Foster and Kreitzman - Seasons of Life - Sheep
Type of Spiritual Experience
A description of the experience
Seasons of Life – Russell G Foster and Leon Kreitzman
If sheep are isolated from changes in environmental photoperiod and artificially maintained under a constant daily 12 hour light and 12 hour dark L:D cycle with no change in day-length, they will still show a circannual cycle in reproduction. This suggests that although there is a circadian based photoperiod timer there is also a separate circannual timer….