'Double-head' antlers in red deer Cervus elaphus ssp. in which the antler cores survived the death of the cortex.

An unusual case of spike antlers in male red deer is described in which the antler core apparently survived the partial mineralization of the cortex in the first rut and then in the next year supported a new, "antleroma-like" growth. On one side of the antler beam a "separation gap" developed between the living core and the dead cortex. On the opposite side a new growth of antler tissue was observed; this was made of spongious bone which in some areas partially resembled peruke-like growth and in others resembled antler "pearls". This new tissue, which developed probably in the second antler cycle, grew in the right antler from the base to the apex but in the left antler it was limited to the lower portion of the beam. This new tissue might still have been covered with velvet when the deer was shot. It is speculated that hypoandrogenism or partial lack of testosterone receptors was responsible for the survival of the antler core and the subsequent proliferation of new antler tissue in the following year.