoise get through winter.
What Happens To A Tortoise In Winter?
As a general rule, it’s a good idea to move your tortoise inside for the winter, if you live in a area with a cold winter. This would apply to most people outside of tropical or equatorial zones and may still apply in places within those zones.
Then you need to determine whether your tortoise is a hibernating breed or not. You see not all tortoises hibernate for the winter, in fact, tropical tortoises generally don’t because in the wild, their habitats are never cold enough to require hibernation.
Those from more temperate zones such as the Mediterranean, for example, will hibernate if given the opportunity to do so.
In order to work this out, you should know the exact species and the sub-species of your tortoises. You don’t want to assume that a tortoise will hibernate if it doesn’t or vice-versa as your decision to help or prevent hibernation might have serious health implications.
Moving your tortoise into your home for the winter removes the likelihood of it freezing to death. However, there’s still some work to be done to ensure that the tortoises remain healthy while they are removed from their usual home.
So, What To Do With A Non-Hibernating Tortoise In Winter?
If your tortoise doesn’t hibernate then you need to keep it in the home and in a strictly temperature controlled environment.
The temperature during daylight hours for these tortoises needs to be above 84 degrees Fahrenheit (that’s 28.8 degrees Celsius) but the nighttime temperature should be reduced to no less than 54 degrees Fahrenheit (that’s 12.2 degrees Celsius).
To achieve this, you need to keep measuring the temperature within their vivarium or other enclosure. You cannot rely on measuring the temperature in the larger room as they will vary.
You also need to ensure that during the day that tropical tortoises have access to UVA and UVB light. Without this, they will struggle to properly metabolize the nutrients in their diet and will become quite sick.
Depending on where you are in the world, you may need to treat your tortoise’s “winter” as anything from 3-6 months long in these circumstances. Readers in the UK will want to aim for the 6 month mark, while those in the mid-West of the USA, for example, can probably reduce this to 3-4 months.
What To Do With A Hibernating Tortoise In Winter?
Well, it depends on the condition of your tortoise. While hibernation brings many benefits to your tortoise there are some warning signs that you should involve a vet prior to hibernation.
Related article: Is my tortoise dead or hibernating?
You should always check the following prior to allowing a tortoise to hibernate:
- The tortoise is of a normal weight and has been eating without issue
- The tortoise has a dry nose and there is no sign of it wheezing when it breathes
- The tortoise has clear eyes with no discharge apparent around them
- The tortoise has flat ears with no marks or discharge apparent
- The tortoise’s mouth is the usual color and is not covered in spots
- The tortoise has no lumps or swellings on the tail or legs
- The tortoise’s poop is regular and firm and there is no indication of diarrhea
- The tortoise has no obvious signs of injury, distress or disease
You should always refer the tortoise to a vet if it does not meet these criteria. It is very important to note that an underweight tortoise should not hibernate under any circumstances, they may not freeze to death while indoors, but they can still starve to death.
What Are The Reasons To Let My Tortoise Hibernate?
There are solid reasons that a tortoise hibernates:
- A tortoise that does not hibernate may become lethargic
- A tortoise that does not hibernate can have trouble mating
- A tortoise that does not hibernate is more likely to have health problems late in life
- A tortoise that does not hibernate may not be able to get a suitable diet in the winter (though this is less problematic in an age of global convenience)
Basically, if your tortoise comes from a breed which hibernates – it’s meant to hibernate, and its health and wellbeing will benefit from doing so.
The Risks Facing Hibernating Tortoises
Unfortunately, hibernating your tortoises is not a risk-free prospect. In fact, you have to be very careful, indeed, or you may do even more damage to the tortoise than you had intended to prevent.
If the tortoise hibernates outdoors it faces three natural risks:
- It may freeze to death. The tortoise needs a temperature of around 38 to 48 degrees Fahrenheit to make it through hibernation. If they go below 38 degrees for any appreciable length of time – they can freeze to death. Even if they don’t die, these temperatures may leave them blind or cause tissue damage which is permanent.
- It may drown. Tortoises hibernate in burrows outdoors. These are designed to protect them from water but in the event of a severe downpour, their defenses may not be enough, and they can drown.
- It may get eaten. Predators aren’t experts at getting in burrows, but they can stumble across them and decide to have a go anyway and a sleeping tortoise isn’t built to fight anything off.
That means if you do decide to let tortoises hibernate outside, you should make sure there is no chance of a frost, of heavy rain storms and that there is some security around the area to prevent predators (particularly rodents) from getting to the hibernating tortoise(s).
There are also risks if your tortoise hibernates indoors all of which can be prevented:
- It may freeze to death. While putting a tortoise in a refrigerator is an excellent way to help it hibernate at a steady temperature. If the external temperature falls to low, the tortoise can still freeze to death.
- It may die of dehydration. You must give your tortoise regular soaks and ensure it has been fully watered before it is allowed to hibernate. Your tortoise should have empty bowels when it goes down for the winter, but it should also have a full bladder. If you discover that a tortoise has urinated while hibernating, it should be gradually woken in a lukewarm bath and be rehydrated and then kept awake (using an artificially created simulation of summer) for the rest of the winter.
- It may die of dehydration. Weigh your tortoise every week while it hibernates. If it’s losing body weight at a rate of more than 1% every month, you need to wake it (using the method above), rehydrate and then keep it awake.
- It becomes too warm. Conversely, raising the temperature on a tortoise too much (anything over 52 degrees is a problem) can make the tortoise burn through its reserves too quickly and it can become sick or die. This is why refrigerators are often the perfect place for hibernating tortoises.
- It ferments to death. We said earlier that a tortoise should have empty bowels before it hibernates and that’s because any food in the stomach can end up fermenting and creating toxins that kill the tortoise. It’s recommended that you don’t feed a tortoise for 2-4 weeks before they hibernate to ensure they are safe.
How Should A Tortoise Hibernate So That It Doesn’t Freeze To Death?
There are three methods of hibernating a tortoise: refrigeration, the box method and the natural method.
The Refrigerator Method
This is our favorite way to do it. Place your tortoise in a box (with air vents – it needs to breathe) in a temperature controlled refrigerator set to 5 degrees Centigrade. Put a digital thermometer inside the fridge to check the temperature and adjust as required.
You must return to the fridge daily and open the door to allow some fresh air in. If you can’t do this, the alternative is to snip away some of the seal on the fridge door and run an air pump through the gap.
You must, as we said, earlier ensure that the room with the fridge in never falls below 5 degrees too. A refrigerator can only cool things down, it can’t warm them up – so if the background temperature drops below the internal temperature of the fridge, the internal temperature will match the background. Your tortoise can and will freeze to death if the temperature drops too low.
The Box Method
The box method requires that you buy a Tupperware box, make some holes in the lid for air, and place the tortoise inside Then you place some insulating material around the box (like dry soil or compost) then you place this box inside a bigger (it’s best if this is wooden) box filled with either newspaper (which should be tightly packed) or polystyrene chips.
Then you monitor the temperature of your tortoise daily using a digital thermometer (probe should be in the Tupperware box from the start) and ensure it stays safe. You can then put the box in an outbuilding or the garage or even in a cool spare room.
The Natural Method
Do not choose this method unless you live in a sub-tropical zone where winters are very mild. In this case, you prepare a tortoise for hibernating (starve them prior to the hibernation and bathe them) and then let them do what comes naturally.
You won’t be able to monitor them once they are in the burrow, so, you will just have to cross your fingers that everything will be OK. Make sure to secure the area against predators though as this can drastically improve their survival chances.
Can a tortoise freeze to death? Tortoises can freeze to death but there is no reason for pet tortoises to suffer such a fate. Pet tortoise shouldn’t freeze to death as long as proper care is given. Hibernating outdoors in temperate regions is a risky proposition and even if your tortoises don’t hibernate, they should spend the winter indoors if it’s particularly cold outside.
Fortunately, a hibernating tortoise requires very little effort to keep safe and the best way to do this is to keep him, her or them in the refrigerator in a safe and sensible fashion.