The oxygen transport capacity of the cardiopulmonary system has evolved to meet the demands of simultaneously interacting elevated metabolic states (1). Consequently, scientists have become increasingly interested in the interaction of elevated metabolic states, namely digestion and activity (2). A third, less thoroughly studied physiological state capable of significantly elevating metabolism is gravidity (3). The goals of this study were to measure oxygen consumption (VO2) of gravidity, and study the interactive effects of exhaustive activity and digestion in a viviparous squamate reptile, the Checkered Garter Snake. We examined the metabolic changes during gravidity in this species by measuring oxygen consumption using flow through respirometry. We hypothesized that 1) gravidity would increase the resting metabolic rate above the resting values of non-gravid females, and 2) that this species would demonstrate an additive response to simultaneous elevated metabolic demands (both metabolic demands will be met with a sufficient supply of oxygen without affecting the performance of either state). Specifically, females would consume more oxygen during digestion, fasting exhaustive activity, and post-prandial exhaustive activity while gravid than during the non-gravid state. Current results indicate that females of this species increase resting VO2 during gravidity by a factor of 1.6 compared to the non-gravid resting state. Furthermore, compared to non-gravid females, gravid females consume significantly more oxygen during digestion (scope =1.52), but consume significantly less oxygen during fasting exhaustive activity (scope = .830). However, both gravid and non-gravid females demonstrate partial additivity of the digestive and activity responses by consuming more oxygen during post-prandial exhaustive activity (scope =1.30) than either digestion or fasting exhaustive activity alone. Current results indicate that our hypothesis for increased oxygen consumption during gravidity is supported. On the other hand, our hypothesis for an additive response to simultaneous elevated metabolic states is more complicated. This species does demonstrate an additive response to gravidity and digestion, but not to gravidity and exhaustive activity. Finally, both gravid and non-gravid females experience an additive response to digestion and exhaustive activity. Therefore, we conclude that this species is capable of demonstrating peak VO2 levels only when exhaustive activity is combined with digestion. Future studies might help explain why gravid females demonstrate higher VO2 levels during digestion, but not during exhaustive activity, by examining cardiopulmonary patterns such as ventilation and blood flow distribution patterns.