What is the summer counterpart of hibernation?

The summer counterpart of hibernation is estivation. Also spelled aestivation, it is a dormant or low-activity state that helps animals survive hot, dry conditions. During estivation, an animal may lower its metabolic rate, reduce movement and conserve water until temperatures or seasonal conditions improve.

Estivation is not limited to one animal group. Land snails may retreat into their shells and seal the opening with a dried mucus layer called an epiphragm. Some amphibians, reptiles, insects and fish also estivate. The African lungfish, for example, can survive dry periods buried in mud, while certain frogs remain underground inside protective, moisture-retaining coverings.

The key difference from hibernation is the environmental challenge being avoided: hibernation is most strongly associated with winter cold and food scarcity, whereas estivation is associated with summer heat, drought and dehydration. Both are forms of dormancy, but neither necessarily means ordinary sleep. Animals can rapidly resume activity when favorable conditions return.