Henothermism

Henothermism is a biological concept referring to the ability of some animals to maintain a body temperature that is not directly regulated by their external environment, but is also not as stable or high as that of endotherms. It represents a state intermediate between ectothermy, where body temperature largely depends on external sources, and endothermy, where body temperature is internally generated and tightly regulated. Animals exhibiting henothermism may rely on a combination of behavioral thermoregulation, such as basking in the sun or seeking shade, and internal physiological mechanisms that can elevate their body temperature to some extent. This internal heat production might be less consistent or powerful than that of true endotherms.

The term henothermism is sometimes used interchangeably with "mesothermy," though subtle distinctions may exist in scientific literature. It describes a strategy where an organism can achieve elevated body temperatures under certain conditions, allowing for increased metabolic rates and activity levels compared to strict ectotherms, without the high energetic costs associated with constant endothermy. This can be advantageous in environments with fluctuating temperatures, providing a degree of thermal independence that allows for more flexibility in foraging and predator avoidance. However, henothermic animals typically still experience greater fluctuations in body temperature than endotherms and may be more susceptible to extreme environmental conditions.