The poikilothermic animals (more recently called ‘ectotherms’) are those that regulate their temperature from the ambient temperature. For instance: lobsters, butterflies, crickets.
This happens because they do not have the characteristic of many other organisms, which is to be able to regulate their body temperature generating heat: this is why these types of animals are often called ‘cold-blooded’ animals. The animals that are not poikilotherms are the ‘homeotherms’ (or ‘endotherms’), within which all mammals stand out.
Characteristics and behavior of poikilotherms
In general, the smallest poikilotherms adjust to room temperature, but there are some of them that can limit the extreme temperatures from the thermal behavior, and it is then that they modulate the short-term influence of the temperature variability.
Recently some scientists have found that daily fluctuations in the prevailing temperature, they alter the sensitivity of the species to warming caused by climate change, through a decrease in the thermal safety margins.
Advantages and disadvantages of poikilotherms
While endothermic animals generate heat from the energy contained in the food, ectotherms do not have to feed every day and may even be able to go months without feeding.
This provides them with a advantage, which is counteracted by the fact that they cannot inhabit environments with extreme temperatures, because they are highly dependent on environmental changes: endotherms, on the other hand, can live in colder or warmer habitats.
As in ectotherms the regulation of temperature depends on the ability to regulate the exchange of heat with the environment, it is common that some must be produced for thermoregulation. These are divided into two groups:
- Behavioral adjustments. They are the changes in behavior looking for areas in the environment where the temperature is favorable to the activities. There are some species that are called euthermic, which can live within fairly wide ranges of body temperature.
- Physiological adjustments. They are those that modify metabolic rhythms at the prevailing temperature, in such a way that the intensity of metabolism is not modified. This type of animal performs a temperature compensation that allows them to have the same level of activity in environments of different climates: they resemble endotherms, directly regulating their metabolism regardless of body temperature.
There are some cases of animals that are not ectothermic, but that have similar behaviors.
- Regional endothermy. For example, it occurs when the temperature of the heart and gills changes with changes in environmental temperature, as happens in some groups of fish.
- Facultative endothermy. On the other hand, it occurs frequently in insects that can produce heat with the trembling of their muscles, raising their body temperature for a certain time.
Examples of poikilothermic animals
- Cordylus lizard
- Galapagos marine iguana
- Desert lizards
- Desert iguana