Animals have several mechanisms that allow their survival under unfavorable conditions. One of these mechanisms is the hibernation, a form of protection against the cold and the limited availability of food.
THE hibernation is a process characterized by the reduction of metabolic activities and the establishment of a lethargic state. During hibernation, the animals are as if they were inactive, immersed in a deep sleep and with reduced heart rate, as well as the temperature, which is around 5ºC.
Hibernation is most often performed by small mammals such as hamsters, squirrels and bats. despite the bears are always pointed out as hibernating animals, many authors do not consider this statement correct. The body temperature of bears drops relatively little, unlike other animals that, during hibernation, have their temperatures close to the value of the environment.
The phenomenon of hibernation occurs more frequently in cold regions of the planet, where the winters are extremely strict. With the arrival of this season, in addition to the sharp drop in temperature, there is a reduction in the amount of food, which represents a threat to the survival of several species.
Faced with the risks of winter, the animals are starting to prepare themselves to face this season. During the phase known as pre-hibernation, hibernating animals begin to feed in order to store lipids. These accumulated lipids will serve as a reserve and will be used during the period of inactivity.
After pre-hibernation, the hibernation itself. At this stage, the accumulated fat is used to generate energy for the body and there is a marked reduction in metabolism, temperature, breathing and heart rate. With the reduction of activities, hibernating animals are able to achieve great energy savings.
In spring, hibernating animals come out of deep sleep and resume their metabolic activities. To be able to return to a normal state, animals obtain energy through the oxidation of brown fat.
It is concluded, therefore, that hibernation is an important example of the capacity that living beings have to change the functioning of their bodies to survive in situations of extreme stress. Without this ability, it is likely that many species would not have established themselves in inhospitable environments.
By Ma. Vanessa dos Santos