Physiological mechanisms of thermoregulation in reptiles: a review

Abstract

Biological functions are dependent on the temperature of the organism. Animals may respond to fluctuation in the thermal environment by regulating their body temperature and by modifying physiological and biochemical rates. Phenotypic flexibility (reversible phenotypic plasticity, acclimation, or acclimatisation in rate functions occurs in all major taxonomic groups and may be considered as an ancestral condition. Within the Reptilia, representatives from all major groups show phenotypic flexibility in response to long-term or chronic changes in the thermal environment. Acclimation or acclimatisation in reptiles are most commonly assessed by measuring whole animal responses such as oxygen consumption, but whole animal responses are comprised of variation in individual traits such as enzyme activities, hormone expression, and cardiovascular functions. The challenge now lies in connecting the changes in the components to the functioning of the whole animal and its fitness. Experimental designs in research on reptilian thermal physiology should incorporate the capacity for reversible phenotypic plasticity as a null-hypothesis, because the significance of differential body temperature-performance relationships (thermal reaction norms) between individuals, populations, or species cannot be assessed without testing that null-hypothesis.

Effects of feeding on thermoregulatory behaviours and gut blood flow in white sturgeon (Acipenser transmontanus) using biotelemetry in combination with standard techniques

“…Thermoregulation in ectotherms is shown to be extremely complex, and numerous reviews have discussed the potential costs and benefits associated with these behaviours (Huey and Slatkin, 1976;Reynolds and Casterlin, 1979;Seebacher, 2005;Seebacher and Franklin, 2005;Golovanov, 2006). It is generally believed that ectothermic animals can benefit from behavioural thermoregulation by avoiding harmful temperatures and by getting some control over metabolic processes, but these behaviours are associated with costs, which in some situations outweigh the benefits making thermoregulation impractical.…”

“…Most studies on thermoregulatory behaviour have been conducted on reptiles and show that most species will regulate their body temperature when given the opportunity (Bogert, 1949;Seebacher and Franklin, 2005). Thermoregulation in ectotherms is believed to be most pronounced in land-living species where the thermoregulatory behaviour to a large extent involves basking in, or avoiding, the sun.…”

Warm and Cold-Bloodedness in a Newer Perspective

“…Little else is said about what viable transitions in this evolutionary conversion could have taken place and to convert a cold blooded animal into a warm blooded animal is like converting a model t-ford into Lexus etc. Now coming to the present article and how the author views this fascinating journey of evolution of endotherm or warm-bloodedness with side by side discussing the differences between the warm blooded and cold blooded animals (they are strictly not cold blooded as they also have some thermoregulatory mechanisms [2] and should more appropriately be called as less warm blooded).…”

Critical Body Temperature Profile as Indicator of Heat Stress Vulnerability

“…Epidemiological and experimental researches [13][14][15] elucidate the challenges of thermoregulation of people in extreme hot environment 16) . Essentially, the scheme of thermoregulation to prevent body core temperature (T cr ) from rising into a hyperthermic range is approximated by dual inputs, as one side of the gradient for heat transfer from the body core to shell 17) , as well as the independent cutaneous reflex drive for adjustment of skin blood flow 18) . In the context of the direct relationship of extreme hot environment to increased mortality and morbidity, this study analyses the heat stress vulnerability with respect to body temperature profiling due to environmental warmth, in order to educating people of the approaches to mitigate heat injury.…”