ABSTRACT
Because most desert-dwelling lizards rely primarily on behavioral thermoregulation for the maintenance of active body temperature, the effectiveness of panting as a thermoregulatory mechanism for evaporative cooling has not been widely explored. We measured changes in body temperature (Tb) with increasing air temperature (Ta) for 17 species of lizards that range across New Mexico and Arizona and quantified the temperatures associated with the onset of panting, and the capacity of individuals to depress Tb below Ta while panting, and estimated the critical thermal maxima (CTmax) for each individual. We examined these variables as a function of phylogeny, body mass and local acclimatization temperature. We found that many species can depress Tb 2–3°C below Ta while panting, and the capacity to do so appears to be a function of each species' ecology and thermal environment, rather than phylogeny. Panting thresholds and CTmax values are phylogenetically conserved within groups. Understanding the functional significance of panting and its potential importance as a thermoregulatory mechanism will improve our understanding of the potential for species' persistence in an increasingly warmer world.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: C.L.L., B.O.W.; Methodology: C.L.L., B.O.W.; Formal analysis: C.L.L.; Investigation: C.L.L.; Resources: B.O.W.; Data curation: C.L.L.; Writing - original draft: C.L.L.; Writing - review & editing: C.L.L., B.O.W.; Visualization: C.L.L.; Supervision: B.O.W.; Funding acquisition: C.L.L., B.O.W.
Funding
Funding to C.L.L. was provided by the University of New Mexico BGSA Research Allocations Committee, the University of New Mexico GPSA Student Research Grant and New Mexico Research Grant, the Melinda Bealmer Memorial Scholarship, and the Alvin R. and Caroline G. Grove Summer Research Scholarship. This work was also supported by National Science Foundation grant DEB 1457524 to B.O.W. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
- Received February 25, 2020.
- Accepted July 29, 2020.
- © 2020. Published by The Company of Biologists Ltd
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