Time constants of heating and cooling in the eastern water dragon, Physignathus lesueruii and some generalizations about heating and cooling in reptiles

Grigg, Gordon C.; Drane, C.R.; Courtice, Gillian P.

doi:10.1016/0306-4565(79)90052-4

Cited by 96 publications

(74 citation statements)

References 19 publications

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“…This is likely to be due to the heating and cooling regime they were exposed to, with the heating lamp generating a rapid rate of temperature rise, while cooling towards room temperature was a slow process. However, a faster rate of heating is consistent with previous studies on turtles, including Trachemys, and other species of reptiles (Bartholomew and Tucker, 1963;Spray and May, 1971;Weathers, 1971;Lucey, 1974;Voigt, 1975;Grigg et al, 1979;O'Connor, 1999;Seebacher and Franklin, 2001). …”

Section: Rates Of Heating and Coolingsupporting

confidence: 91%

“…This 'heart rate hysteresis' has been described previously in turtles (Lucey, 1974;Voigt, 1975;Smith et al, 1981) and numerous other reptiles (Bartholomew and Tucker, 1963;Grigg et al, 1979;Grigg and Seebacher, 1999;Seebacher, 2000). The higher fH values during heating were accompanied by an increased Qsys, but because systemic vascular resistance (Rsys) was reduced, blood pressure was not affected by temperature.…”

Section: Rates Of Heating and Coolingsupporting

confidence: 66%

“…This phenomenon has subsequently been documented in many other lizards (e.g. Bartholomew and Lasiewski, 1965) and reviewed by Grigg et al (1979), Seebacher (2000) and Seebacher and Grigg (2001), crocodilians (Smith, 1976;Franklin and Seebacher, 2003) and turtles (Weathers and White, 1971;Voigt, 1975). Heart rate hysteresis also occurs in free-ranging Pogona barbata (previously known as A. barbatus), and the corresponding changes in blood flow have been estimated to prolong significantly the time that body temperature remains within the preferred range (Grigg and Seebacher, 1999;Seebacher, 2000).…”

mentioning

confidence: 85%

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The cardiovascular responses of the freshwater turtleTrachemys scriptato warming and cooling

Galli

Taylor

Wang

2004

Journal of Experimental Biology

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Seven freshwater turtles Trachemys scripta were instrumented with flow probes and cannulated for blood pressure measurements. The turtles were warmed from 24 to 34°C, and cooled down to 24°C, with and without atropine. Animals exhibited a hysteresis of heart rate and blood flow to both the pulmonary and systemic circulations, which was not cholinergically mediated. Blood pressure remained constant during both warming and cooling, while systemic resistance decreased during heating and increased during cooling, indicating a barostatic response. There was a large right-to-left (R-L) shunt during warming and cooling in untreated animals, which remained relatively constant. Atropinisation resulted in a large L-R shunt, which decreased during warming and increased during cooling. Nevertheless, heating rates were the same in untreated and atropinised animals, and cooling rates were significantly longer in atropinised animals, indicating that shunt patterns contribute little to heat exchange.

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Section: Rates Of Heating and Coolingsupporting

confidence: 91%

Section: Rates Of Heating and Coolingsupporting

confidence: 66%

mentioning

confidence: 85%

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The cardiovascular responses of the freshwater turtleTrachemys scriptato warming and cooling

Galli

Taylor

Wang

2004

Journal of Experimental Biology

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“…Alternatively, the growth-rate effect might be adaptive, i.e. snakes benefit from smaller size under cool conditions because they thereby lower their thermal inertia and can heat more quickly (Grigg et al, 1979;Carrascal et al, 1992;Martín and López, 2003;Angilletta et al, 2007;Herczeg et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Thermal plasticity in young snakes: how will climate change affect the thermoregulatory tactics of ectotherms?

Aubret

Shine

2010

Journal of Experimental Biology

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SUMMARYClimate change will result in some areas becoming warmer and others cooler, and will amplify the magnitude of year-to-year thermal variation in many areas. How will such changes affect animals that rely on ambient thermal heterogeneity to behaviourally regulate their body temperatures? To explore this question, we raised 43 captive-born tiger snakes Notechis scutatus in enclosures that provided cold (19-22°C), intermediate (19-26°C) or hot (19-37°C) thermal gradients. The snakes adjusted their diel timing of thermoregulatory behaviour so effectively that when tested 14 months later, body temperatures (mean and maximum), locomotor speeds and anti-predator behaviours did not differ among treatment groups. Thus, the young snakes modified their behaviour to compensate for restricted thermal opportunities. Then, we suddenly shifted ambient conditions to mimic year-to-year variation. In contrast to the earlier plasticity, snakes failed to adjust to this change, e.g. snakes raised at cooler treatments but then shifted to hot conditions showed a higher mean body temperature for at least two months after the onset of the new thermal regime. Hence, thermal conditions experienced early in life influenced subsequent thermoregulatory tactics; the mean selected temperature of a snake depended more upon its prior raising conditions than upon its current thermoregulatory opportunities. Behavioural plasticity thus allows snakes to adjust to suboptimal thermal conditions but this plasticity is limited. The major thermoregulatory challenge from global climate change may not be the shift in mean values (to which our young snakes adjusted) but the increased year-to-year variation (with which our snakes proved less able to deal).

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“…The value of τ depended on the animal's mass and whether the animal was heating or cooling; we estimated values from equations in ref. 34. Each minute, the animal evaluated 12 locations and chose the one that brought its body temperature closest to 34°C; when multiple locations would confer the same body temperature, the closest location was chosen.…”

Section: Modeling Costs Ofmentioning

confidence: 99%

Configuration of the thermal landscape determines thermoregulatory performance of ectotherms

Sears

Angilletta

Schuler

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

230

256

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Although most organisms thermoregulate behaviorally, biologists still cannot easily predict whether mobile animals will thermoregulate in natural environments. Current models fail because they ignore how the spatial distribution of thermal resources constrains thermoregulatory performance over space and time. To overcome this limitation, we modeled the spatially explicit movements of animals constrained by access to thermal resources. Our models predict that ectotherms thermoregulate more accurately when thermal resources are dispersed throughout space than when these resources are clumped. This prediction was supported by thermoregulatory behaviors of lizards in outdoor arenas with known distributions of environmental temperatures. Further, simulations showed how the spatial structure of the landscape qualitatively affects responses of animals to climate. Biologists will need spatially explicit models to predict impacts of climate change on local scales.behavioral thermoregulation | thermal heterogeneity | thermal ecology | spatial ecology | individual-based model T he rapid warming of many environments has generated great concern about the potential impacts on biodiversity (1). Genetic changes in response to anthropogenic warming seem rare (2) or limited (3), and many species have shifted habitats over space and time (4-7). Indeed, facultative behavioral strategies are the primary means by which many species cope with changing environments (8). In a warming world, behavioral thermoregulation could enable most organisms to maintain body temperatures that promote physiological performance (9-11). However, excessive warming constrains thermoregulation, potentially leading to extinction of populations. At local scales, recent warming apparently caused numerous extinctions by limiting the duration of foraging by lizards (12). According to mechanistic models, thermal constraints on activity will play a major role in biological invasions and local extinctions (13-16). Given constraints on thermoregulatory behaviors, some have predicted that global warming could eliminate more than 40% of lizard species by 2080 (12).Such projections, although dire, underestimate the impacts of climate change by failing to consider costs of thermoregulation that are imposed by environmental heterogeneity (10,17,18). Most models assume that an animal can access either unshaded michrohabitats or shaded microhabitats without using energy to search for and move between them (14, 19). As long as the animals prefers a body temperature within the range of operative environmental temperatures, an animal can thermoregulate by shuttling between microhabitats at no cost. Given this assumption, researchers combine meteorological data and biophysical equations to calculate the expected performance of an organism in specific climates. However, thermoregulatory behaviors impose costs such as energy loss, predation risk, and missed opportunities for foraging and breeding (20), which researchers have ignored when modeling the biological impacts of clim...

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Time constants of heating and cooling in the eastern water dragon, Physignathus lesueruii and some generalizations about heating and cooling in reptiles

Cited by 96 publications

References 19 publications

The cardiovascular responses of the freshwater turtleTrachemys scriptato warming and cooling

The cardiovascular responses of the freshwater turtleTrachemys scriptato warming and cooling

Thermal plasticity in young snakes: how will climate change affect the thermoregulatory tactics of ectotherms?

Configuration of the thermal landscape determines thermoregulatory performance of ectotherms

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