Poikilothermic animals (called in a more recent form ‘ectotherms’) are those that regulate their temperature from the ambient temperature.
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 usually called ‘cold-blooded’ animals. The animals that are not poikilotherms are the ‘ homeotherms ‘ (or ‘endotherms’), among which the totality of mammals stands out.
Characteristics and behavior
In general, the smallest poikilotherms are adjusted to the ambient 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 alter the sensitivity of species to warming caused by climate change, through a decrease in thermal safety margins.
Advantages and disadvantages
While endothermic animals generate heat from the energy contained in food, ectotherms do not have to feed each day and may even be able to be months without feeding.
This provides them with an advantage, which is counteracted by the fact that they can not 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.
Adjustments of poikilotherms
As in ectotherms, temperature regulation depends on the ability to regulate the exchange of heat with the environment, it is common that some should be produced for thermoregulation. These are divided into two groups:
- The behavioral adjustments are behavioral changes in the environment looking for areas where the temperature is favorable to activities. There are some species that are called euthermic, which can live within fairly wide ranges of body temperature.
- The physiological adjustments are those that modify the metabolic rhythms to the prevailing temperature, in such a way that the intensity of the metabolism does not change. This type of animals compensates for the temperature 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 ectotherms, but that have similar behaviors.
- The regional endotherm , for example, occurs when the temperature of the heart and gills changes with changes in environmental temperature, as in some groups of fish.
- The facultative endothermy , on the other hand, occurs frequently in insects that can produce heat with the tremor of their muscles, raising their body temperature for a certain time.
Examples of poikilothermic animals
- Cordylus Lizard
- Marine Iguana from the Galapagos Islands
- Desert Lizards
- Iguana of the desert
- Naked mole-rat (the only mammal that is a poikilothermic animals)