Values of body mass (BM) and total body water as percentage of body mass (TBW % BM) were used to estimate net fat energy use over 67 d for individual little brown bats (Myotis lucifugus) experimentally infected with Pseudogymnoascus destructans and negative control (non-infected) bats. Values in the table are mean (SD) and n = sample size. Initial TBW % BM was significantly different between treatment groups. Over the course of the experiment, infected bats demonstrated a significant increase in TBW % BM and used significantly more fat energy than non-infected bats. Body mass decreased significantly over the experiment in infected and control bats but there was no difference between groups.