The gestation period is between 249 and 262 days. The life span of elk is 14 to 16 years for males and 15 to 17 for females, though in 1937 a tagged elk in Arizona was 25 when it was harvested. The antlers are smooth and get very large, averaging more than 4 ft each in length. Antler development is a function of age. The antler cast occurs in January to March for adult bulls and from March through May for sub-adults.
New growth occurs shortly after the cast.
The growing period ranges from 90 days for yearlings to 150 days for adult bulls. Therefore it's possible to see yearlings with old spikes at the same time as bulls with a foot of velvet. By early August, antler growth is complete. The velvet dries up and the antlers harden. The velvet is stripped off in a matter of hours and the elk polishes its antlers against trees.