I have learned a new word: aestivation (alternate form: estivation).
Aestivation is the opposite of hibernation. It’s a “state of animal dormancy, characterized by inactivity and a lowered metabolic rate, that is entered in response to high temperatures and arid conditions. It takes place during times of heat and dryness, the hot dry season, which is often but not necessarily the summer months. (With thanks to Wikipedia.)
I love this new word and have been using it now that it’s hell-hot here in Virginia.