<strong>The influence of circadian rhythms on the metabolism of the snake <em>Bothrops jararaca</em> (Serpentes, Viperidae)</strong> - DOI: 10.4025/actascibiolsci.v30i3.5030

Abstract

The thermoregulatory activity has led to an extensive search for correlations between physiological variables, including metabolic functions, and the ideal level of body temperature. Snakes were also often seen basking, when their body temperatures were relatively independent of ambient temperature, indicating successful thermoregulation. Bothrops jararaca were exposed to two different ambient temperatures (20 and 30ºC) over a time course of three weeks and oxygen consumption and body temperature were measured. The snakes exhibited a freerunning rhythm of body temperature. Metabolic rate was increased at the same circadian phase as the increase in body temperature in the 30ºC. The increase of body temperature and oxygen consumption of B. jararaca occurs in the scotophase of the photoperiod, consistent with that of nocturnal species. However, prior to a scotophase period the snakes under 20ºC maintain body temperature and oxygen consumption at higher levels during the day. These results demonstrate for the first time that ectothermic animals may display physiologically generated circadian rhythms of body temperature similar to those recorded in endotherms. Circadian rhythms allow animals to anticipate environmental changes: physiological parameters such as body temperature and mobilization of energy reserves have to be adjusted before the expected environmental changes actually take place.