You have probably at least once wanted to sleep through the could winter days, when temperatures drop to ten degrees below zero. We can only envy bears or squirrels, who have been sleeping in deep sleep for some time, spending cold days carefree and tucked away. But, have you ever wonder how they managed to sleep through the whole winter and what exactly is hibernation?

Summer dream

Some animals fall into summer dream , the so-called estivation, in order to avoid great drought in summer. Such are, for example, the lung fish, which are buried in the river mud during the drought, until river is again refilled with water.

The fat-tailed, dwarf lemur from Madagascar is the first primate in which it was discovered that it can be in state of hibernation for as long as seven months during the year. This cute animal falls asleep due to extremely high temperatures that occur on the island in Southeast Africa during that period.

Hibernation in lemurs mainly depends on their shelter, a hole in the tree, in which they spend most of their lives. Namely, if the hole is well insulated, the temperature of his body is mostly constant, otherwise, it varies in order for the organism to adapt to external condition.

Hibernation is state of reduced activity of plants and animals that live in extratropical regions of the world, during severe winter conditions. In this state, they store energy during cold weather while their food sources are limited.

Metabolic depression

Some animal hibernate during winter. Hibernation is a special type of very deep sleep and represent a state of inactivity and metabolic depression specific to endotherms, organisms that have the ability to independently maintain the best possible metabolic body temperature.

Metabolic depression is is an adaptive biological process responsible for storing energy in the body during which the animal's body temperature drops, and blood pressure, respiration and metabolism slow down. It can last from a few days, weeks, months, depending on the species, ambient temperature, season and individual body conditions.

The term hibernation was previously associated only with so-called deep hibernators, such as rodents, whose main feature is the reduction of absolute temperature body. Later, the meaning was modified and now applies to all living beings whose metabolism slows down during harsh winter conditions. Animals such bears, squirrels, skunks and and some species of bats are now classified as hibernators.

Winter dream

In the fall, the animals prepare for hibernation by eating more food than usual and the storage is in the form of body fat , which they use as an source of energy during sleep. Most of them fill their lairs with food supplies, so that they can eat during the winter as well.

Cold-blooded animals such as snakes, fishes, frogs and turtles can never kept their bodies warm in winter. They find shelter in holes and dens by spending cold periods inactive or dormant, representing states similar to hibernation.

In addition to animals, some species of plants also hibernate. Such is, for example, deciduous trees. Just before the winter period, when the temperature is lower and the number of sunny hours during the day decreases, the leaves of these plants fall. Years on trees one of the consequences of hibernation, because the growth of trees is faster during summer period, when the conditions for food production are better.

Biennial and perennial herbaceous plants, such as carrots, discard sensitive parts above the surface of the earth before the winter period and which renew themselves when warmer weather conditions occur.

Images source: Wikimedia Commons

Literature: Elementarium