Observations of a greater sac-winged bat pup (Saccopteryx bilineata) with a chromatic disorder

Chromatic disorders in bats are typically documented by brief, incidental observations of individuals at day roosts or by accidental captures during mist-netting. Such descriptions usually lack observations on social behaviour including interactions between bats with aberrant pigmentation and other individuals. Here, we report the first observation of leucism in the greater sac-winged bat Saccopteryx bilineata. Over the course of six weeks, we were able to follow the development of a wild pup with a conspicuous aberrant pigmentation, by observing it in its day roost. Our observations indicate that the vocal and behavioural development of the pup was entirely normal, as well as the integration into its social group. After six weeks, when the pup was already foraging individually, it did not return to its colony in the morning, indicating that it may have been preyed on.