Specific dynamic action, apparent assimilation efficiency, and digestive rate in an arboreal pitviper, Trimeresurus stejnegeri stejnegeri

The major aims of this study were to assess the effects of temperature (15-35°C) and meal size (less than 30% snake mass) on the metabolism and digestive physiology of Trimeresurus stejnegeri stejnegeri Schmidt, 1925 and to compare the results with those of terrestrial snakes. Specific dynamic action (SDA), peak VO₂, and scope of peak VO₂ increased with meal size. Temperature had little effect on SDA. With regression analysis, we found that baseline metabolic rates of T. s. stejnegeri were generally smaller than that for frequent feeders and larger than that for infrequent feeders. We generalized three types of SDA profiles among T. s. stejnegeri and terrestrial snakes (including frequent and infrequent feeders). Trimeresurus stejnegeri stejnegeri had a more shallow and extended profile of postprandial metabolism, which did not support our hypothesis that the pace of digestive metabolism of arboreal snakes is faster than that of terrestrial snakes. The apparent assimilation efficiency (range 0.698-0.884) was significantly lower at 15°C. At the preferred temperature (26.5-28.8°C) for a postprandial 50 g snake, the simulated ratios of four parameters (time to peak VO₂, first defecation time, gastric digestion time, and final defecation time) to SDA duration approximated 0.2, 0.5-0.7, 0.7, and 1.1, respectively.