A curious question for the Year of the Snake! Will the lively New Year wake up hibernating snakes?

Review expert: Wang Lei, National Park and Nature Reserve Researcher, PhD in Ecology

Editor's Note

The Year of the Snake is here. How much do you know about snakes? Beijing Science Center has carefully planned a series of popular science columns titled "Curious Questions in the Year of the Snake" to explore the wonderful world of snakes from a scientific perspective and start a wonderful journey of exploring the science of snakes in the new year.

Winter is coming, the weather is cold, and snakes are going into hibernation. Why do snakes hibernate? During the Spring Festival, will the sound of firecrackers and the festive atmosphere wake up the hibernating snakes?

Image source: Xinhua News Agency

What is hibernation?

Hibernation is a way for some animals to survive in extreme environments. There are two main reasons why animals hibernate: food scarcity and cold.

Animals that hibernate due to food shortages are mainly mammals, such as bears and hedgehogs. Hedgehogs are insectivorous animals, and in temperate regions, once the end of autumn comes, insects basically disappear (overwintering in the form of pupae), and hedgehogs have no choice but to hibernate in warm firewood piles.

Although bears are carnivores, plant food accounts for more than 65% of their diet. Once winter comes, bears living in temperate or frigid zones hibernate because of the large-scale reduction of plants.

Why do snakes hibernate?

Snakes hibernate because it's cold. Snakes are cold-blooded animals, so they don't need to consume energy to maintain their body temperature. The benefit is that they consume only 30% of the calories consumed by normal warm-blooded animals.

However, snakes cannot regulate their own body temperature, and their body temperature will change with the environment. When the ambient temperature is too low, the biological enzymes in the snake's body cannot work properly, and the metabolism will also decrease, making it difficult to move. If the environment is below 0℃ for a long time, the snake will die.

In this environment, only hibernation can save them, because hibernation can effectively reduce metabolism and put them in a state of "suspended death". Even if they do not eat or drink, they can rely on the nutrients in the body to maintain life until spring comes and they can become active again.

Generally, snakes will hibernate when the temperature is continuously below 10℃. Before hibernation, they will eat frantically, not only to fill themselves up, but also to accumulate subcutaneous fat. After all, once hibernation begins, it can last from 3-4 months to half a year.

In northern my country, snakes usually hibernate from November to March or April of the following year; the hibernation period of snakes in the south is shorter.

Snakes hibernate in groups, and this collective hibernation helps maintain temperature.

Will a hibernating snake be awakened?

When hibernating, snakes usually choose places far away from the ground, such as rat holes, tree holes, and rock crevices. They are far away from human activity areas and are basically not disturbed by human activities.

It is indeed possible for hibernating snakes to be awakened, but this situation depends on many factors. First, snakes react differently to external stimuli at different stages of hibernation. In the deep sleep stage, snakes' perception ability is significantly reduced, and they can hardly perceive changes in the outside world, but if there is a strong attack or external stimulation, they may still wake up. During the hibernation period and the period of waking up, snakes' bodies are relatively flexible, and they are more likely to wake up or even fight back when facing danger. Secondly, the awakening of snakes is closely related to the ambient temperature. If the temperature outside rises, even snakes in deep sleep may wake up and leave the hibernation point to move around.

Therefore, although hibernating snakes are in a dormant state most of the time, they may still wake up due to external stimuli or changes in ambient temperature.