Each year, a bull grows large branching antlers that sweep up and back from the head. In May, two bumps start to swell on the animal's skull, pushing up about half an inch per day. The growing antlers are covered with a soft skin called velvet. This covering contains blood vessels which supply growth materials to the enlarging antlers. Before the autumn rutting season, the velvet dries and is shed or rubbed off.
Bulls carry their antlers into late winter or early spring.
Elk are primarily grazers, eating a variety of grasses and forbes. In winter, they paw through snow to reach grass, or turn to twigs, buds and the bark of trees. Among trees and shrubs, Pennsylvania elk seem to prefer aspen, red maple, fire cherry and blackberry. They also browse oak, striped maple, black cherry, Juneberry and witch hazel. They drink from streams and springs and, if necessary, during the winter they get water by eating snow.