Hibernators maintain a constant temperature for most of the year, but greatly lower their metabolism in response to environmental cues for a few days or weeks. these are referred to as:

Cold blooded animals (Poikilotherms).

These animals do not have homeostatic regulation of their body temparatures like the warm blooded (homeotherms). This physiology allows them to Vary their physiological metabolisms when required.
Hibernating animals, for example, can lower their metabolism and physical activities during winter when temperatures are low