Fig. 2. (A) Water loss ratios plotted against apnea duration for all seals. Apnea duration is a highly significant contributor to the ANCOVA model for respiratory evaporative water loss/metabolic water production (REWL/MWP; F=65, P <<0.001). (B) Metabolic rate versus apnea duration. (C) Total respiratory evaporative water loss (EW_Total) plotted against total oxygen consumption (O₂_Con). Each data point denotes a single breathing interval (apnea + recovery, or W-phase eupnea with no preceding apnea, as defined in Materials and methods), and the values for water loss and oxygen consumption are the amounts lost or consumed during that discrete interval. In the analysis, breathing intervals in which apnea duration was less than 1 min were considered W-phase breathing; an apnea duration of 0 min indicates a W-phase breathing interval in which no apnea took place.