Difference Between Ectotherms and Endotherms (With Table)

A reptile, or an amphibian as pets demand more attention and care than a dog or a cat. As its health depends upon the environment unlike a dog’s, or a cat’s health. This is because they need proper heat, humidity, as well as diets, as each amphibian, or reptile is adaptive to its specialized, or a specific food, it is vital for the keeper to be aware of their family history.

Reptiles and Amphibians take their heat from the environment i.e. their surroundings for many biological processes such as consumption of food, and immunity to fight diseases. If their surroundings are not warm enough they might not be able to fight infections and digest any of their food into their systems.

Ectotherms vs Endotherms

The main difference between Ectotherms and Endotherms is that the Ectotherms are organisms (including reptiles and amphibians) that cannot generate heat by themselves, due to which they are dependent upon the environment. Whereas, on the other hand, Endotherms are the organisms that possess the ability to keep themselves warm, without any external assistance.


Comparison Table Between Ectotherms and Endotherms (in Tabular Form)

Parameter of Comparison




Ectotherms are creatures that depend upon the external source for their body heat.

Whereas, Endotherms are those organisms that create the heat needed for their body, internally.

External temperature

Ectotherms are affected by the external temperature, as it fluctuates with its internal temperature.

On the other hand, an Endotherm’s body temperature does not fluctuate with external temperature.

Known as

Ectotherms are known as cold-blooded animals, or poikilotherms.

Whereas, on the other hand, Endotherms are referred to as warm-blooded animals, or homeotherms.

Stamina and metabolism

Ectotherms have lower stamina in comparison to Endotherms. Moreover, it has anaerobic metabolism.

On the contrary, Endotherms have greater stamina as compared to Ectotherms, and have aerobic metabolism.


Snakes, turtles, lizards, and alligators are examples of ectotherms.

Whereas, Mammals, humans, polar bears, penguins, etc.


What are Ectotherms?

Ectotherms are the organisms that have a small, or low level of internal heat generation, therefore, they absorb heat from the external sources i.e. their surroundings. Some ectotherms live in an environment where the temperature is constant. Whereas, the places where the temperature varies, the animals bask in the sun to in-take the heat, to perform activities, and sometimes they limit their physiological activities to preserve their energy.

The fluctuating temperature affects the body temperature of Ectotherms as well, such variation is known as Poikilothermy, which gives out another name for Ectotherms, which is Poikilotherms. There are distinct body patterns of ectotherms, for example, reptiles, as well as many insects, adopt positions in a way that they get maximum sun exposure, or seek shelter.

In addition to body patterns, or behavioral change, there are also physiological changes that help Ectotherms to regulate their body temperatures.

During winters, or cooler temperatures, some Ectotherms enter into hibernation, or state of torpor which may last for a day, or a year depending upon the species, and hence they restrict their movement, and some might not be able to live through the season, as their metabolism rate, as well as body temperature decreases and in some animals like wood frogs, their metabolism stops. Hibernation helps such animals to survive, as it allows them to live without food for a long time.


What are Endotherms?

In Greek, Endon means internal, and as the name suggests Endotherms are the organisms that regulate their body temperature, internally. They maintain their body temperatures at a temperature that is favorable for their metabolism. The internal heat is a result of the animal’s routine metabolism.

Unlike Ectotherms, Endotherms do not get affected by the external temperature i.e. the location does not affect their body temperature, they sustain their core temperatures to keep their metabolism working. Endotherms are active in both day, and night, unlike Ectotherms who become sluggish in the night, and come out of their shelters in the morning to absorb the heat from the sun.

The metabolism rate increases with the increase in the external temperature, and hence they require more food in warmer temperatures. To avoid the problem of overheating the animals lose the body heat by “panting” which cools off the animal’s body. Whereas, hairless, as well as, short-haired mammals, for example, humans “sweat” to lose the heat, as the heat is evaporated through sweat. Elephants use their tremendous ears to increase the air-flow which reduces their core temperature.

Main Differences Between Ectotherms and Endotherms

  1. Ectothermic animals gain heat from the external source, while, on the other hand, endothermic animals absorb heat from their metabolism.
  2. Ectothermic organisms have a body temperature the same as their environment, on the other hand, Endothermic organisms regulate their body temperature as per the surroundings.
  3. The food intake of Ectothermic organisms is less as compared to Endothermic organisms.
  4. Ectothermic animals tend to become sluggish due to the need for hibernation, while, on the other hand, Endothermic animals can inhabit in cooler temperatures.
  5. Ectothermic animals require less food, on the contrary, endothermic animals require more food in warmer temperatures as their metabolic rate increases with temperature.



All chemical reactions involve the relocation of energy, the chemical energy is often released in the form of heat, such reactions are of two types, Ectothermic reaction and Endothermic reaction. The chemical energy is converted into mechanical energy, and heat, which is then utilized in day-to-day activities such as digestion of food. Ectothermic and Endothermic are contrary reactions, in which the former denotes the reaction in which the heat is absorbed by the external sources, while the latter generates the energy from within i.e. through their biological systems.

In the case of Endotherms, like the rat, generates metabolism heat to maintain the internal temperature, while, on the other hand, Ectotherms, for example, the snake, has a body temperature that changes with the temperature of its surroundings.


  1. https://link.springer.com/article/10.1007/BF00175505
  2. https://www.physiology.org/doi/abs/10.1152/ajpregu.1996.271.5.R1287