Reptile Thermoregulation

Using classic methods of behavioral thermoregulation, reptiles can often keep their body temperatures high and within preferred ranges. For example, the sand-living desert viper Cerastes moves in and out of burrows, adjusting its position to take advantage of available sunlight.


In laboratory experiments conducted in thermal gradient chambers, reptiles select night body temperatures that are close to environmental temperatures. However, such precision does not always mean that the reptile is thermoregulating effectively.


In order to survive in the wild, reptiles must maintain a range of body temperatures that are optimum for their internal chemical processes. When their bodies become too cold, they may have trouble breathing or digesting food. When they get too warm, they can become sluggish or sick. To avoid these problems, reptiles use a variety of behavioral mechanisms to maintain their body temperature.

Thermoregulation in reptiles occurs when their bodies become warmer or cooler in response to changes in the environment. The amount of heat produced in response to these changes is determined by the reptile’s habitat and its environmental conditions. The type of heat flow is also important. For example, a reptile in a desert will need to use different strategies to regulate its temperature than a reptile living in a temperate forest.

A reptile can also use its environment to help regulate its body temperature by basking in the sun to absorb warmth. This is a common behavior in the wild for many reptiles. Another way to regulate a reptile’s temperature is to move it to a new area of its habitat to adjust to the new environment.

Historically, one of the most reliable ways to determine whether a reptile was attempting to thermoregulate was by measuring its body temperature relative to the surrounding environmental temperature. However, a famous experiment by Heath (1964) showed that beer cans could also have their temperature raised above environmental temperatures, so this method is no longer considered to be evidence of reptiles trying to thermoregulate.


For reptiles that spend much of their time in water, thermal control is crucial. They must move to different microhabitats to keep their body temperature in the optimal range and they need to adjust to rapid environmental changes. The most common way that they achieve this is by using the sun to help regulate their body temperature. They also use the sun to absorb heat and cool off, and they can use sand or other thermal insulators as bedding.

Many reptiles, particularly amphibians and semi-aquatic reptiles such as turtles and crocodilians, are sensitive to water temperatures and turbulence. The lateral line organs of the platanna frog, Xenopus laevis, are responsive to minute variations in water temperature and turbulence. However, there is no direct link between these responses and thermoreception. The lateral line organs may instead be important in the control of movements (rheotaxis) and the sensing of water currents.

For those reptiles that do not require a high level of behavioural thermoregulation, the limiting factor is availability of water for drinking and shedding. Reptiles with limited access to water are not able to withstand elevated body temperatures. This limits the number of reptiles that can live in a given climate and restricts their geographical distribution to hot regions. This is a problem with climate change because it may affect the habitats of these reptiles and thus limit their ability to breed or move into cooler areas.


Thermoregulation in reptiles is a key issue in their ecology and physiology. It sets fundamental limits on behavioural repertoires, thermal set points and distribution patterns. In the context of chelonians it also sets limits on their survival. This paper looks at some of the ways that environmental constraints set these limits. It considers, in particular, a series of critical body temperature thresholds (ecological maximum and minimum) that restrict a reptile’s ability to escape from conditions which will ultimately lead to death.

Unlike mammals and birds, reptiles are ectothermic animals which generate little metabolic heat and depend essentially on the ambient temperature for their physiological functions. In fact, digestion cannot be carried out below a certain temperature and spermiogenesis can only occur above another. As a result, reptiles are forcibly constrained to occupy particular ecological niches by the range of environmental temperatures at which they can carry out their vital functions.

In this respect the Tuatara exemplifies the way in which environmental constraints set fundamental limits on thermoregulatory behaviour. It occupies a very limited ecological niche in a cold temperate climate. It is small in size, ovoviviparous, insectivorous and diurnal. These characteristics impose a specific mode of existence that is quite different from those of the tortoises and crocodiles which occupy a very similar ecological niche in warm climates.


Reptiles rely on the natural heat of their environment to regulate their body temperatures. This is because they’re ectothermic, meaning that they can’t generate their own internal heat through chemical processes like endothermic animals such as mammals and birds can.

Because of this, they’re completely dependent on their habitat to provide them with the right amount of warmth to keep them active and healthy. The tropical, subtropical, and temperate regions of the world are home to a huge diversity of reptile species because their environments usually have an appropriate amount of heat for them to live in.

On the other hand, reptiles that live in polar environments have to be particularly creative with their thermal strategies. For example, the saguaro lizards of the American Southwest are able to regulate their temperatures by snaking in and out of cool burrows. These burrows allow them to stay at their optimal activity temperature and avoid high energy costs.

As a result, many reptiles are able to survive even the coldest climates in the world by using their natural resources effectively. For example, in an experiment conducted by Grigoris Kapsalas and his colleagues on the Blunt-Nosed Leopard Lizard of California’s San Joaquin Desert ecosystem, they found that lizards that had access to shrubs were better able to maintain their optimum activity temperature than those without shrubs. This is because lizards that had shrubs to hide in were able to spend more of their day out of their burrows to access the warm sun.

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