Reptile Thermoregulation

As ectothermic reptiles, they have a few tricks up their sleeves to keep body temperature within physiologically safe limits. For example, burrowing forms may utilise the thermal gradient of their soils, while a reptile that is entirely aquatic can take advantage of the sun’s heat rays in its habitat.


For a terrestrial lizard, panting and basking are typical thermoregulatory behaviours. Heart rate hysteresis during heating and cooling is also seen, a phenomenon that is referred to as physiological thermoregulation.

Temperature Receptors

As ectotherms, reptiles rely on temperature sensors to sense their internal and external environm 크레스티드게코 ents. These sensors, better known as thermoreceptors, relay afferent signals to the POA and activate mechanisms that manage heat dissipation in the animal. For example, the POA may send signals to activate sweating and vasodilation in order to reduce body heat or increase blood flow to the skin to cool off overheated tissues.

While a great deal is known about the thermoregulatory pathways in mammals, relatively little is understood about the reptilian thermoregulatory system. However, evidence from studies that involve local brain lesioning and heating and cooling suggests that the hypothalamus, and especially the preoptic area, is central to reptilian thermoregulation. Additionally, molecular and genetic evidence shows that a heat-sensing TRPV channel (TRPM8) is expressed in the skin of crocodiles and frogs of the genus Xenopus.

Similarly, a cold-sensing TRPM8 is expressed in the skin of a varanid lizard (Varanus varius). Together, these channels form part of a thermoregulatory system that allows reptiles to respond rapidly to environmental temperatures. Moreover, these sensory inputs must be integrated in a way that compensates for the different resistances to heat transfer within the reptilian body and between the animal and its environment. This is par 크레스티드게코 ticularly important for ectotherms, as variation in their internal set point can have a large impact on their thermal responses.

Thermoregulation During Sleep

Reptiles have a number of methods to warm themselves and cool themselves. These behaviors are designed to keep internal chemical processes within the optimal temperature range where they operate most efficiently. The sand-living reptiles, for example, heat themselves by burying in the sand and exposing only their heads. This method of thermoregulation is highly effective, especially when the sand provides an efficient surface for radiation and conduction.

As reptiles enter a sleep cycle, their metabolic activity decreases. This allows the body to conserve energy by lowering core temperatures and decreasing the rate at which heat is lost from the skin. As a result, the sleep cycle is characterized by alternating periods of light and deep sleep.

The ability to maintain a steady internal body temperature during sleep is critical for the health and functioning of many reptile species. However, just like mammals and birds, reptiles can have trouble with their natural temperature-regulating systems. This is especially true if they have a chronic health condition such as obstructive sleep apnea (snoring or gasping during sleep).

The loss of the ability to regulate body temperature in the face of uncompensable thermal loads can cause hypo- and hyperthermia, which degrade cognitive and physical performance and can even be life-threatening. For this reason, it is important to get checked for obstructive sleep apnea and to take steps to follow healthy habits that promote restful sleep.

Thermoregulation During Feeding

Like all reptiles, they are ectotherms and do not generate their own heat. They must rely on the environment to supply them with heat or they will die. This makes thermoregulation even more important for these animals. Reptiles use a variety of behaviors to warm themselves and to cool themselves in order to keep their body temperatures within an optimal range where internal chemical processes can function.

As a result, their metabolisms are very sensitive to changes in temperature. When their bodies are at their optimal temperature, they are able to digest food and perform other vital chemical functions. If the temperature goes up too high or down too low, proteins will break down and can’t be used for a number of other essential biological functions.

If a reptile is in need of raising its body temperature, it will lie in the sun or other source of radiant heat. This will activate the prostaglandins to increase the heart rate and thus move blood more rapidly, warming the blood and the body. Conversely, when it needs to decrease its body temperature, a reptile will bury itself or dive into water.

Scientists have recently discovered that apMPOA neurons with distinct thermosensory characteristics orchestrate feeding behavior in response to ambient temperatures. Those neurons send fiber projections to anorexigenic or “feeding” neurons in the PVH and ARC areas. These neurons are sex-dependent and influence both the thresholds for activation of thermoregulatory effectors and the body temperature levels and set points that regulate energy homeostasis.

Thermoregulation During Hibernation

Reptiles that live in terrestrial habitats have a variety of means of maintaining their internal body temperature at a preferred level. These mechanisms mainly include the use of solar radiation for heating and a number of ways of avoiding excessive heat loss.

Thermoregulation is also a crucial component of the physiology of hibernation in reptiles (and amphibians). Hibernation involves prolonged periods of controlled low metabolic rates and body temperatures, known as torpor, interrupted by short episodes of euthermia that require intense bouts of non-shivering thermogenesis. These episodes occur when the hibernator is awakening, preparing to feed, or during mating.

These episodes of non-shivering thermogenesis are driven by changes in the activity of brown adipose tissue (BAT). BAT metabolism is inhibited at elevated body temperatures, but the inhibition is reversed during hibernation and the resulting increase in energy expenditure appears to be responsible for the metabolic disorders associated with physiological obesity (Cohade et al., 2009).

Other aspects of reptile thermoregulation during hibernation include a reduction in overall metabolism and an increase in the rate of glycolysis to provide metabolites for a burst of energy during torpor. Hibernators also produce a fatty acid that is converted to glucose to supply a substrate for the synthesis of ATP, which is required to power BAT activity and other important physiological processes.