Full Moon and Dog Bite Incidents: A Brief Clinical Analysis

The potential influence of lunar phases on animal behavior, including dog bites, remain controversial.This study examined the relationship between lunar illumination and the frequency of dog and cat bite incidents.We retrospectively reviewed cases of dog or cat bites treated at a single emergency hospital in Yamagata, Japan, from January 2018 through May 2025.The lunar phase on each injury date was expressed as the illuminated fraction of the moon and grouped in 10% intervals.Scatter plots were generated to visualize the relationship between illumination and bite frequency, and cubic regression models were fitted to assess trends.A total of 48 dog bite cases and 32 cat bite cases were analyzed.Dog bite incidents increased toward higher illumination levels, with 43.8% occurring during the near-full-moon period.In contrast, cat bite incidents showed no consistent relationship with illumination.The regression model indicated a moderate positive correlation between illumination and dog bite frequency (R 2 = 0.72).These findings suggest that dog bite incidents may be modestly by lunar brightness, whereas cat bites appear unaffected.Further studies are warranted to explore behavior and environmental mechanisms underlying this association.