Hibernation in Animals and Its Biological Mechanism

There are different ways of adapting to the drastic changes in the weather conditions that animals perform to escape the lack of food and activities. One of the best methods is hibernation. It is a process where the metabolic conditions suspend to a minimum level resulting in an escape from the extreme winters for months. Here, we will study how these animals hibernate and what is its difference from aestivation.

The special process of suspending the metabolic activities by staying inside a nest or den and going to deep sleep to avoid the extreme weather conditions in winter is called hibernation. It is a technique where the insects and animals learned how to survive the chilliest days and nights without foraging or predating outside and stay inside their nests. They don’t need to migrate to someplace warmer to stay, rather trim down the basic metabolic activities to the lowest and conserve energy to survive for months.

In this aspect, animals often do the same thing to overcome the harsh climates of summer in arid regions. They also suspend their metabolic activities and conserve water to survive harsh summers. This process of survival is called aestivation. With this unique physiological phenomenon, animals and insects escape the lack of food, drought, and extreme heat. We will discuss the difference between hibernation and aestivation later.

(Image will be Uploaded Soon)

What is the Process of Hibernation?

As mentioned earlier, the process of hibernation is a physiological state where an animal’s body becomes inactive by suspending various internal involuntary actions such as heart rate, breathing rate, and metabolism. Most of the organs and tissues remain inactive and the requirement of energy reduces to a minimum. The oxygen intake reduces to almost 10% and the body temperature reduces considerably. This is the reason why animals start accumulating energy deposits and trim down their metabolic and physiological activities to trim down energy requirements. This process is what you will find common among all hibernating animals in nature.  

Which Animals Undergo Hibernation?

Only those animals that live in a harsh climate undergo hibernation or aestivation. The animals that hibernate are listed below.

• Bumblebees

There is a single queen in the entire hive and she needs to be protected from any threat. Now that we know what is hibernation, we can easily state that the queen does the same during the winter months whereas the worker bees die outside.

• Squirrel

Squirrels also do the same and escape the harsh winters by sleeping off these months entirely. Almost all species living in harshly cold climates perform winter hibernation.

• Bats

This is something out of the box. Bats can resume their hibernation after a small stint of searching or hunting for food. After the winter is over, they regain their normal physiological activities.

• Turtles

Some types of hibernating turtles live in colder places where winter is harsh.  Those who are living in a hot climate don’t hibernate but might aestivate. In fact, turtles living in hotter climates aestivate to get rid of the extreme heat and regain their physiological activities when rainfall or winter arrives.

• Snakes

Snakes escape winters by hibernating. This activity has a specific term called brumation. This term is used to classify hibernation in reptiles. 

These are a few examples of animals that hibernate. Let us proceed to the process of aestivation.

Which Animals Perform Aestivation?

As described earlier, it is a stage of dormancy where animals suspend their metabolic activities and go to a hibernating stage to avoid extreme heat and droughts is called aestivation. The best examples of the aestivation are listed below.

• Mollusca

Snails often aestivate to avoid extreme heat and drought during the summer season. Some move to the shaded regions to preserve water.

• Arthropods

Lady beetles and mosquitoes aestivate during the summer season and survive the extremely dry conditions. They regain their physiological activities once the rainy season appears. Australian crabs aestivate due to lack of food during the summer season.

• Reptiles

Desert tortoises and crocodiles aestivate in the North American deserts.

• Amphibians

Greater siren and cane toads aestivate to avoid hot climates. They move underground into someplace cooler and preserve their body energy.

Difference between Hibernation and Aestivation

Hibernation is commonly called winter sleep whereas aestivation is summer sleep. The former takes place longer than the latter. In fact, a winter sleep is conducted in a warmer place than the freezing external environments. The aestivation, summer sleep, on the other hand, takes place under the shade of trees or underground where the temperature drops significantly.

Hibernation protects an animal from internal organ damage due to plummeting temperatures. On the contrary, aestivation protects an animal from loss of water and organ damage at the same time.

A hibernation period is witnessed in warm and cold-blooded animals. Aestivation is witnessed in only cold-blooded animals.

This is all you need to know about hibernation and aestivation. The differences between these two exceptional physiological activities performed by hybernating and aestivating animals are important to note as these two processes are not the same. More examples of hibernating animals will help you in understanding the concept and learning how this process can save an animal’s life from harsh climatic conditions.