The moon has long intrigued humanity. Cultures throughout the world have myths and beliefs concerning the moon, many of which ascribe mystical significance to Earth’s natural satellite. Some beliefs hold that the full moon drives individuals to insanity, while other common moon myths contend that the full moon imbues fertility and causes women to give birth. While this has last belief long been disregarded as an old wives’ tale, new research has shown that there might be some credence to this myth – at least in the animal kingdom.

According to research recently published in PLOS One, the full moon is responsible for a significant spike in cow births each lunar cycle. The study, appropriately titled “Lunar Cycle Influences Spontaneous Delivery in Cows,” was conducted by biologists at the University of Tokyo who studied over 400 Holstein Friesian dairy cows. This specific breed of cow was chosen for its low level of genetic diversity, which would allow researchers to isolate as many variables as possible and determine if indeed the full moon causes a spike in births.

Records of the cows’ births were examined throughout a three-year period, and researchers discovered a statistically conclusive spike in births around the full moon. The effect of the moon was found to be even more consistent among cows who had previously delivered calves.

While the team has conclusively found the moon’s effect on cow births, the reasons behind it are still unknown, and their research has yet to extend to human subjects. In a University of Tokyo press release, lead researcher Tomohiro Yonezawa states his team is hopeful that this research might one day shine a light on the mystery of the moon’s effect on human births:

[…] our findings do not immediately hold true for human births and we still don’t know why the number of calves delivered increases around the full moon. However, we are excited to do further research because the findings should eventually lead to discoveries that can be generalized to human births.

The lunar cycle has profound effects on the natural world, including tidal patterns and the migratory patterns of many animals. It’s natural then, that we could conclude that humans would be affected as well. Research like this cow study might one day prove just how interconnected we and the celestial bodies truly are.