ive heard that rut has to do with photoperiodism sp.? which in case you dont know is basically how the length of day/night affect nature. just like leaves in the fall. it could be -30 or 110 here and the leaves change colors around the same time every year. the theory behind thisis that deer breed approximately the same time each year to give their offspring the best chance at survival. there is a website about this http://www.trmichels.com/RutDates.htmand it sounds like he knows his stuff. either way im hunting by moon phase and by his theory, one of them should be right.