The flexible shell of some oviparous reptiles has led to differences in nutrient mobilization and water relations when compared to their rigid-shelled counterparts. Flexible-shelled eggs gain more water during development, and because of the shell structure, yolk calcium content is higher than that of eggshells. When water availability is altered for reptiles with flexible-shelled eggs, differences in both energy and nutrient utilization are observed. This study was designed to determine the baseline metabolic rate during development for the snake, Pantherophis guttatus under normal conditions, and to observe how changes in eggshell calcium and water availability impact embryonic oxygen consumption. Eggshell calcium was decreased while water uptake was increased by removing the outer calcareous eggshell layer from some eggs. When eggs are left intact, an exponential increase in oxygen consumption is observed, supporting previous studies, while removal of the eggshell produces no effect on metabolism.