Of Deer, Elk and Moose Antlers

It's possible the showy antlers of male deer, elk and moose have played a more subtle role in species evolution and survival than first appears.

deer, elk and moose - painting of Irish elk
Artist's rendering of the Irish elk. Did that massive rack serve a purely practical purpose? 
C.R KNIGHT COURTESY DEPARTMENT OF LIBRARY SERVICES/AMERICAN MUSEUM OF NATURAL HISTORY