1994/01/01 by Kellar Autumn, Randi B. Weinstein, Robert J. Full · 1 citation
Agricultural and Biological Sciences · Environmental Science · #Amphibian and Reptile Biology #Animal Behavior and Reproduction #Physiological and biochemical adaptations
paper · doi:10.1086/physzool.67.1.30163845
crossref issued 1994/01/01 · crossref published 1994/01/01 · crossref published-print 1994/01/01 · openalex publication_date 1994/01/01 · crossref created 2016/01/07 · crossref deposited 2024/06/13 · openalex created_date 2025/10/10 · crossref indexed 2026/07/30 · openalex updated_date 2026/07/30
Thermal optima for physiological processes are generally high (30°-40° C) in lizards. Performance decreases substantially at low temperatures, yet some lizards are nocturnal and are active with body temperatures below 15° C. We corroborated three hypotheses about the ecophysiological consequences of the evolution of nocturnality in lizards: (1) nocturnality requires activity at low temperature; (2) activity at low temperature imposes a thermal handicap that constrains performance capacity; (3) nocturnal species have higher performance capacity at low temperature than do comparable diurnal species. Field body temperatures during activity averaged 15.3°C in Teratoscincus przewalskii, a nocturnal, terrestrial gecko from northwestern China. Individuals of T. przewalskii sustained exercise at 15° C on a treadmill for more than 60 min at 0.18 km · h⁻¹. However, 15° C was suboptimal for sustained locomotion. Resting and maximum oxygen consumption at 15° and 25° C were similar to predicted values for diurnal lizards, supporting the hypothesis that much of thermal physiology in lizards is evolutionarily conservative. The minimum cost of transport (Cmin, 0.73 mL O₂ g⁻¹ km⁻¹) for T. przewalskii was only 34% of the predicted value for a diurnal lizard of the same mass. This low cost yielded a maximum aerobic speed (MAS) of 0.27 km · h⁻¹ at 15° C, which is 2.5 times the predicted MAS for a diurnal lizard of the same mass. In comparison with predicted values for diurnal lizards, T. przewalskii showed increased but thermally submaximal locomotor performance capacity at nighttime temperatures.