When is hibernation?

Hibernation is also called "winter sting". Some animals are in a state of extremely reduced life activities in winter, which is a hibernating frog for animals facing unfavorable external environmental conditions (such as lack of food and cold) in winter.

An adaptation. Bats, hedgehogs and polar squirrels all have hibernation habits. Hibernation means that in some warm-blooded animals (mammals and birds), in the cold winter, the body temperature can be reduced to close to the ambient temperature (almost to 0℃), and the whole body is paralyzed. When the ambient temperature further decreases or increases to a certain extent, or under other stimuli, the body temperature can quickly return to normal level. Hibernation is a "magic weapon" for warm-blooded animals to avoid the cold winter when food is scarce. You see, when winter comes, the hedgehog will shrink into the mud hole, curl up into a ball, eat nothing, hardly breathe, and its heartbeat is surprisingly slow, jumping only 10 ~ 20 times per minute. If you soak in water, you won't die for half an hour, but a sober hedgehog will drown if you soak in water for 2 ~ 3 minutes. Why? When hibernating, the animal's nerves have entered a state of paralysis. Someone once experimented with bees. When the temperature is 7 ~ 9℃, the wings and feet of bees stop moving, but they can still shake slightly when touched lightly. When the temperature drops to 4 ~ 6℃, touch it again and it doesn't respond at all. Obviously, it has entered a state of deep paralysis. When the temperature drops to 0.5℃, it goes into a deeper sleep state. It can be seen that the depth of nerve paralysis during hibernation is closely related to temperature. In addition, when hibernating, the body temperature of animals drops obviously. According to the research, during 130 days and nights of hibernation, the Citellus dauricus * * releases 70 calories, but after hibernation, it can release 579 calories during 13.7 days and nights. Generally speaking, an animal can only release 0.5 calories every day and night during hibernation, but when it wakes up excited, it can release 42 calories every day and night. It can be seen that when the body temperature of hibernating animals drops, the metabolism in the body becomes very slow and can only maintain life. Animal subcutaneous fat, on the one hand, can maintain body temperature, and more importantly, it can supply internal friction during hibernation. The average weight of animals before hibernation is 1 ~ 2 times that of normal animals, and the weight gradually decreases after hibernation. For example, woodchucks that hibernate 163 days lose 35% weight; Bats can lose 33.5% weight by hibernating 162 days. Hibernating animal

When animals hibernate, blood cells will be greatly reduced. Usually, there are 1 2180 white blood cells in the blood of1cubic millimeter woodchucks, but there are only 5950 white blood cells on average during hibernation. Strangely, however, although the white blood cells of the "guards" in the body are greatly reduced, the hibernating animals have never been found to be sick. So why do animals go into hibernation at some time every year? Some kinds of mammals, such as monotremes, marsupials, insectivores, Chiroptera, rodents and primates, and some birds, such as brown swift and hummingbird, hibernate, so they are called hibernating animals. This animal is small in size and has a high metabolic rate. Compared with large warm-blooded animals, it consumes relatively more energy to maintain a constant body temperature. Animals such as bears and skunks will be paralyzed in winter, but their body temperature will not drop or drop a little, so they are called semi-hibernating animals. Thermotropic animals will be paralyzed in winter, but their body temperature will change passively with the ambient temperature. When the temperature drops below the tolerable temperature, they will not be awakened, but will freeze to death. This behavior is completely different from hibernation of warm-blooded animals. Call it dormant sleep. The annual cycle of hibernating animals can be divided into non-hibernating season (breeding season) and hibernating season. Hedgehogs in Beijing go to bed at the end of March and breed immediately. After finishing breeding, they turn to fattening period, which is a non-hibernating season until 10. 65438+1October-March is the hibernation season. At this time, animals crouch, do not eat or drink, and the metabolic rate is minimized. In these two seasons, the physiological state of animals is very different, but they are interdependent. Fattening in the late non-hibernation season stores energy for hibernation. In the late hibernation season, gonads begin to develop, and animals can reproduce immediately after sleeping. The body temperature of hibernating animals is constant in non-hibernating season, but it changes in hibernating season. So they are called animals with different temperatures. In the non-hibernating season, its body temperature fluctuates between 2℃ and 5℃, while the temperature fluctuation of non-hibernating animals close to it is only about 0.5℃. In addition, hibernating animals have great tolerance to low temperature. The lethal hypothermia of humans is 29 ~ 26℃, and that of rats is 15 ~ 13℃, while hibernating animals can tolerate the low temperature close to 0℃ or even ultra-cold state. For example, bats can recover from freezing to -9℃, and their body temperature will rise to normal through automatic heat production. This is an important feature that distinguishes warm-blooded animals from warm-blooded animals or warm-blooded animals.

Discrimination of the concept of editing this paragraph

Animals hibernate when they stop living. Generally, it refers to the seasonal inactivity of warm-blooded animals, but it is also suitable for the wintering of terrestrial animals (arthropods, terrestrial shellfish, amphibians, reptiles, etc.). ) in a broad sense. Rats hibernating at variable temperature

With the coming of winter, the body temperature of things drops with the outside temperature, so that it soon becomes impossible to carry out life activities. But before that, it moved to a place where the wind and temperature did not drop sharply and entered hibernation. Generally, choose the underground of sunny slope or under the stone. As a preparation for hibernation, animals accumulate fat in their bodies. For insects, eggs, larvae, pupae and adults can be selected to overwinter at a certain stage according to different species. The hibernating animals in warm-blooded animals are small mammals, such as stingers, squirrels, bobcats and bats. Compared with large animals, they have a large ratio of body surface area to volume, so they release a large proportion of heat, and they lack the productive food needed to maintain their body temperature in winter. So hibernation is an adaptation to these conditions. Cold, lack of food and water, shortening of the day and other stimuli act on the pituitary-endocrine system of the brain, inducing hibernation, but its mechanism is still unclear. In order to prepare for hibernation, the body synthesizes a lot of fat, or stores food in the nest. The unsaturation of tissue fat increases and the melting point decreases. The body temperature drops slowly, forming a state that is only 0.5-2.0℃ higher than the outside temperature. The number of heartbeats, breaths and metabolism are only a few tenths of the normal state. Blood sugar also decreased, and Mg2 in serum increased. Compared with non-hibernating animals and hibernating animals, their tissues have strong cold resistance, especially the function of cell membrane can remain normal at extremely low temperature. During hibernation, the thermoregulation function is not completely lost. When the body temperature reaches a certain limit, the thermoregulation function works, and some people start to wake up. Many kinds of animals can wake up regularly to excrete and eat during hibernation. Compared with going into hibernation, the body temperature changes (rises) faster when you wake up. Under the control of the sympathetic nervous system, the brown adipose tissue of the neck and scapula is activated, generating a lot of heat. This heat spreads to all parts of the body with the blood. Meat-eating bears and skunks stay in caves in winter, but they are in a state of near sleep, and their body temperature drops only a few degrees, and they can respond immediately to external stimuli.

Edit this paragraph classification stage

Hibernation can be divided into three stages: entering sleep, deep sleep and leaving sleep. It takes about one to several days for the body temperature of sleeping animals to begin to drop to a stable temperature close to the ambient temperature.

fall asleep

The external stimulus of sleep is mainly temperature. The upper limit of the ambient temperature for various animals to sleep varies greatly: snakes hibernate in bats.

Bat 24 ~ 28℃, hedgehog 27℃, squirrel 20 ~ 22℃, hamster 9 ~ 10℃. The supply of light, food and drinking water also affects sleep. The internal factor of falling asleep is mainly weight. It is generally believed that when animals gain weight rapidly, they have internal conditions for sleeping until they remain at a relatively high level. Otherwise, although the ambient temperature is low, animals will not sleep. After the body temperature is set close to the ambient temperature, you will go into a deep sleep.

deep sleep

The length of this stage is uncertain and usually lasts for several months. At this time, the physiological state has changed a lot. Breathing is obviously reduced, such as hedgehog's breathing movement, from 6 ~ 18 times per minute at room temperature to 1 ~ 3 times per minute (28 ~ 18℃). At this stage, intermittent (paroxysmal) breathing sometimes occurs, that is, there is a long pause after a short rapid continuous breathing. Unlike warm-blooded animals, intermittent breathing in hibernating animals is a normal physiological state. At the same time, the circulatory system has also undergone obvious changes, and the heart rate has slowed down extremely. The heart rate of hibernating bats dropped from 330 ~ 920 beats per minute to 30 beats per minute, hummingbirds dropped from 480 ~ 1200 beats per minute to 48 beats per minute, and ground squirrels dropped from 300 beats per minute to 4 ~ 7 beats per minute. At the same time, blood pressure is extremely low The blood pressure of hamsters and marmots decreased from 100 mm Hg at room temperature to 50 mm Hg, and that of hedgehogs decreased from 1 13 mm Hg to 35 mm Hg. At this time, the peripheral blood vessels are widely contracted, and only the most important chest organs and brain maintain a low level of blood circulation. This can save energy to the maximum extent and ensure the continuation of life activities. When the ambient temperature rises to a certain height, the sleeping animals will wake up quickly, their body temperature will rise, and the functions of various systems will return to normal (out of sleep).

couldn't fall asleep

The sleeping temperature of hedgehog is about 6 ~ 9℃ (2 ~ 65438 05℃), and that of weasel is about 65438 00℃. In addition to this spontaneous awakening, other external factors, such as electricity, machinery, cold or heat, chemical stimulation and injection of drugs or hormones, can awaken hibernating animals. At the beginning of awakening, breathing changes from rhythmic to intermittent. After several paroxysmal breaths, it becomes rhythmic breathing, and the frequency is getting faster and faster. For example, hedgehogs can reach 60 times per minute, and then wake up and tend to be calm, becoming 36 ~ 40 times per minute. The heart rate also gradually accelerated to above normal level, and then returned to calm. This hyperactivity of breathing and heart rate is related to trembling and heat production at the beginning of awakening. At the same time, the blood vessels in the front of the body relax and strengthen the blood circulation of the heart, lungs and brain. After the front part of the body is rewarming, the blood vessels in the back part of the body begin to relax and rewarming quickly. Because of this active rewarming, the whole process only takes 1.5 ~ 2.5 hours, and the body temperature can be raised by more than 30 degrees, and it is completely awake. During hibernation, animals are in a hibernating array state of alternating activity (normal temperature) and paralysis (low temperature). The activity lasts about 8 hours to 2 days. Some kinds of animals excrete or eat during this period. Most kinds of animals do not eat, but regulate some physiological balance. Hibernating animals don't eat or drink during the hibernation season of 100 days, because they have sufficient energy reserves and their metabolism is minimized, which is 1 ~ 2% of that of active animals. Its respiratory quotient is close to 0.7, and it mainly relies on oxidized fat to supply energy and water. Hibernating animals store 30 ~ 50% of their body weight during the fattening period, and most of them are concentrated under the skin, which not only provides energy but also keeps warm. The brown fat of hibernating animals is more than that of non-hibernating animals, and it decreases the most after hibernation. Endocrine glands once thought to be related to hibernation are called hibernation glands. It is closely related to the awakening of hibernating animals.

Edit the inducing factors in this paragraph.

The inducing factors of hibernation are some external factors, such as the drop of environmental temperature and the shortage of food in autumn. But some experts say that hibernating squirrels.

It is believed that the gradual shortening of the day is a hibernation signal, which will lead to changes in some internal factors, such as changes in hormone levels and the regulation of seasonal biological clocks. The biological clock seems to affect animal behavior, such as fat storage and preparation for hibernation. There is also the anesthetic effect of high concentration of carbon dioxide in hibernating places, which may also be the inducing factor of hibernation. The increase of ambient temperature and the accumulation of metabolites may be awakening signals. When hibernating animals wake up, their body temperature will rise slowly. Hormones can cause brown adipose tissue to decompose, providing energy for the initial increase of body temperature. When the body temperature reaches 15 degrees Celsius, the muscles will start to tremble, further warming the body. In the chest and head with important organs, the temperature will recover faster than other parts of the body. The duration of hibernation varies from animal to animal. European hedgehogs are 3 to 4 months old. Hibernating mice can sleep for six to seven months. But we can't simply think that hibernation is a continuous process for several months. On the contrary, the more common hibernation is intermittent, with a long rest state and a short awakening state inserted in low metabolism. However, animals can't always wake up, because they need to consume energy every time they wake up. Too many times of waking up will lead to premature exhaustion of fat storage, so that when they really wake up next spring, there will be no "fat" available. Animal hibernation is most affected by natural conditions. The more external stimuli, the stronger the adaptability of internal instinct. First of all, the external temperature has an important influence on animal hibernation. When the ambient temperature is between 5℃ and 10℃, it is most suitable to cause hibernation. Secondly, the lack of food is a factor leading to hibernation. For birds, as long as food is restricted or hungry, they will immediately go into a lethargic state. Thirdly, light is also an important external condition that leads to hibernation. If the light time is reduced or dimmed, animals will soon start to hibernate.

Edit this paragraph adjustment mechanism

From the above-mentioned regulating activities of respiration, circulation and body temperature, it can be seen that the center keeps active activities. The central activity of Citellus dauricus was studied by autoradiography. It is found that the nuclei of its central activities are different in different stages such as falling asleep, deep sleep and awakening, which shows that different stages of hibernation are regulated by different centers. No special central nucleus regulating hibernation has been found. The study of EEG shows that only 10% neurons may be active during hibernation, and the EEG of hibernation and sleep is quite similar, so it can be considered that hibernation may belong to the thermoregulatory expansion of slow-wave sleep. The preoptic area-the anterior hypothalamus (PO/AH) which controls thermoregulation also plays a regulatory role during hibernation. High hibernating hibernating fish

The temperature in PO/AH region of animals can reduce metabolic heat production and rectal temperature. On the contrary, lowering the temperature in this area will increase heat production, leading to an increase in rectal temperature. This reaction is consistent with that of non-hibernating animals. However, animals in deep hibernation do not have this reaction. If the temperature of PO/AH drops below 65438 0℃, this reaction will resume and cause awakening. When the animal is awake and its body temperature rises, PO/AH is heated and the animal will return to deep sleep. This shows that the hypothermia of hibernating animals is not a failure of temperature regulation, but an adaptive active expansion. Hibernating animals monitor the change of external critical temperature by an alarm temperature sensor. It is known that the weasel's early warning temperature sensor is inside the central nervous system, while the hibernating Dormouse is on its hind legs. It is believed that the process of hibernation is regulated by many endocrine glands, but the results obtained by different experimental animals or different methods are inconsistent or even contradictory. Therefore, progress in this regard is very slow. There are many reports on the relationship between pineal gland and thyroid gland and hibernation, and it is certain that hibernation requires pineal gland. When hibernating, the thyroid gland drops, and even during the fattening period, the secretion begins to decrease, which is beneficial to the accumulation of fat. Serotonin is also involved in the sleep process of some animals. Some scholars have found the trigger and inhibitor of hibernation in the blood of hibernating animals. Injecting the trigger into living animals can induce thirteen squirrels to fall asleep in non-hibernation season, and adding inhibitors can prevent the trigger from working. But this discovery needs further confirmation.

Edit this hibernating animal.

An animal on earth that can control its body temperature is called a warm-blooded animal. Animals whose body temperature can be regulated by the change of environmental temperature are called thermogenic animals. When winter is cold, their body temperature drops and their activities stop. At this time, their energy consumption is also reduced, so they can maintain their lives without eating food. There are three types of hibernation. The first is the hibernation of amphibians and reptiles such as snakes and frogs, whose body temperature is in harmony with the surrounding environment. If the ambient temperature drops and the body temperature drops, it will go into hibernation and cannot be adjusted. The second kind of animals, such as squirrels, usually keep their body temperature constant. During hibernation, they can lower their body temperature to the temperature close to the surrounding environment, but in order to avoid freezing body fluids below 0℃, their body temperature is maintained at 5℃. The third kind is a bear. When a bear hibernates, its body temperature drops by only a few degrees, but it can sleep without food for a long time, which should be close to between sleep and hibernation under strict classification. Is there a difference in body structure between hibernating mammals and humans? The answer is no, there is no difference between them in organs and tissues, but hibernating mammals can use special factors to control the metabolic state of neurohormone system to regulate organs. If the genetic factors of this control can be found, it is not impossible for humans or other animals to hibernate in the future. In Taiwan Province Province, because of the warm weather, the hibernating time of animals should be very short, especially the hibernating animals in zoos, which can still move freely in winter under the facilities of heat preservation and cold protection. Hibernating mammals, rodents, chinchillas, European Dormouse, golden hamster, Chiroptera bat, hedgehog in insectivora, frog and snake can't find scorpions.

Edit this hibernation behavior.

In autumn, hibernating animals have the opportunity to find hibernating places: hollow trunks and caves, which are covered with grass, straw, leaves and hair as cushions. In such a well-arranged shelter, they will curl up in groups of three or five, drooping their eyelids and spend the winter in this low-energy form-torpor (Latin: boring). Their body temperature will drop to 1 to 9℃. All physical functions will be greatly reduced. Breathing is very weak, the heartbeat is slow, and the sensitivity to external stimuli is reduced. If you photograph a hibernating bat with an infrared camera, you will see that the bat's body is dark blue. For example, when a groundhog hibernates, its body temperature will drop from 39℃ to 7℃. Heart rate dropped from 100 to 2 or 3 beats per minute. The breathing frequency can be extended to once every hour. Metabolites of the intestine and liver will be collected in the lower part of the intestine and excreted after waking up. Animals stop eating when they hibernate, or eat when they are awake for a short time. Hibernating animals live on their own fat, especially the brown adipose tissue (IBAT) between the shoulder blades. This tissue is located in the shoulder and neck, and it is a very important energy source, especially when the outside temperature rises and animals wake up from hibernation for several hours. In the second half of the awakening process, animals can raise their body temperature to a normal level by shaking their bodies (flexors and extensors contract at the same time, a high-energy action). The higher the temperature, the faster the animals breathe.

The length of hibernation

The duration of hibernation varies from animal to animal. European hedgehogs are 3 to 4 months old. Hibernating mice can sleep for six to seven months. But we can't simply think that hibernation is a continuous process for several months. On the contrary, the more common hibernation is intermittent, with a long rest state and a short awakening state inserted in low metabolism. However, animals can't always wake up, because they need to consume energy every time they wake up. Too many times of waking up will lead to premature exhaustion of fat storage, so that when they really wake up next spring, there will be no "fat" available.

The awakening of spring

The reason for awakening in spring is still unclear. The increase of ambient temperature and the accumulation of metabolites may be awakening signals. When hibernating animals wake up, their body temperature will rise slowly. Hormones can cause brown adipose tissue to decompose, providing energy for the initial increase of body temperature. When the body temperature reaches 15℃, the muscles will start to tremble, further warming the body. In the chest and head with important organs, the temperature will recover faster than other parts of the body.

Negative Effects of Hibernation on Memory

The University of Vienna found in the study of European Citellus dauricus that hibernating for several months will have a negative impact on the memory of hibernating animals. Compared with animals that don't hibernate, European ground squirrels can't solve the tasks they learned before hibernation, such as finding the right route in the maze or controlling the lever of food machines. One possible explanation is that hibernation reduces nerve activity. Scientists have even proved that neuronal connections in the brain will be disconnected during hibernation.

Discrimination of the concept of editing this paragraph

winter vacation

The winter rest of brown bears in their nests (German: Winterruhe) is different from hibernation. During the winter break, the body temperature of brown bears will not drop as much as that of real hibernating animals. This winter break without large-scale cooling can also be seen in badgers, squirrels and raccoons. During this winter break, these animals often wake up and change their sleeping posture. Brown bears will spend seven months in their nests, half asleep and half awake, eating, drinking and defecating, and living on their own fat. American scientists have found that this semi-sleep state is caused by a hormone called Hibernation-induced HIT. These substances can make brown bears survive the winter without losing muscle strength. A person in a similar state, such as in a hospital bed, will lose 90% muscle strength.

Winter rest state of deer

Recently, it has been found that native deer will also drop their body temperature to 65438 05℃ in winter and enter a dormant state. By reducing the metabolic rate to the night level, deer can survive this cold season. Veterinary research at the University of Vienna found that the richness of food will affect this regulation mechanism of body temperature and metabolism. Protein's abundant food, which is not common in winter, may unnecessarily increase the metabolic rate of animals. Therefore, improper feeding in winter will lead to spring famine, because the metabolism of deer has not decreased in winter, and the consumption of forage in the forest is too large, resulting in a shortage of forage in spring. Veterinary researchers at the University of Vienna believe that the line between hibernation and winter break is no longer clear. Many animals can lower their metabolism and body temperature through similar regulation mechanisms, and seals and whales may also use the same mechanism during long-term snorkeling.

Frozen state of temperature-changing animals

Contrary to hibernation, it is a frozen state, which can be seen in many warm-blooded animals living in certain climatic regions-snails, some insects, most reptiles (snakes, turtles, lizards) and amphibians (toads, frogs). Newts will last for 3 to 4 months, slow-limbed lizards and dragon vipers will last for 4 to 5 months, and rain frogs and sand lizards will stay frozen for 5 to 6 months.

Summer sleep and dry sleep

There is also summer sleep. Crocodiles and snakes (such as the dead viper) living in tropical areas spend their summers in swamps and other places during the dry season. Burgundy snails living in temperate zones sleep in summer or dry when there is no water. There are also some frogs and toads, such as horned toad or African bullfrog (Pyxicephalus adspersus), who also sleep in summer. The physiological function of summer sleep is to save energy in hot and grain-deficient seasons; Like hibernation, these animals reduce their metabolism when they sleep in summer. The amphibians mentioned above will even reduce the intestinal capacity by 40%. This can reduce the food intake by 60%. When there is no shortage of food, the intestine will return to its original size.