Selenophobia (moonlight avoidance) in nocturnal rodents: A primer

Photophobia, aversion for brightly lit environments, is commonly observed in laboratory nocturnal rodents such as mice and rats, as indicated, for example, by the light-dark box test. The universality of photophobia in laboratory nocturnal rodents rises questions on its corresponding behavior in nature and on what adaptive value may have led to the selection of this behavior during biological evolution. Nocturnality alone is insufficient to explain photophobic behavior, as nocturnal rodents show reduced roaming in the day just because they are sleeping and not because they are choosing to avoid a possibly aversive daylight. On the other hand, a natural behavior more directly related to the photophobia observed in the laboratory is selenophobia (moonlight avoidance), which in free-ranging rodents can be operatively defined as the reduction of exploratory and foraging activities in moonlit nights compared with dark nights. In the case of selenophobia, factors related to nocturnality are ruled out, and light-related factors can be easily isolated. Selenophobia has been found in a wide variety of nocturnal rodents, for which it may represent an antipredatory adaptation. A technology-aided study of selenophobia may strongly contribute to a better understanding of its nature, of the relative contributions of instinct and learning to this behavior, and of its neural underpinnings. In particular, new behavioral and neurophysiological technologies, for example, miniaturized radiocollars, freely accessible testing chambers equipped with infrared video cameras, animal-borne miniaturized video cameras, and noninvasive electrophysiological recordings, may be of particular usefulness to shed light on selenophobia. (PsycInfo Database Record (c) 2025 APA, all rights reserved).