Poikilotherms

Poikilotherms, often incorrectly called 'cold-blooded' animals, are organisms whose internal body temperature varies considerably and is largely dependent on the ambient environmental temperature. They lack the internal physiological mechanisms to maintain a constant core temperature and must rely on external sources of heat or cooling to regulate their body temperature. This includes behavioral adaptations like basking in the sun or seeking shade. The term encompasses a wide range of organisms, from invertebrates to certain vertebrates, including most fish, amphibians, and reptiles. Their metabolic rate, and therefore activity level, fluctuates significantly with temperature changes; warmer temperatures generally lead to increased activity, while colder temperatures lead to slower metabolisms and reduced activity.

Poikilotherms meaning with examples

• The sluggish movement of the lizard in the early morning was due to its poikilothermic nature, its body temperature still reflecting the cooler night air. As the sun warmed the rocks, the lizard’s metabolism increased, allowing it to hunt with greater speed and agility.
• Fish, being Poikilotherms, thrive in stable aquatic environments where the water temperature remains within their preferred range. Drastic temperature fluctuations can stress their systems, impacting their feeding habits and reproductive cycles.
• Frogs, Poikilotherms of the amphibian class, spend the winter in a state of dormancy, where their body temperature slows and they enter a state of brumation to conserve energy. This behaviour is essential for survival in colder climates.
• Researchers studying Poikilotherms in the desert found that the diurnal cycle of the animals was tied to thermal regulation. The animals would be active in the cooler parts of the day and mostly inactive during the hottest times, limiting heat stress.