A study of the biology and ecology of Bat Cave, Grand Canyon National Park, was conducted during a series of four expeditions to the cave between 1994 and 2001. A total of 27 taxa, including 5 vertebrate and 22 macro-invertebrate species, were identified as elements of the ecology of the cave. Bat Cave is the type locality for Eschatomoxys pholeter Thomas and Pape (Coleoptera: Tenebrionidae) and an undescribed genus of tineid moth, both of which were discovered during this study. Bat Cave has the most species-rich macro-invertebrate ecology currently known in a cave in the park