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Wild animals feel the cold, just like humans do. They use various -- and often surprising -- strategies to survive the coldest temperatures. Here are some of them.
Wild animals feel the cold, just like humans do. They use various -- and often surprising -- strategies to survive the coldest temperatures. Here are some of them.
In cold weather, some animals go into hibernation for several weeks or months. This survival strategy induces major physiological changes in the animals concerned. They enter a state of deep lethargy, enabling them to avoid having to eat or drink for the duration of their hibernation.
The Arctic ground squirrel goes even further. This light brown squirrel sleeps from early October until mid-April -- more than half of the year. This process results in a slowing of its blood flow and a decrease in its body temperature, like any animal that hibernates. Except that, in the case of this particular squirrel, it goes down to - 2,9 °C, leading to the loss of certain vital connections between its neurons. However, biologists have found that the animal's brain is able to compensate for these losses by creating more neuronal links than it had before hibernation. This ability fascinates the scientific community, which is envisaging it as a potential pathway to reversing the cellular damage caused by neurodegenerative diseases such as Alzheimer's.
Winter coats and antifreeze proteins
Other animals, like the Arctic fox, survive the winter period thanks to their coats. This animal -- sometimes known as the polar fox, snow fox or white fox -- lives in regions where temperatures can drop to -70°C. Its white fur serves as a cozy blanket, as does its bushy tail behind, which it uses to protect its ears and small muzzle from the cold. The manul, or Pallas's cat, also uses its imposing tail to brave the harsh winters of the steppes and mountainous regions of Central Asia. This measures between 25 and 30 centimeters, almost half of its whole body length. It's not surprising, therefore, that the animal nestles its two front legs on its tail like a cushion to keep them warm.
Not all animals can rely on their coat when they start feeling the effects of winter. But they do have other assets to get them through the season. One such animal is the polar cod. This aquatic animal is a poikilothermic organism, like all fish. In other words, its body temperature is directly related to that of its natural environment. The polar cod generally lives in waters with temperatures varying from 0 to 4 °C, even if they can sometimes be lower. However, this fish adapts by producing antifreeze proteins. These proteins bind to the ice crystals in its blood to prevent it from freezing completely.
All for one and one for all!
There's no antifreeze proteins for emperor penguins. Yet, they have to face temperatures below -40°C and winds sometimes blowing up to 250 km/h. Their secret lies in the four layers of feathers that cover their bodies. These interlock with each other, creating a waterproof windproof structure. While their backs and bellies are very well insulated, emperor penguins lose some heat from their eyes, fins and legs. However, they have a thick layer of fat under their skin and a special blood circulation system, which allows them to maintain their body temperature despite facing extreme weather conditions.
But the real strength of emperor penguins lies in their social structure. In the depths of winter, they huddle together in what's known as the turtle formation. In other words, they crowd together, heads down, to keep warm. They constantly change places to ensure that the same penguins don't remain exposed to the cold. This strategy is very efficient since the temperature in the heart of the group can reach 34 °C, compared to - 35 °C in the surroundings. Even more impressively, emperor penguins adopt this behavior from a very young age. It can be observed in the nurseries, the groupings of chicks that form when the adult penguins head off to find food at sea.
