Difference Between Cold Blooded Animals and Warm Blooded Animals


Main Difference

Cold blooded animals don’t have an internal mechanism to regulate their body temperature while warm blooded animals keep their body temperature by using internal homeostasis system at a constant level regardless of external temperature.

Comparison Chart

Cold Blooded AnimalsWarm Blooded Animals
Animals who cannot consume their metabolism system to maintain body temperature are called cold blooded animals.Animals who maintain their thermal homeostasis regardless of the ambient temperature are called warm blooded animals.
Other Names
Also known as ecotherms, poikilothermal animalsAlso known as endotherms, homeothermal animals.
Amphibians, Reptiles, and fishBirds, mammals
Frog, LizardHuman, Polar-bear
Greek words (ektos: outside), (thermos: hot)Greek words (endo: inside) , (thermos: hot)
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Cold Blooded Animals:

Cold blooded animals are animals in which internal physiological heat sources are small or less important in controlling body temperature. These animals depend on external environmental heat source which permits them to operate at very economical metabolic rates. These animals are lazier at nights and in early mornings. When they emerge from their shelter, many cold blooded animals need to heat up before beginning their daily activities. In the cold season, the foraging activity of cold blooded animals is restricted to the day time in most vertebrate ectotherms and in cold climate most can not survive at all. In lizards, for example, most nocturnal species use “sit and wait” foraging strategies. These techniques do not require as much energy as an active method and do not need hunting activity of the same intensity. Cold blooded animals have to conserve their internal energy. Hibernation is a strategy which enables ectoderms to save energy when food is scarce. During hibernation, body temperature drops, breathing, and heart rates slow, and most of the body’s metabolic functions are put on hold in a state of quasi-suspended animation. Aestivation is another form of cold blooded animals’ dormancy in summer season (Latin word: aestas meaning summer). Animals aestivate in hot and dry weather.


Warm Blooded Animals

Warm blooded animals use internal metabolic processes, environmental factors to fluctuate overall body temperature and maintain body temperature at a narrow range. Heat is usually produced from the animal’s normal metabolism, but in cold conditions, warm blooded animal generates extra heat by shivering. These animals have a large number of mitochondria per cell. Mitochondria enable them to produce heat by increasing the rate of fats and sugar metabolism. Warm blooded animals must sustain their high rate of metabolism by eating extra food. For example, a mouse (warm blooded) must eat food every day to maintain high metabolism while snake (cold blooded) must eat only once in a month. Thermoregulation is also important to protect internal enzyme system. Because as the internal temperature increases, internal enzyme activity increases at first but then denature at higher temperatures and lose their physiological functions. When internal temperature decreases, hypothermia occurs and some other body functions are affected, so thermoregulation is important. For thermoregulation, heat can be exchanged between animal and its surrounding environment via four mechanisms; evaporation, radiation, conduction and convection. When an animal sweats, evaporation removes heat from the surface of the skin with liquid. Radiation is the emission of electromagnetic heat waves. Heat radiates from the sun and from the dry skin the same manner. In conduction, heat can be conducted from one surface to another surface during direct contact with the surfaces such as animal resting on a warm rock. Convection currents of air remove heat from the surface of the dry skin as the air passes over it.

Cold Blooded Animals vs. Warm Blooded Animals

  • Cold blooded and warm blooded terms are used to distinct animals from each other
  • Cold blooded animals show hibernation (winter sleep) and aestivation (summer sleep)
  • Warm blooded animals rarely show hibernation and aestivation.
  • Cold blooded animals move slowly for the regulation of the internal
  • Warm blooded animals move fast and loose significant amount of energy to keep their muscles warm.
  • Cold blooded animals depend on external sources to maintain
  • Warm blooded animals rely on internal body system to maintain thermoregulation constant.
  • Cold blooded animals usually live in an environment of constant temperature for example tropics or ocean.
  • Warm blooded animals have developed various behavioral thermoregulation mechanisms, for instance, seeking shade to decrease body temperature, basking in the sun to increase body temperature.
Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White