Do zoo stars like lions, pandas and brown bears hibernate?

At the zoo you can often see the mighty lion, the adorable panda and the clumsy brown bear. So do these three zoo stars hibernate? According to staff at Changsha Zoo, lions definitely do not hibernate. Because they are mammals! A mammal's body temperature is constant! It is not affected by changes in the outside temperature, so there is no need to hibernate! What is more, lions live on the tropical savanna, where winter temperatures do not drop below 15 degrees, so it simply never gets cold enough for them to need to hibernate. Pandas do not hibernate either. The giant panda has a character that fears no severe cold and never hibernates, because it is a warrior that came through the Quaternary glaciations; even when the temperature falls to minus 4°C-14°C, it still moves through snow-covered bamboo forests, choosing tasty bamboo to eat, and unlike many animals such as the black bear, it does not hide in tree holes or rock caves to hibernate. It is also not afraid of dampness, spending the whole year in gloomy, damp forests with humidity above 80%. The brown bear has the habit of hibernating, starting from the end of October or the beginning of November and continuing until March-April of the following year. In order to accumulate about 50 kg of fat needed during hibernation, in autumn it must eat 400-600 kg of berries and other food. As winter approaches, it begins to prepare a den, choosing sunny spots with fallen trees and dead branches everywhere and weaker cold winds, mostly living in large tree holes or cracks in rocks, and sometimes digging a burrow on a dry mound in a swamp. It uses its front paws to line the den with dry grass, leaves or moss. Generally each individual lives alone in one den, and only a female and her cubs under 3 years old live together. Before entering the den, it first circles the entrance for a while, then jumps in, or backs into the den, or messes up its own tracks, so as to keep enemies from finding the den and to hide itself better. During hibernation it mainly relies on the fat stored in its body to sustain life, and if there is danger, it will wake up at any time. On warmer days, it sometimes comes outside the den to move about for a while.

Appendix: Why do animals hibernate?

Hibernation, also called “winter dormancy”. In some animals, life activities are at an extremely reduced state in winter; it is an adaptation by animals to adverse external environmental conditions in winter (such as lack of food and cold). Bats, hedgehogs, Arctic ground squirrels and others all have the habit of hibernating. Hibernation is when some heterothermic animals (some hibernating mammals and birds) and poikilothermic animals can lower their body temperature in the cold winter to close to the ambient temperature (almost to 0°C), with the whole body in a numb state; when the ambient temperature further drops or rises to a certain level, or under other stimulation, their body temperature can quickly return to normal levels.

Hibernation is a “magic weapon” by which poikilothermic animals avoid food scarcity in the cold winter. When winter comes, the hedgehog shrinks into a mud hole, curls up its body, eats nothing and does not move, and it hardly breathes, with its heartbeat also astonishingly slow, beating only 10-20 times per minute. If you put it in water, it will not die even after half an hour, but when an awake hedgehog is soaked in water for 2-3 minutes, it will drown. Why is this?

During hibernation, the animal's nerves have already entered a numb state. Someone once conducted an experiment with bees: when the temperature was 7-9°C, the bee's wings and legs stopped moving, but when it was gently touched, its wings and legs could still tremble slightly; when the temperature dropped to 4-6°C, touching it again produced no reaction at all, clearly showing that it had entered a deep numb state; when the temperature dropped to 0.5°C, it entered an even deeper state of sleep. It can thus be seen that during hibernation the depth of nerve numbness is closely related to temperature.

In addition, during hibernation, an animal's body temperature drops markedly. According to research, a ground squirrel released a total of 70 calories during 130 days and nights of hibernation, but in the 13.7 days and nights after hibernation it could release 579 calories. Generally speaking, during hibernation an animal can release only 0.5 calories per day and night, but after it wakes up, when excited, it can release 42 calories per day and night. It can thus be seen that when a hibernating animal's body temperature drops, the metabolic processes in its body become very slow, so it can only sustain its life.