Female and male P. pustulosus display optomotor responses to a rotating black-and-white striped drum, both under low-light conditions in the laboratory and outdoors under a range of natural, nocturnal conditions. Physalaemus pustulosus also display optomotor responses under these conditions when the colours of the drum are filtered to mimic the reflectance spectrum of the male’s inflated vocal sac (M. Cummings, X. Bernal, C. Jennings, A. S. Rand & M. J. Ryan, unpublished data). These results indicate that the visual system of P. pustulosus can detect the vocal sac under the range of conditions in which males call in nature.