When animals hibernate, how low can their body temperature drop? The answer is unexpected

The cold winter has arrived, and it is time for animals to hibernate. So why do animals hibernate while humans don’t?

Hibernation is a way for animals to cope with the cold season. During this period, individual activities are reduced or stopped, and they fast for a long time. Therefore, during hibernation, animals will generally reduce their metabolism. How to reduce metabolism? One way is to reduce heart rate and other methods, and another way is to reduce body temperature, which can reduce metabolism overall. Do animals consume their own energy when hibernating?

01 Will hibernation consume one’s own energy?

Do animals consume their own energy when they hibernate? The answer is yes. As long as they are living organisms, they will inevitably consume energy, even when they are hibernating. Hibernation only slows down the metabolism, not stops it. As long as there is metabolism, energy will be consumed.

In fact, even if we freeze cells at extremely low temperatures, such as -80℃, we cannot completely stop metabolism, and they are still undergoing a weak metabolism. Some people also believe that even in the current extreme freezing of liquid nitrogen at -196℃, this process is still going on very weakly.

Therefore, energy consumption is inevitable. Of course, during hibernation, animals will generally lower their heart rate.

02 Will the body temperature drop during hibernation?

Will the body temperature of animals drop during hibernation? The body temperature will drop, but the extent of the drop depends on the situation. Because we don't have much to refer to.

It is well known that poikilothermic animals have lower body temperatures during hibernation. However, it is not so easy to say for homeothermic animals, because there are very few homeothermic animals that can hibernate. Common examples include brown bears, bats, hedgehogs, polar squirrels, etc., which are mammals.

The body temperature of brown bears will drop slightly when hibernating, and some people believe that it drops by 1-9℃.

Bats can also hibernate, and their body temperature during hibernation is between 6-30℃. However, it is worth mentioning that although bats are homeothermic animals, their body temperature fluctuates greatly.

When a hedgehog hibernates, its body temperature drops from its normal 35°C to around 7.5°C.

These are all above 0℃ to prevent body fluids from freezing. The more surprising one is the polar squirrel, which lives in the Arctic Circle as its name suggests.

When this thing hibernates, its body temperature can drop below 0℃, reaching -3℃, which is extremely rare.

That year, scientists recorded that the polar squirrel's abdominal temperature was as low as -2.9℃ through the implantation of temperature-sensitive radioactive sensors.

You know, in our common sense, water will freeze when it is below 0℃, but the core body temperature of polar squirrels can actually be below 0℃, which is simply amazing, so this research was directly published in Science that year.

Of course, not every part of the body is below 0℃. The following figure shows the body temperature of different parts of the body. It can be seen that many parts are still above 0℃.

In order to achieve this ultra-low temperature hibernation, polar squirrels can breathe as fast as once per minute, and the hibernation period is also very long, reaching 8 months.

It is worth mentioning that scientists also studied its blood, trying to find its antifreeze mechanism, but no antifreeze components were found in the blood.

To sum up, animal hibernation is a biological phenomenon, which is an adaptation of animals to adverse external environmental conditions in winter (such as food lack and cold).