How Turtles Hibernate Through the Winter

by Mary Hopson


This is Nicky.

She is a kind of water turtle called a river cooter. She has been my pet for 32 years. In the picture, she is sitting in the sun to warm herself.


Temperature is important to turtles. Turtles are ectothermic animals. That means they get their body heat from their surroundings--the air, water or ground. They need to be warm to move around and eat. If they get too cold, everything in the body will slow down. Then they can't eat and digest food. The heart slows down and the lungs do too.

Some turtles live where it is warm all the time. They stay active all winter long. But turtles who live where it gets cold and snowy have a way to keep themselves alive. They can hibernate. (Some people use the word "brumate" for what reptiles do. Mammals hibernate. But most people use the word hibernate anyway.)

Different kinds of turtles hibernate in different ways. Most water turtles go deep into the pond and snuggle down into some mud and leaves at the bottom. Then they let themselves get cold. Their bodies slow down so they don't need to eat anymore. Their hearts slow down too so that they beat only once every few minutes. They stop breathing through their lungs. Because their bodies are running at such a slow speed, they don't need much oxygen, but they do need some. They can get the small amount of oxygen they need from the water. It sinks in through some specialized skin cells that are just inside the tail opening. That's right! They "breathe" through their tails! Water turtles can stay like this for two or three months.


These 2 turtles are named Vincent and Sien. They are box turtles. They are called that because they can go inside their shells and then close up the lower shell to completely cover the head and

tail. They can "box up" for protection. (To see how it works, click here.)

Box turtles don't stay in the water much and they don't hibernate under water. But box turtles, and other turtles that stay on the land most of the time, can hibernate too. They dig a deep burrow into the ground. They dig as deep as they can.

When turtles are hibernating, they are in danger. They are not able to run away from animals that might want to eat them. They try to find a place that will be safe from predators like dogs or raccoons. Another bad thing that can happen is that they can freeze to death. If the water in the pond freezes all the way down to the bottom of the pond, the turtles that are hibernating there will die. If the ground freezes deeply around hibernating box turtles, they will die too. But that doesn't usually happen. If a pond is deep, only the top part of it will freeze solid and there will be water underneath the ice. Then the turtles will be safe. And the box turtles are usually safe too, because only the top layer of the ground will freeze. The turtles will stay deeper down where the dirt doesn't freeze.

Thousands of turtles prepare for winter by going deep into the water or by digging a deep burrow. They will slow down and hibernate for as long as the weather is cold. Then when the spring comes, the turtles will warm up and become active again. Once again, they will look for nice warm places to sit and enjoy the sun.


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Kids Questions About Turtles