The effects of feeding and ecdysis on temperature selection by young garter snakes in a simple thermal mosaic

Abstract

Temperature selection by five young common garter snakes, Thamnophis sirtalis, was studied using a simple, two-choice thermal mosaic. The animals were housed in an arena (60 × 120 cm) within an environmental room, where they were exposed to a photoperiod of 12 h light: 12 h dark and a general ambient temperature of 20 °C. The arena contained two shelters (20 cm × 20 cm), one at ambient temperature and one heated to 30 °C. On a given day, we determined the snakes' locations in the arena twice an hour for several hours. Observations were made in this manner on most days over a period of 19 weeks. Within 1 h following a late afternoon feeding, use of the hot shelter increased from about 5–20% of observations to above 80%. Occupation of the heated shelter remained at a high level the next day and then decreased, reaching a background of 10–40% by the 3rd day after feeding. The animals displayed a higher background use when maintained on a weekly feeding regime than they did when on a biweekly regime. During a 5-day period preceding ecdysis, occupation of the hot shelter again exceeded 80% of observations; decline to a background of 0–10% began about the day of molt. Runs tests performed on the daily records of individuals indicate that hot-shelter use tended to occur in bouts. There was no suggestion of diurnal variation in thermoregulatory behavior.

Selected Body Temperature and Thermoregulatory Behavior in the Sit-and-Wait Foraging Lizard Pseudocordylus melanotus melanotus

“…In P. m. melanotus, the thermal environment may not be limiting because most lizards are active during winter, even if only for a few days in a given month. Food availability could be a limiting factor since some reptiles are known to select higher T b after eating (e.g., Beck, 1996;Brown and Griffin, 2005;Gibson et al, 1989).…”

Postprandial thermophily of Chinese green tree vipers, Trimeresurus s. stejnegeri: Interfering factors on snake temperature selection in a thigmothermal gradient

“…More attention is needed in future studies of the T p in the laboratory. Freedom of movements, presence of shelter or retreat sites, water supply, illumination (Sievert and Hutchison, 1988), and thermogradient chamber size (Gregory et al, 1982;Gibson et al, 1989) should be considered when designing the experiments.…”

“…Wagner and Gleeson, 1997;Curtin, 1998;Le Galliard et al, 2003). Only few studies tried other methods; for example, Gibson et al (1989) calculated the percentage of garter snakes, selecting hot or warm shelters.…”

Contrasted Thermal Regimes Do Not Influence Digestion and Growth Rates in a Snake from a Temperate Climate

“…It is generally assumed that the maximal T b selected by reptiles, usually expressed through a plateau following a phase of rapidly increasing T b (e.g., during basking), also corresponds to the PBT of the organism (Dawson 1975;Jobling 1981;Bennett and Beitinger 1997;Blouin-Demers et al 2000;Angilletta et al 2002). Under cool ambient temperatures, major functions such as digestion, ecdysis, foraging, mate searching, and pregnancy indeed induce a marked sunexposure thermophily (Dawson 1975;Bennett and Dawson 1976;Slip and Shine 1988;Gibson et al 1989;Gregory et al 1999;Vincent and Mori 2008). These long periods of sunbasking behaviors are essential to elevate body temperature in order to perform main major physiological functions but also for the production of vitamin D in some species and for ectoparasite control (Peterson et al 1993).…”