The male's antlers grow as cylindrical beams projecting on each side of the head at right angles to the midline of the skull, and then fork. The lower prong of this fork may be either simple, or divided into two or three tines, with some flattening.
In the North Siberian elk (A. a. bedfordiae), the posterior division of the main fork divides into three tines, with no distinct flattening. In the common elk (A. a. alces) this branch usually expands into a broad palmation, with one large tine at the base, and a number of smaller snags on the free border. There is, however, a Scandinavian breed of the common elk in which the antlers are simpler, and recall those of the East Siberian animals.
The palmation appears to be more marked in North American moose (A. a. americanus) than in the typical Scandinavian elk.
Young female (A. a. americana) in Algonquin Park in early June
The male will drop its antlers after the mating season and conserve energy for the winter. A new set of antlers will then regrow in the spring. Antlers take three to five months to fully develop, making them one of the fastest growing animal organs. They initially have a layer of skin, called "velvet," which is shed once the antlers become fully grown. Immature bulls may not shed their antlers for the winter, but retain them until the following spring.
If a bull moose is castrated, either by accidental or chemical means, he will quickly shed his current set of antlers and then immediately begin to grow a new set of misshapen and deformed antlers that he will wear the rest of his life without ever shedding again. The distinctive looking appendages (often referred to as "devil's antlers") are the source of several myths and legends among many groups of Inuit as well as several other tribes of indigenous peoples of North America.[27]
In extremely rare circumstances a cow moose may grow antlers. This is usually attributed to a hormone imbalance.[28]