Membership in this group is expanded when rams join the band during rut to mate. Ewes seek solitude in the lambing grounds to give birth, isolating their lambs for the first few weeks. Rutting season is late fall to early winter. After a six-month gestation, ewes give birth on a remote crag. Usually a single lamb is born, but sometimes twins.
Lambs have a soft, light-colored coat and small horn buds.
After a week, lambs follow the herd, staying constantly by their mother's side. Weaned at five to six months old, they nibble grasses and leaves. Yes, the U. S. Department of fish and Wildlife declared the American peninsula bighorn sheep an endangered species in 1998, primarily due to loss of habitat from urban development and from decimation of herds from viral respiratory infections that affect calves.