With adults, they found that the median breeding date, or the peak of the rut, to be November 20. Yearlings weren’t far behind at November 26, but the fawns came in at either December 16 or December 20—a full 30 days later than adult does. Yet some of the yearlings were breed as late as December 22, while some adults stretched it out to January 8—these were outliers, isolated examples that deviated from the norm, but worth noting. The study also found that yearlings in the north bred 14 days later than yearlings in south—December 6 versus November 22. Geography, terrain, and big open country altered conception by two full weeks.