Distributions of Conception and Parturition in Dogs According to the Lunar Phase

The possible effects of the Moon and its phases on parturition timing have been extensively reported in the literature in both human and animal species, sometimes finding a causal relationship and other times denying any possible influence. However, knowing parturition timing is pivotal to guarantee the best assistance to mothers and newborns, especially in polytocous species like dogs. Seventy-eight matings and related parturitions of three different canine breeds (Dobermann, Golden Retriever, and Samoyed dogs) were analyzed. Both matings and parturitions occurred more frequently in certain lunar phases, with matings mainly occurring during the Waning Moon and parturitions during the New Moon. Moreover, multiparous bitches mated more frequently during the New Moon, while primiparous ones did so during the Waxing Moon. Parturition occurred more frequently during the Waxing Moon in primiparous bitches and during the Waning Moon in multiparous ones. However, multiparous bitches bearing smaller litters experienced longer gestational lengths and more frequent parturitions during the Waxing Moon. Primiparous bitches bearing larger litters showed more frequent parturitions during the Waning Moon, with shorter gestational lengths. The results suggest that, among other factors influencing the timing of delivery, parturition in dogs can occur more frequently in certain lunar phases.