Lunar Phobia in Temperate Vespertilionid Bats: Modeling Moonlight’s Impact on Bat Activity

Indianapolis, IN

Lunar cycles have long been associated with changes in animal behavior. Previous studies concerning bat behavior in response to lunar cycle have described lunar phobia tendencies. We examined how lunar cycle influences three bat species within the Myotis genus and assessed if lunar phobia explains their behavior. Study sites included three sites in Indiana; two in Illinois; and one in Kentucky. Within the five study sites, a total of fifty bats were captured and fitted with transmitters. Receivers were placed within the roosting sites and recorded data on bat activity during nighttime hours. Moon phase, (moon) percent illumination, moonrise / moonset times, and cloud cover data were converted into numerical forms and factored into a model to estimate the relative amount of moonlight received each night. Results suggest that bat foraging time was significantly influenced by moonlight level, while number of bats captured each night showed no such relationship. North American Myotis bats may have a preference for foraging during nights where the moon is brighter and has more of a presence. Instances of lunar phobia in bats are likely the result of regional differences in preferred prey and influential predator species.