Abstract: Bats in North America have been dying off due to the invasion of a fungal disease (White Nose Syndrome). In this talk, I’ll present a very simple linear algebraic model to predict the magnitude of the die-offs. By comparing these models to some data about actual bat survival, my collaborator and I also hypothesized that the disease might be causing rapid evolution in the bat populations and this could give some populations better hope of surviving. I’ll go through these models and show how the predictions they make are different from models that don’t include bat evolution. I’ll also talk a little about some of the intervention strategies that have been proposed to help bat populations survive, and use these models to show how some of them might accidentally hurt rather than help, if we don’t figure out whether the main impacts of disease are evolutionary or immunological first.