Turtles are very hardy and adaptable animals, but what’s their limit? Can they freeze and stay alive?
Can turtles freeze and stay alive? Under normal circumstances, turtles cannot stay frozen for long periods of time and stay alive. If a turtle freezes completely ice crystals will form in its internal organs which will damage them.
So turtles can’t really freeze and stay alive, but there is an exception to this.
The Exception
If turtles are in shallow waters and ice forms on the surface of their shells they can still remain alive, but not for very long periods of time. Thin ice on the top of the shell won’t be a problem if removed quickly. But if the turtle remains trapped in ice, crystals will start to form inside the turtle’s body.
Now you might be wondering, what do turtles do in the winter? Don’t they hibernate underwater?
Hibernation
First, let’s see what hibernation actually means. Hibernation is a state in which some mammals and reptiles will enter during cold periods. When they are in this state, they will reduce their metabolic rate, which means that they will use less energy, they won’t require any food or water, and they will sleep the whole time.
That is the basic explanation of what hibernation means. While this explanation covers the basic facts it doesn’t explain how it actually happens, and it doesn’t cover the different things that only certain species can do. So let’s move on to turtles and see how they do it.
How Turtles Hibernate
Unlike most animals that hibernate, turtles are reptiles. And this means that they are cold-blooded animals. Cold-blooded animals are not able to generate body heat and they rely on the surrounding temperature to heat their body. So turtles will observe very easily subtle changes in the temperature.
When the weather starts to get cold the metabolism of a turtle will automatically start to slow down. And as a result, their hearts will start to slow down, along with all other processes that happen in their bodies.
In general, the heart of a turtle beats between 40 and 45 times per minute, when they hibernate they will slow down to around 10 beats per minute. This should give you an idea of how much they slow down during hibernation.
As a result of this slow down they will need considerably less oxygen, sometimes due to unfortunate situations turtles don’t have access to oxygen at all, but because they are hibernating they are able to live without oxygen for up to 5 months. They can also survive for 5 to 8 months without any food or water. The amount of time they can do those things varies from species to species, the numbers that I gave you are just some averages.
The fact that turtles don’t need to generate heat to warm their bodies is also very helpful for them because, unlike mammals that hibernate, turtles don’t need to use energy to warm their bodies. This also means that they have to be very careful with the place where they choose to hibernate. So the fact that they are cold-blooded has its advantages and disadvantages when it comes to hibernation.
Turtles are able to do all those amazing things because they reduce their metabolic rate. But reducing the metabolic rate can also have some unpleasant side effects. One of the bad things that happen is that they have a hard time getting rid of the lactic acid that accumulates. Lactic acid is the same thing that gives us muscle soreness, so you can imagine how unpleasant it can be for the turtle to wake up after a long sleep with muscle cramps all over the body.
To neutralize the lactic acid turtles use magnesium and calcium that they’ve stored in their shells. If they didn’t do that the lactic acid build-up would be too big, and they wouldn’t be able to wake up from hibernation at all.
The calcium and magnesium that they used would have helped them grow, but because getting rid of the lactic acid was more important they had to use it for that. This is another bad side effect, turtles won’t be able to grow when they hibernate. And growing isn’t something superficial for turtles, it’s something that can save their life. The bigger they get the fewer predators will come after them.
But in the end, even if they don’t grow it was definitely worth it because they managed to survive the winter.
Now let’s take a closer look at the specific things that aquatic and land turtles do when they hibernate.
How Turtles Hibernate Underwater
In general, most turtles are able to spend around 30 minutes underwater before they have to come out for oxygen. But when they are hibernating they are able to spend months underwater without having to come out to get oxygen. The reason why they are able to do this is that they have a cloaca.
The cloaca is the posterior orifice that serves as the only opening for the digestive, reproductive and urinary tract.
The main way a turtle breaths it’s through its nose, all turtles have two small holes on their face that act as any normal nose would, when it comes to breathing, and of course they have two lungs where the air is transported. Until now there is nothing different in the way a turtle is breathing than the way you and I are breathing, they inhale air into their lungs and then exhale it, but the way things work on the inside is completely different.
When you inhale air, you can observe that your chest becomes smaller and when you exhale it becomes bigger, this happens because you have flexible ribs, turtles on the other hand have a shell that is not flexible at all. Since turtles don’t have this flexibility they have no use for the lung and muscle setup that we and most mammals have. Instead, turtles have muscles that pull the body outwards, towards the opening of the shell, to allow it to inhale, and more muscles to squish the turtle’s guts against its lungs to make it exhale.
The cloaca works in a similar way to the lungs, when the turtle is inside the water the cloaca will act like a pump that will suck water inside and after it gathers all the oxygen from it, it will expel the water out, and then it will start over. Due to the way things are arranged on the inside of the turtle this process is less exhausting than normal breathing.
Even if using the cloaca is less exhausting for the turtle, in normal circumstances a turtle won’t be able to survive for long periods of time using only the cloaca. But when they hibernate they need considerably less oxygen, and the cloaca can produce that amount without too much effort.
So the cloaca is the perfect mechanism for hibernating turtles, it requires very little energy to function, and it provides the exact amount of oxygen.
If you own an aquatic turtle and you want to see your turtle using its cloaca to breathe, you can easily do so. Just look at the back end of the turtle when it’s swimming around, if you spend 15 minutes looking you have pretty big chances of seeing it in action.
You can find more information about the cloaca in this article if you want to know more about it.
But to be able to use the cloaca, the lake, or pond where they hibernate must have oxygen in it. So if the surface completely freezes over the oxygen in the water will probably be gone in a month or two, and this is not a great situation for most animals that live in that lake.
But as I’ve mentioned before turtles are able to survive months without oxygen so even if the oxygen from the water is completely gone they should still be able to survive the winter.
I’ve mentioned before that turtles also like to hibernate in mud. This is because mud can offer them protection from the cold weather and protection from predators.
When choosing a place to hibernate turtles will be interested in two things. Protection from the cold weather and protection from predators.
Usually, a lake or a pond will offer them the best chances to survive. But this doesn’t mean that every hole in the ground with some water in it is good. Turtles choose to hibernate in water that is deep enough so it won’t freeze completely. Turtles are able to survive in harsh conditions, but they have their limits, and being frozen for long periods of time is one of them.
Conclusion
So turtles are not able to stay frozen for long periods of time. But in some cases, if the ice formed on them is really thin, they can be saved.
And while hibernating turtles don’t really freeze underwater, they stay at the bottom of the lake where the water is slightly warmer than at the surface where ice forms.
This article should have answered all your questions about freezing turtles, but in case you have any questions left, please feel free to leave them in the comment section where I will gladly answer them as soon as possible.
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