Most herds of elk are led by an older cow elk with the bull herding the group. A large bull elk will herd together several cow elk for mating. The smaller bulls will be run off by the older male, who can be quite aggressive and dangerous while in rut. They have been known to tear down deer fences and even kill other animals with their fighting. The smaller bulls will herd together and attempt to breed the cows from time to time.
Breeding starts at the first sign of cold weather.
The gestation period is nine months. Single births are most common, but occasionally twin births do occur. The newborns are up and running soon after birth. The spots seen on the coats of the very young elk are shed by about three months of age. Antlers are the bony growths on the foreheads of most male deer.