UV Light Unmasks a Hidden Glow on Cassowary Casques

Scientists shined ultraviolet light on cassowaries and discovered that the casque on these birds glows green-blue, with southern and northern cassowaries showing strong, species-specific fluorescence patterns while dwarf cassowaries show little glow. While not yet proven as a social signal, the glow could help with species or individual recognition and offers a modern cue for studying extinct dinosaurs; the study examined 95 birds and preserved specimens, and researchers aim to test the cue’s relevance under natural rainforest light in future work.