Primates Shed Light on Glowing Mammals – Adaptation or Epiphenomenon?

Fluorescence is the ability of chemicals and materials to give off visible or invisible light after absorbing radiation such as ultraviolet light. Fluorescence has been documented in several mammalian families, yet Primates, as an order, have received limited attention in this regard. Within Primates, the suborder Strepsirrhini has been particularly overlooked. Strepsirrhines are compelling subjects due to their retention of primitive mammalian characteristics, representing a significant knowledge gap with respect to the occurrence of fluorescing pelage within the class Mammalia. To address this gap, we investigated the presence and absence of fluorescence in the pelage of preserved museum strepsirrhine specimens housed at the American Museum of Natural History (New York, NY). Ultraviolet light was used to illuminate the pelage of 48 individuals (n=26 species) and the presence or absence of fluorescence was recorded across several body regions. The results were additionally documented using digital photography. Descriptive and inferential statistics were performed to test the hypothesis that ecological traits (activity pattern, substrate use, and diet) are related to the presence or absence of fluorescence. These data are used in conjunction with a larger mammalian data set from Travouillon et al. (2023), allowing us to address crucial deficiencies in the scientific community's understanding of the phenomenon of “glowing mammals”. Moreover, with a more comprehensive dataset, we can explore broader evolutionary questions, such as whether fluorescence in primates serves an adaptive function or is merely a byproduct of hair chemistry.