Hibernation

Banded Little brown bat

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A bat (Northern bat) hibernating in Norway

Yellow-bellied Marmot on Tundra Rocks

Hibernating Virginia big eared bats in cave

Hibernation is a state of prolonged inactivity observed in some endothermic (or warm-blooded) animals. This physiological adaptation enables these creatures to survive during periods, typically winter, when food is scarce. While in hibernation, animals experience significantly reduced metabolic rates, body temperatures, respiratory rates, and other essential functions, allowing them to conserve energy.

Overview

During hibernation, the animal's metabolic processes adjust to conserve energy. This adaptation is crucial as it relies primarily on fat reserves accumulated during summer and autumn for sustenance. As winter approaches, these animals undergo a preparatory phase where they consume vast amounts of food to store fat, which then sustains them during their dormant period.

Mammalian Hibernators

Various mammals exhibit hibernation behavior, including:

• Bats
• Ground squirrels (e.g., marmots)
• Hedgehogs
• Some marsupials

The duration and depth of hibernation, often referred to as torpor, vary among species. For example:

• Hedgehogs: Enter a torpid state for 1-3 weeks without waking.
• Fat dormouse: Remains in torpor for 20-33 days without any signs of waking.

During these periods of deep sleep or torpor, the animal's body temperature drops significantly, matching or even going below the ambient temperature, and their vital functions decelerate, all in an effort to decrease energy consumption.

Birds and Hibernation-Like States

While hibernation is typically associated with mammals, certain birds exhibit behaviors reminiscent of hibernation. For instance, some species of Kolibris (hummingbirds) enter a hibernation-like state, conserving energy when food is scarce.

See Also

• Torpor
• Endothermy
• Metabolism
• Adaptation