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Why can a lack of food or water cause dormancy?

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The image shows a group of Virginia big-eared bats sleeping upside down in a dark cavern. — Dormancy Virginia big-eared bats (*Corynorhinus townsendii virginianushibernating*) are true hibernators, entering a state close to death for much of the winter.

In biology, dormancy is an adaptive mechanism characterized by a state of reduced metabolic activity that allows organisms to survive periods of environmental stress. A lack of food or water serves as a critical trigger for this state because it signals that the current environment is no longer sustainable for normal activity.123

When resources such as food or water become scarce—often due to seasonal changes like drought or extreme cold—organisms enter dormancy to conserve their limited energy reserves. By lowering their metabolism, they make fewer demands on their environment, allowing them to endure until conditions improve. For example, when aquatic habitats dry up, some organisms enter dormancy to avoid perishing. Similarly, animals in arid regions may undergo estivation during hot, dry summers to survive the lack of water and food.1324

This strategy is essential for survival, as it enables organisms to bridge the gap between unfavorable conditions and the return of a more hospitable environment, effectively allowing them to occupy niches that would otherwise be untenable.23