In winter it is cold and many animals can no longer find food. So that they can survive the cold season, they have developed different survival strategies. One of them is hibernation. You can find out what this is all about and who suffers from winter torpor in this article.
What happens to animals in hibernation?
Winter torpor is a survival strategy of cold-blooded animals such as insects, snails, amphibians and reptiles, in which their body temperature and vital functions such as breathing and heart rate are significantly reduced. It occurs when the ambient temperatures fall below a critical value, usually 10°C.
- Winter torpor only occurs in cold-blooded animals, i.e. H. in species whose body temperature depends on the ambient temperatures
- characteristic of insects, snails, amphibians and reptiles; Fish, on the other hand, are usually awake in winter
- Body temperature and other vital functions such as: B. Breathing and heart rate are significantly reduced
- Death-like state, waking up from hibernation is not possible (only if the ambient temperature increases)
- Frost is fatal if it lasts for a long time and the winter-hardened animals do not have frost-proof shelter
What is hibernation?
Winter torpor only occurs in cold-blooded animals, i.e. H. in species whose body temperature depends on the outside temperature. Mammals are generally uniformly warm animals and always maintain their temperature at a constant level, regardless of the weather. Insects, amphibians, reptiles, snails and others cannot do this - they therefore fall into temperature-induced torpor as soon as the temperatures drop below ten degrees Celsius in autumn. The body temperature of these species is also at a correspondingly low level - analogous to the outside temperature. Winter torpor is a hibernation strategy of cold-blooded animal species.
What are the differences between hibernation and hibernation?
The body temperature of frogs and other cold-blooded animals drops sharply in winter
The differences between hibernation (which dormice and marmots have, for example) and hibernation (for example, in frogs and toads) are significant. The following table shows you which characteristics are characteristic of these two wintering strategies and of hibernation.
| hibernation | Winter torpor | Winter rest | |
|---|---|---|---|
| Animal species | few animals of the same temperature | ectothermal animals | many animals of the same temperature |
| Body temperature | drops sharply | decreases analogously to the outside temperature | remains more or less consistently normal |
| Body Functions | Heart rate and breathing are greatly reduced, death-like state | Heart rate and breathing are greatly reduced, death-like state | Heart rate and breathing remain at normal levels |
| Signal for hibernation / waking up | chronobiological, independent of the outside temperature | depending on the outside temperature (for most species below 10 °C) | chronobiological, independent of the outside temperature |
| Waking up / eating in between meals | occasional short periods of wakefulness, in some species feeding is possible (e.g. when supplies have been built up) | only possible if the temperatures rise again in the meantime | long awake phases with regular food intake, shorter rest phases |
| Can you wake up? | yes, in case of external disturbances | no, as long as the temperatures remain below the critical value | yes, in case of external disturbances |
| Movements | occasionally possible | no movements possible as long as the temperatures remain below the critical value | yes, often |
| Problems | Waking up early / waking up leads to hunger due to lack of food | no waking up in frost, winter-hardened animals freeze to death when it gets too cold | Food shortage in winter |
Chronobiological in this context means that the start signal for hibernation or the signal to wake up from it is not or only to a small extent determined externally. Instead, hibernating animals follow their internal clock and go into hibernation at the right time of year, even when it is not that cold outside. Cold-blooded animals, on the other hand, only go into hibernation when the outside temperature falls below a critical value - for many species this is around ten degrees Celsius.
Which animals hibernate?
In contrast to hibernation - the animals that actually hibernate can basically be counted on two hands - many cold-blooded species fall into hibernation. Only a few of these animals, such as the honey bee, have developed other overwintering strategies. In this section we will discuss who hibernates and how.
Insects
Wie Tiere durch den Winter kommen | NaturNah | NDR Doku
Winter torpor is characteristic of many insect species, although there are different forms between the different species.
- Mosquitoes: Here only the females overwinter in cool and damp places, the males die in autumn.
- Wasps: Only the young queens overwinter, the rest of the colony dies in autumn.
- Bumblebees: the same strategy as wasps, only the young queens hatched in late summer overwinter
- Ants: hibernate as a colony in the underground part of the anthill, the visible pile above ground serves as protection from the cold
- Butterflies and moths: usually do not overwinter as an adult, but as an egg, larva or pupa. Adult butterflies usually die after a few weeks and only a few species go into hibernation. A few species such as the Painted Lady butterfly migrate to warmer regions in autumn like migratory birds.
- Beetles: Adult beetles hide in protected places, for example in tree bark and holes, cracks in walls, in piles of leaves and brushwood. Some species do not hibernate at all, only their eggs, larvae or pupae wait out the winter (e.g. May beetles).
Excursus
The special path of the bees – everything for the queen
Basically, honey bees also go into hibernation. However, these animals have developed a different strategy to survive the winter as a colony - and to keep their only egg-laying queen alive. During the cold season, all individuals huddle closely together and keep the temperature in the hive always cozy and warm by constantly shivering. The ones on the outer edge in particular provide warmth. If they get tired after a while, they will be replaced. The queen is always in the middle. The situation is different for wild bees, who often live solitary lives; they spend the winter frozen in the ground.
Spiders
The numerous species of spiders have also developed very different hibernation strategies. Some people look for a warm place for the winter months and hide in the basement or living room, for example. Water spiders use a particularly interesting method: They hide in an empty snail shell, close the opening with their tissue and spend the winter floating on the surface of the water, protected. Other arachnids, such as the unloved ticks, also fall into hibernation. When temperatures drop, these retreat to their winter quarters - such as piles of leaves, mole burrows, mouse nests or fox burrows.
Amphibians
Frogs and toads are amphibians. Most species hibernate on land and require suitable winter quarters that protect against frost if necessary - because these animals do not survive freezing temperatures for long. A typical hiding place for common toads is the compost heap in the garden, otherwise the animals prefer the following places:
- damp holes in the ground, such as mouse or mole tunnels
- Hollows under tree roots
- Vacities under wood or stones
- Cracks and cracks between stones and rocks
- Pile of leaves and brushwood
Some species of frogs - for example the common frog or the pond frog - hibernate in stagnant water. They burrow into the mud at the bottom of the pond, as long as the pond is deeper than at least 80 centimeters - it doesn't freeze here even in sub-zero temperatures.
Reptiles
Many turtle species also fall into hibernation if you let them
“Animals that are allowed to hibernate live longer. This is especially true for turtles kept as pets!”
In addition to turtles and snakes, this group also includes lizards and other lizards. Native species such as the rare European pond turtle, the sand lizard, grass snakes, adders and slowworms all spend the cold season in hibernation. How long this lasts varies from species to species and also depends on the weather:
- Blindworm: spends four to five months in hibernation
- Adder: same as slowworm
- Sand lizard: five to six months
- grass snake: around six months
- European pond turtle: four to five months
By the way, the European pond turtle, like pond frogs, hibernates at the bottom of ponds and other stagnant bodies of water.
Fish
Most fish species do not go into hibernation, but remain awake during the cold season. How do these animals survive the winter? They sink to the bottom of the pond or, like the tench, burrow into the mud. During the winter, the aquatic inhabitants find little food, which is why they essentially live on the layer of fat they eaten in the summer. If you keep pond fish, you should dig the fish pond at least 80 centimeters deep - preferably more - so that it does not freeze to the bottom. This would be fatal to overwintering fish.
Excursus
How do cold-blooded animals protect themselves from deadly frost?
Ecothermal animals do not survive frost because their body fluids also freeze and they die as a result - there is no protective mechanism in these species analogous to hibernators of the same temperature, whose body temperature is kept at a constant level even in extreme cold. However, insects, snakes, frogs and the like have found another way to survive even in light frost: In winter, they increase the glucose concentration in the blood and other body fluids so that they cannot freeze - so they practically use the body's own antifreeze However, it only helps with low frosts. Therefore, a frost-proof winter quarters is important for the survival of these species.
Frequently asked questions
I found a butterfly in the living room. What do I do with him?
Moths and butterflies sometimes get lost in living spaces in autumn
As soon as it gets cooler in autumn, animals look for suitable winter quarters. During this search they often get lost in houses and apartments. However, if you find a butterfly or a ladybug here, their chances of survival in the heated living room are not very high. It is best to bring the winter-hardened animal to a cool (but frost-free!) and quiet room, such as the basement or garden shed. These insects don't survive outside either, it's simply too cold there.
Is it true that turtles can overwinter in the refrigerator?
Since turtles should keep their hibernation at constant temperatures of around five degrees Celsius, experts actually recommend overwintering in a refrigerator. However, for hygiene reasons, it is not enough to simply shove the animal into the kitchen refrigerator. Instead, owners should either purchase one specifically for the turtles or have the animals overwinter with a veterinarian. Some offer this service, which brings with it a whole range of benefits - such as the fact that the hibernating turtles are continuously monitored.
Do turtles kept as pets absolutely have to overwinter?
Inexperienced turtle keepers in particular deny their animals hibernation or delay it as much as possible. They want to prevent the turtles from dying during the hibernation period, which is considered dangerous. The opposite is the case, because the mortality rate is particularly high in winter-awake specimens. Delaying hibernation is also dangerous, as the animals' metabolism changes in November - if they are not allowed to follow the natural process, a variety of he alth problems arise.
I found motionless ladybugs. Are they still alive?
Unfortunately, it can only be found out at the beginning of spring whether the ladybug is dead or just frozen in winter. Since animals cannot be awakened from their hibernation and there are no other characteristics to distinguish them, simply leave the specimens you find in their place or take them to suitable quarters. This must be cool, but not at risk of frost.
Tip
Suitable winter quarters are important for many garden beneficial insects. Therefore, leave piles of leaves and brushwood lying around in late summer, offer insect hotels or build a natural stone wall.
