Are Reptiles Cold-Blooded? Regulating A Reptiles Requirements

Anusuya Mukherjee
Oct 19, 2023 By Anusuya Mukherjee
Originally Published on Oct 29, 2021
Lizard families together.

Reptiles are animals that belong to the Reptilia class .

Reptiles are generally recognized from their skin, which has scales and a multitude of colors. Most reptiles on our Earth are ectothermic (cold-blooded).

Most reptiles are oviparous, meaning they lay eggs to give birth, unlike mammals. Complete growth of the fetus takes place inside the egg instead of a womb.

The species belonging to the family of reptiles include animals like turtles, snakes, lizards, crocodiles, tortoises, and more. They are generally classified as tetrapod vertebrates (species who have four limbs, or are descended from animal ancestors that had four legs).

After reading various facts around reptiles, do check: are frogs cold-blooded and cold-blooded animals.

Are reptiles endotherms?

Most reptiles belong to a category of animals called ectotherms, not endotherms. The word 'endo' means outer or outside, while ‘therm' means heat, as derived from the Greek language. Endotherm is derived from the combination of the words ‘internal’ or ‘inside’ and ‘therm’ for heat.

Reptiles are cold-blooded or ectothermic, meaning they depend on external environmental factors like temperature, humidity, and so on, to regulate their body temperature. Endotherms, like us, maintain a single body temperature throughout the year, which is generated from the food they eat daily. The process of metabolism keeps this heat constant.

In ectotherms, the animals largely rely on environmental temperatures and other sources of heat to maintain their body temperature.

Their metabolism and immunity depend on optimal level conditions pertaining to the environment, its temperature, and humidity. If they get too cold, they lie in the sunlight in the day to heat up their bodies and, if they get too hot, they find cool, shady places to hide from the sun in order to cool down.

Their internal physiological sources are mostly useless in forming heat within the body, which is necessary for so many bodily functions like digesting food.

What does ‘cold-blooded’ mean?

Cold-blooded animals are classified as ectothermic, meaning they depend on the environment to regulate their body temperature. As they cannot produce their own body heat, reptiles are generally ambush predators, who expend very little energy for tasks like hunting.

Because of their low metabolism levels, reptiles like snakes can survive by eating only once or twice a fortnight, depending on their species.

When temperatures and other environmental conditions fluctuate constantly or change with the seasons, many reptiles hibernate, meaning they hide and sleep for a long time in places that have zero to extremely minimal changes in temperature and atmosphere.

They can bring their body temperature very low and slow down systems like metabolism to preserve energy for the most necessary systems like breathing.

They can spend months like this, sometimes even years, until the surface conditions are back to an environment which is suitable for these reptiles.

Regulating A Reptile's Body Temperature

There are many people who love to keep pet animals like lizards, geckos, or snakes. One of the key differences of having such pets compared to mammals or warm-blooded pets is to give constant attention to the temperatures, environmental conditions, heat, and humidity where the pet reptile is kept.

While having a pet animal is a very interesting experience, one should also see to it that the species of snake, gecko, turtle, or lizard they are getting is suitable for keeping under controlled conditions inside a cage or a box.

Keeping a reptile that is too exotic for one’s regular surrounding environment might just be very painful and uncomfortable for the pet reptile.

Having said that, some reptiles are easy to look after within enclosed spaces under controlled conditions, like eastern box turtles, or a leopard gecko.

All reptiles have a preferred optimal temperature range, which affects their bodily systems like metabolism and immunity. When these reptiles are kept within their optimal temperature range, they can thrive.

It is advised that you should have some knowledge about the preferred optimal temperature range of your pet reptile and maintain it on a constant high-level range in their enclosure during the day. This temperature can be decreased by approximately 10 F (-12 C) at night time.

Apart from this, the humidity level should also be controlled. One of the easiest ways to control water humidity is by placing a small plate of water or a bowl of water in their cage or enclosure to maintain humidity levels.

Are there any warm-blooded reptiles?

Almost every reptile on the earth is cold-blooded, or ectothermic. They can not alter their body temperatures and depend on the environment and temperature to regulate them. However, in 2016, scientists came across a species of lizard called the Argentinian black and white tegu lizard, which showed a little different response to changes in its surrounding temperature.

This is the first and only known species of lizard in all of the reptile kingdom which is can raise its own body temperature during the mating season. The lizard is said to raise its body temperature to 10 degrees higher than its surrounding temperature.

This phenomenon only occurs during the mating season, which is when the temperatures generally go up.

In other seasons, tegu lizards behave just like any other reptile does to maintain their body temperature. Therefore, this particular exception was pretty shocking for the scientific community when it was discovered for the first time.

Scientists are yet to discover why this particular tegu lizard is the only one who has flouted its title of a cold-blooded reptile to become something new.

Scientists theorize that this temperature rise could occur because of hormonal changes in these lizards which occur during the mating season. These hormones help to heat up their bodies when their tissues work a lot more than usual.

What is the difference between cold-blooded and warm-blooded?

In scientific terms, cold-blooded animals are called ectothermic while warm-blooded animals are called endothermic. Cold-blooded animals depend on external factors like environmental changes and temperature fluctuations to regulate their body temperature. The category of cold-blooded animals includes many amphibians, birds, and fish, and most reptiles like snakes, lizards, tortoises, and turtles.

Warm-blooded animals generate heat within their bodies through physiological systems like metabolism. This process of metabolism generates heat and energy which helps the warm-blooded animals and species function.

Their body temperature does not fluctuate according to cool or hot weather, it remains the same. The majority of the species on earth are warm-blooded, for example, all mammals and humans, as well as birds, fish, and many amphibians are warm-blooded.

A warm-blooded animal’s main source of heat is the one which is produced by their own bodies from food. This heat is used to maintain their body temperature against environmental changes and temperature changes.

When the temperature becomes too hot, warm-blooded animals tend to sweat to regulate body temperature. When the temperature is too cold, the body speeds up the process of metabolism, thereby generating more heat to keep away the cold of the atmosphere.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for are reptiles cold-blooded then why not take a look at are birds warm-blooded, or cold-blooded vs warm-blooded.

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Written by Anusuya Mukherjee

Bachelor of Arts and Law specializing in Political Science and Intellectual Property Rights

Anusuya Mukherjee picture

Anusuya MukherjeeBachelor of Arts and Law specializing in Political Science and Intellectual Property Rights

With a wealth of international experience spanning Europe, Africa, North America, and the Middle East, Anusuya brings a unique perspective to her work as a Content Assistant and Content Updating Coordinator. She holds a law degree from India and has practiced law in India and Kuwait. Anusuya is a fan of rap music and enjoys a good cup of coffee in her free time. Currently, she is working on her novel, "Mr. Ivory Merchant".

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