Hibernation is an adaptation of certain animals to survive periods of extreme cold and especially winter. For several days to several weeks, these animals conserve their energy by plunging into a state of controlled hypothermia. Their metabolism slows down drastically, which lowers their heart rate, breathing rate and body temperature; they no longer eat, but have made large fat reserves before and limit their energy consumption as much as possible. During the times when the climate is the harshest, they thus maximize their chances of survival by remaining sheltered in a more or less deep torpor depending on the species. The primary purpose of hibernation is therefore not only to escape the cold, but to escape all the hardships of winter: food is scarce, days are short, water freezes, shelter is less because the vegetation is less dense… It is easier to avoid this period than to face it, and the two main options for animals for this are migration or hibernation.
These hibernating animals
If the brown bear (Ursus arctos) regarded by the general public as an emblematic dormancy, it is actually a semi-dormancy. His heart rate slows, but his body temperature remains fairly stable and he can be easily awakened. The same behavior, called hibernation, is seen in badgers (Meles meles) and raccoons (Procyon lotor). True hibernators include the gray dormouse (grin grin), which decreases in stiffness from October to April; this very long hibernation period gave rise to the expression “slept like a dormouse”. The arctic chipmunk (Urocitellus parryii) disappears into its cave covered with lichen and muskox hair for nearly eight months; it is one of the few arctic animals that actually hibernates. During this epic hibernation, his body temperature drops to -3°C and his heart rate drops to just one beat per minute.
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