When we think of winter, we think of polar bears, hot chocolate, and ice skating on frozen lakes. We rarely associate the frosty time of year with snakes, turtles, and lizards. But every summer, without a doubt, they are here in numbers. How do these cold-blooded animals, who rely on their environment to maintain their temperature, survive during these harsh weather conditions? This article will showcase how these animals have adapted unique survival techniques to get through the freezing temperatures they face.
We know that some mammals like bears and squirrels will fatten up before the winter and then fall into a deep sleep only to emerge at the start of spring; this is called hibernation.
Reptiles have adopted a similar technique but with some subtle differences. The reptilian version of hibernation is known as brumation. The first big difference is that if the weather is suitable in brumation, cold-blooded animals will awaken from their cryogenic state. They will hunt for food, drink water, and even bathe in the sun to regulate their temperature.
Because cold-blooded animals rely on their environment to maintain their body temperature, brumation can happen sporadically at any time of the year if the weather permits, unlike hibernation, which is a scheduled event in the mammal community.
Brumation is used to slow down metabolism, the heart, and respiratory systems to maintain their dormant state for extended periods.
Now that we have established what brumation is, let's see how the cold-blooded animals who live on land use this and other techniques to survive.
The animals who live on land need to find shelter during wintertime, and they do so by finding burrows and other crevices, anything from piles of leaves to caves, to retain heat.
They will then enter their brumation period, slowing down all functions and remaining dormant until the weather provides adequate heat. This awakening can happen at any time throughout the winter, unlike hibernation.
While the brumation slows down their metabolism, they still need to drink water from time to time, so it makes sense that they can enter brumation at will.
Snakes are an interesting cold-blooded character when it comes to this because, unlike other reptiles, they will return to their same burrows year after year. They will also share their lairs with other snakes. This gathering helps them retain heat. The more snakes, the better heated the den will be.
Wood frogs are also a particular case as they will become frozen in a cryogenic state, functionally dead, and dethaw when the spring provides and continue with their lives.
Isn't the animal kingdom amazing?
The cold-blooded animals that inhabit our lakes, rivers, and oceans have different challenges to survive the freezing conditions of winter compared to their land-dwelling counterparts.
The first difference is that there are fewer burrows in the water than on land, so these creatures have different ways of dealing with that. Fish, for instance, will find deeper waters that maintain their warmth.
Other amphibians and reptiles will cover themselves in mud or, in the turtle's case, sink to the bottom of their water source and begin the brumation process.
These deeper waters provide less sunlight, and with sunlight being the source of increasing a cold-blooded animal's metabolism, it is a helpful hand in maintaining the dormmate state.
But not all cold-blooded animals have gills, so how do they stay so long underwater without oxygen? This problem is solved in a couple of different ways. Turtles can absorb oxygen through their skin, specifically their tails, so when the water moves over them, they can breathe right through their skin. As the picture above shows, alligators will break the ice and stick their snouts out before entering the catatonic brumation state.
And finally, the other adaptation used is eating a lot before going into brumation. Unlike in hibernation, where mammals do this to store fat, cold-blooded animals will do this to store glycogen which acts as an antifreeze inside their bodies!
The adaptations that these aquatic creatures have evolved are mind-blowing.
Insects are a fascinating circumstance when it comes to cold-blood winter survivors. Many insects have a short life span, so surviving is not necessarily their goal. Their goal is to breed and lay as many eggs as possible to let their bloodline live on. In this case, many insects will lay eggs and die off when the cold comes.
Instead of brumation, insects will enter a state known as diapause.
Diapause is when the cold-blooded bugs will maintain their same state and wait to develop until warmer months arrive. This means larvae or eggs will stay larvae or eggs until the weather gives them the go-ahead to grow up.
There are other approaches used by insects to battle the elements. The monarch butterflies have been famously known for their large population migrations.
Many insects will go out of their way to ingest prey with high sugar values to produce glycogen and glycerol to act as antifreeze. Some insects will even dehydrate themselves without enough water to freeze inside them.
Regardless of how they do, insects and other cold-blooded animals have built serious defenses to survive the winter months.