Difference Between Cold Blooded and Warm Blooded

Let us know about the terms cold blooded and warm blooded before knowing the difference between these two categories.

Cold Blooded and Warm Blooded

  • Cold-blooded Animals: Animals that cannot regulate their internal body temperature according to that of the changing environment. Normally, they find it difficult to survive the extreme temperature conditions.

           Examples include reptiles and fish. 

  • Warm-blooded Animals: Animals that can regulate and maintain a constant internal temperature of the body. Warm-blooded animals can maintain constant internal body temperature and survive in any temperature range as they adapt to the harsh conditions of any kind of environment.

            Examples include birds and mammals including humans.

Cold Blooded and Warm Blooded Animals

A popular term associated with cold blooded and warm blooded animals is thermoregulation. Thermoregulation is an organism’s ability to keep its body temperature within certain boundaries, even when they have to face different temperatures in varied surroundings. Thermoregulation is divided into different types including Endothermic (homeothermic or warm-blooded) or Ectothermic (poikilothermic or cold-blooded). 

  • The endothermic (warm-blooded) and ectothermic (cold-blooded) categories of animals either make their own heat or they get it from the environment.  

  • Homeothermic and Poikilothermic animals describe whether the temperature is constant. 

  • Homeothermic animals have constant body temperature regardless of external influence and they normally have high body temperature. Homeothermic animals are endothermic or warm blooded animals. Examples include birds and mammals. Therefore humans belong to the endothermic homeotherms as we produce our own heat and maintain it ourselves and it’s done through metabolism. 

  • Poikilothermic animals are opposite to that of homeothermic animals as their internal body temperature keeps changing; and cannot regulate their own body temperature, rather depend upon the environment to regulate. Poikilothermic are ectothermic or cold blooded animals. Examples include animals (vertebrates), we can see how lizards and reptiles take sunbaths to warm up their bodies to make their muscles or brain work.

  • One more interesting term to know related to body temperature is mesothermic and this category of animals such as dinosaurs used to create and maintain their own body heat as well as utilise their environment. 

Animals like fish, amphibians, most invertebrates and reptiles are ectothermic poikilotherms  since they get heat from the environment and let their body temperature fluctuate. 

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The differences between warm and cold blooded animals can be clearly understood with the following tabular representations.

Difference Between Warm Blooded and Cold Blooded Animals


Warm Blooded Animals

Cold Blooded Animals

Body Temperature

Keep its body temperature the same no matter what the outside temperature is, ir.e. They can maintain a constant body temperature.

Their internal body temperature gets hotter or colder based on the temperature outside. So, they cannot maintain constant body temperature.


Example- Mammals and birds

Reptiles, insects, and fish (amphibians)


They obtain energy from food consumption.

They obtain energy from the surrounding environment.

Effect of Body Fat

Fat is pretty important for mammals or hot blooded animals as it helps animals like seals and whales to keep warm in the freezing oceans.

Here, more fat causes overheating of the bodies that may also result in death.

Chances of infections or diseases

The constant heat of the bodies provide a perfect incubator for germs and are prone to get sick or infections.

Cold blooded animals do not cultivate the germs easily thus preventing infections. However, if the bodies are cold for too long they will be unable to fight off infections and disease.


Endothermic creatures can live anywhere at ease usually by adding/removing extra layers of clothing in cold temperatures. Humans can even survive the coldest temperatures of Antarctica.

It’s not the case in cold blooded animals as they cannot regulate the body temperature according to the environment.

Body Temperature

Most of this category of animals maintain a body temperature of around 37 degrees Celsius. 

A cold-blooded creature has exactly the same body temperature as its environment.


Brains get activated for mammals with the intake of food that produces heat and energy. And they adjust by sweating, shedding or panting when the temperature is hot outside.

Cold blooded creatures like lizards are lazy and only come out in the sun for heat to get their brains to work properly.

Metabolism Rate

They don’t change their metabolic rate with the environmental changes.

They change metabolic rates with changes in the environment.

Extreme Temperatures

They easily adapt to any temperatures outside.

It’s difficult for them to survive in extreme temperature conditions.

FAQ (Frequently Asked Questions)

1. Explain Cold Blooded vs Warm Blooded Animals.

Here is the difference between warm blooded and cold blooded animals explained for you. Cold blooded animals are those animals that cannot regulate their body temperature and their temperature keeps changing according to their environment. Some of the examples of cold blooded animals include fish, reptiles and insects. Warm blooded animals are the animals that have a constant body temperature and can easily adapt to extreme temperatures as they can regulate their body temperature. Examples of warm blooded animals include birds and mammals including human beings.

2. What do you Mean by Endothermic Animals?

Endothermic is another name for warm blooded animals that can regulate their internal body temperature as they make their own heat and don’t depend upon the environment for regulation.

3. What do you Mean by Exothermic Animals?

Exothermic is another name for cold blooded animals who cannot regulate their body temperature by their own and depend upon the environment. Their body temperatures are exactly the same as that of their environment.

4. What is the Meaning of Cold-blooded Animals?

Cold blooded animals like fish and lizards depend upon the environment to regulate their internal body temperature. If it's sunny outside, lizards often come out and take sunbathes to keep themselves warm. And they are cold if the temperature is cold outside. Therefore, they cannot stand extreme temperatures outside and it is difficult for them to survive in such conditions.

5. What is the Meaning of Warm-blooded Animals?

Warm blooded animals like humans and birds regulate their own body temperature that remains constant irrespective of the outside environmental temperature.