What is hibernation?

We explain what hibernation is, what it is for and its differences with wintering, dormancy and estivation. Also, what animals hibernate.

1. What is hibernation?

Hibernation is the ability of some animals to adapt to the very low winter temperatures , through different mechanisms of internal metabolic regulation . It induces in them a state similar to hypothermia for days, weeks or even months, then recover and return to life when temperatures are more appropriate.

It is a typical mechanism of warm-blooded animals (homeotherms), although some species of cold-blooded animals (poikilotherms) have also demonstrated similar behaviors .

Generally, the animal that is about to hibernate chooses a suitable place for it, where it feels safe. Then it decreases your vital functions for sleeping during the period of greatest cold , during which it depends on the accumulated food reserves in your body during the months before winter.

Its metabolism operates slower, its breaths decrease in rhythm and the animal seems submerged in a deep coma, from which it can wake up when the time is appropriate.

Hibernation operates in a different way, depending on the species of animal, but it is part of the set of survival strategies that, in the face of the most extreme cold climates, living beings put into practice . However, the exact mechanisms of its operation are not yet perfectly known.

2. Hibernation or wintering

The terms “hibernation” and “wintering” even if they sound similar and in principle have the same task, are not the same. Both refer to particular actions that, during the winter, the animals undertake to take refuge from the cold.

On the one hand, hibernation involves isolation and surrender to a deep stupor. It requires weeks of preparation and accumulation of energy resources in the body .

On the other hand, wintering is a geographical displacement towards warmer latitudes , where animals wait for the cold to remit and thus be able to return home without suffering the rigors of winter. Some animals hibernate and others, on the other hand, winter.

3. Dormancy

Dormancy is a process similar to hibernation, in which living beings (animals and plants) respond to adverse environmental conditions by assuming a form of latency, that is, of metabolic slowness. Dormant animals suspend their growth and development processes, as well as their physical activity .

Hibernation, estivation, dipausa and brumation are considered forms of dormancy. There are two forms of dormancy, according to the relationship between the living being and the threatening environment:

• Predictive dormancy . It occurs when the living being undertakes its dormancy process before the environment becomes hostile, that is, as a forecast of the next unfavorable climate environment.
• Consequential dormancy . It occurs when the living being undertakes its dormant process as a reaction to the change of the environment, that is, once said change has already occurred.

4. Animals that hibernate

There are many animals capable of hibernating, but the best known are bears from polar and circumpolar regions , such as the brown bear ( Ursus arctos ).

They also hibernate the Pachuca chotacabras ( Phalaeonoptilus nuttalli ), some species of bats from the temperate zone ( Vespertilinidae family ), the European common hedgehog ( Erinaceus europaeus ), the wild dogs ( Sciuridae family ) and some European rodents such as the marmots.

5. Hibernation and estivation

Hibernation and aestivation are reactions to extreme weather, but completely opposite cases: Hibernation occurs at very cold climates and aestivation is made to weather very hot and dry . Stimulation is common in tropical animal species or in regions of enormous solar impact, such as deserts .

Many animals resort to burying themselves in mud to preserve their body temperature and protect themselves from drought, while others simply resort to numbness and immobility. The estivation usually lasts a few weeks or even months , but there are species of batracians in which there is a prolonged estivation of which only some individuals come back to life.