1. Common 30-Day Multiple in Gestation Time of Terrestrial Placentals
- Author
-
Frederick M. Brown
- Subjects
Moonlight ,Periodicity ,Physiology ,Lune ,Ecology ,Astronomy ,Placenta ,Reproduction ,Astronomical Phenomena ,Zoology ,Tapetum lucidum ,Biology ,Reflective layer ,Lunar Cycle ,Rhythm ,Species Specificity ,Pregnancy ,Physiology (medical) ,Animals ,Humans ,Pregnancy, Animal ,Gestation ,Female - Abstract
Weekly, twice-monthly, and monthly lunar related rhythms have been alleged for various animal reproductive processes. Herein gestation times of 213 types of terrestrial placental mammals were analyzed for best-fit integer multiples approximating length of any of the above lunar related rhythms. At the same time numeric controls were constituted of a completely random, a block randomized, and a sequential set of numbers spanning the data set. Among test integers 6 through 33, the number 30, approximating the 29.53-day lunar-synodic month, was consistently and statistically a best-fit multiple to the data. This might suggest a once-monthly lunar illumination, but not a twice-monthly gravitational or near-weekly tidal, influence upon animal reproduction. As for a receptor mechanism, the tapetum, or reflective layer of the retina, present in most land mammals, but absent in humans, enhances dim illumination. A suggestion is that because of this visual enhancer, cycling moonlight might be a circa-lunar physiologic timer for many terrestrial mammals.
- Published
- 1988