This is how many animals survive cold winters

the essentials in brief

• Hibernation is the winter rest phase during which life functions such as body temperature, respiratory rate and metabolism decrease
• no sleep in the true sense of the word, as the sensory organs and brain do not go into sleep mode, but remain active
• no continuous sleep phases, hibernating animals wake up every now and then
• however, you should not wake up too often, as this drains your limited fat reserves
• Differentiation between hibernation, hibernation and winter rigor

What is hibernation?

According to the scientific definition, hibernation is not a sleep - the Animals do not sleep because the rest modes for the brain and body that are typical for this phase miss. Paradoxically, some animals even have a sleep deficit after hibernating, precisely because the brain is not resting. Instead, it is a time-limited phase of life in which all vital functions are greatly reduced - the hibernating animal is basically closer to death than to life.

Why do some animals hibernate?

Since there is not enough to eat in winter, many animals shut down their body functions in winter

Hibernation is a strategy for both plants and animals to survive the winter months with little light and food. For many animals - such as insects and thus also for insect-hunting bats or dormice, who mostly eat buds and fruit - winter means a time without or with little food.

You do not create or are not able to do this, which is why they consume more energy than without shutting down their body functions they can take in - the reserves eroded over summer and autumn would be within a short time used up. The hibernation prevents the animals from starving and ensures that they live longer.

Procedure and characteristics

Scientists refer to hibernation as hibernation. The phenomenon is being intensively researched, among other things for the reason that a fallow “hibernation gene” has also been discovered in humans. This could prove useful in future space travel, such as a trip to Mars. However, not all questions regarding hibernation have been answered to this day.

How do animals know when to hibernate?

Animals know when it is time to retreat for hibernation

This also includes the question of how the animals actually know when to go into hibernation. What is certain is that it is not the incipient lack of food and the cooler temperatures in autumn that promote the readiness to sleep, but rather the increasingly shorter days. The length of the day influences the appetite and thus the creation of fat deposits. In addition, there is a hormonal change that gradually lowers the body temperature and breathing rate - the animal gradually slips into hibernation.

That happens during hibernation

Since energy has to be saved during hibernation, hibernators reduce all vital and energy-sapping functions to a minimum. This affects such elementary body functions as

• Move
• temperature
• Heartbeat
• breathing
• metabolism

Hibernating animals appear dead and in fact it is often difficult to distinguish between them: they are motionless, rigid, your breathing and heartbeat are drastically lowered and only pedal a few times per Minute on. How extreme these changes are is illustrated by the following figures using the example of the marmot:

• Body temperature: drops from 39 ° C to only seven to nine degrees Celsius
• Heartbeat: decreases from around 100 Blows per minute to just two or three
• Breaths: only one or two breaths per minute instead of 50

Hibernating bats have extremely long pauses in breathing: up to 90 minutes can pass between two breaths.

This is how animals ensure their survival during hibernation

During hibernation, the animals lose up to 50% of their body weight

Since the metabolism is severely reduced in winter, but does not come to a complete standstill, the hibernating animal must have a thick layer of fat over the summer and autumn months eat up. It then feeds on this during the hibernation phase, in which they lose between 30 and 50 percent of their body weight.

This layer of fat also serves to raise the body temperature if necessary - for example if it sinks to life-threatening depths and the hibernating animal threatens to freeze to death. Never disturb animals in hibernation, as sense organs and vital organs are still in this state work - and the animal, once woken up prematurely from hibernation, cannot find enough food and must starve to death.

Duration of hibernation

First of all: Hardly any animal hibernates continuously from autumn to spring; instead, rest phases alternate with short waking phases. The sleep periods of real hibernators last for several days to weeks, in between the animals wake up, give off faeces or urine or sometimes even change the sleeping place.

However, the duration of these phases and the length of hibernation differ between the different species - as well as according to the region in which they live. For example, brown bears that live in the far north sleep up to seven months a year without waking up. In contrast, in Central Europe with a milder climate, brown mothers give birth to their young in January - and in warmer locations or regions. In zoos with heated bear enclosures and year-round food supply, there is even no hibernation at all.

In Germany the hibernating species spend these months in hibernation:

• Hedgehog: usually between November and April
• Dormouse: September to May with sleep phases between 20 and 29 days
• Marmots: sleep up to six months a year in groups of up to 20 animals
• European hamster: sleep between September / October to April, quite short sleep phases, between which the animals wake up and eat from their supplies.
• Dormice: sleep between October and April

Who hibernates the longest?

Marmots and dormice spend the longest time in hibernation - both species sleep around six to seven months a year. The hedgehog, on the other hand, “only” lasts three to four months. Incidentally, the dormouse got its German name from its long hibernation.

Waking up from hibernation

When it is time to wake up, the animals probably have in their blood

The mechanisms that lead to waking up from hibernation in spring are just as puzzling as those that encourage falling asleep in autumn. Rising ambient temperatures may be one of the relevant causes. If it gradually becomes warmer outside, the body eventually releases hormones as well. These in turn ensure a slow rise in body temperature via the fatty tissue - because waking up from hibernation primarily means warming up.

When the core body temperature has finally reached at least 15 degrees Celsius, muscle tremors are added as a further measure to increase the temperature. The body is not heated evenly, instead the focus is on the head and torso. This is where the vital organs are located, the functionality of which must first be restored. The abdomen and extremities warm up last. In many species, this process only takes a few hours - hedgehogs, for example, warm up to a core body temperature of more than 30 degrees Celsius in less than a day.

Digression

Hiding places in the garden

What is the difference between hibernation, hibernation and winter rigor?

Scientists differentiate between hibernation, hibernation and Numbness. These three forms all denote a phase of winter calm - but with different characteristics and effects:

• Hibernation: is typical for mammals, characterized by a decrease in body temperature, respiratory rate and metabolism
• Hibernation: Body temperature remains unchanged, sleep phases are interrupted by numerous waking phases in which the animals also eat, likewise only in mammals
• Numbness: also referred to as cold rigor, typical for cold-blooded animals such as reptiles, amphibians as well as for snails and insects, here too the body temperature drops - they corresponds to the outside temperature, movements and food intake are not possible, and automatic rewarming of the body when the outside temperature is too low is not possible possible

In addition, plants are also referred to as hibernation.

Which animals hibernate in Germany - a list

This table clearly lists which animals hibernate properly, which ones fall frozen and which just rest in winter.

Who winters where in the garden?

In order to offer hibernating hibernation areas to various wild animals, you can design the garden accordingly. Hedges, meadows and a garden pond not only serve as winter quarters, but also enable winter sleepers to eat a layer of fat. In this list we have summarized for you where which animals hide in winter:

• Compost heap: Common toad
• Piles of leaves and brushwood, piles of dead wood: Hedgehogs and insects
• Tree stumps: Insects
• Piles of stones and dry stone walls: Insects, reptiles, amphibians
• floor: Insects (solitary bees, ants), amphibians, some mammals (dormice)
• garden pond: Amphibians (frogs), dragonflies (on plant stems)

Birds, on the other hand, do not hibernate, but they also need food during the cold season. In addition to a bird feeder, you provide the animals with fruit-bearing trees and bushes (e. B. Wild apples and ornamental apples, Cornelian cherry, Honeysuckle, Rowanberry, sloe etc.).

Digression

Plants in hibernation

frequently asked Questions

Are there also birds that hibernate?

No, there is no species of bird that hibernates. Instead, many birds move to warmer climes in autumn, although these do not necessarily have to be in the "south". These species do not return until spring. Others, on the other hand, such as titmice, nuthatch or crows, stay here over the winter months, but remain alert and agile.

Do insects hibernate too? What types do this and how?

Butterflies remain frozen in winter

Some insects, such as the painted lady, like birds, move over the winter to where it is warm. Many other species - butterflies as well as beetles, bees, Bumblebees, Wasps, dragonflies and ants - actually fall into hibernation, although this is somewhat different from that of mammals. In the case of the bumblebees, for example, only the young queens overwinter, and the queens get a new one the following year Establish a court, with other species only eggs, larvae and pupae survive the cold Season.

By the way: If you find seemingly lifeless ladybugs in the apartment in winter, they are not dead. You are in hibernation and should definitely be left alone.

Do my turtles need hibernation too?

Strictly speaking, turtles do not hibernate, but rather fall into a frozen state. Depending on the type and origin of the animals, this must last at least eight weeks or take up to five months. Healthy animals go into freezing conditions all by themselves, with tortoises usually burrowing. They gradually wake up again from the beginning of March.

Is it true that turtles can be hibernated in the refrigerator?

In fact, you can keep your tortoise in one - separate! - Winterize the refrigerator. What sounds strange has advantages for the animals: Here the temperature is always a constant four to four six degrees, which are ideal for wintering, and the rigid winter turtles are safe from enemies protected. It is best to pack the animal in a sufficiently large box filled with soil, moss and beech leaves, which you then place in the lower area of ​​the refrigerator.

I found a hedgehog. How do I know if he's hibernating or dead?

At first glance, it is not possible to distinguish a dead hedgehog from a hibernating hedgehog. A hedgehog in hibernation has a body temperature of only around five degrees Celsius, and it only breathes three to four times per minute. However, you can distinguish dead hedgehogs by these marks:

• hibernating hedgehogs are completely curled up, nose and feet cannot be seen
• in the case of dead hedgehogs, however, you can see the soft parts of the body
• Carefully stroke the spines: If these then straighten up again, the hedgehog just sleeps
• in dead hedgehogs the spines stay down
• The smell of putrefaction indicates a dead animal