Mating occurs during November and December. During the breeding season, rams can become very aggressive and in a 60-day breeding season, one ram is able to mate with up to 35 female ewes—although, most males are not able to do so until they are 7 years old due to the tough competition.
At the beginning of the nineteenth century, there were between 1.5 million to two million bighorn sheep in North America. Today, there are less than 70,000.
Wild sheep live in social groups, but rams and ewes typically meet only to mate. Rams live in bachelor groups and females live in herds with other females and their young rams. When fall mating arrives, rams gather in larger groups and ram fighting escalates. Usually only stronger, older rams (with bigger horns) are able to mate.
Bighorn sheep were once widespread throughout western North America. By the 1920’s, bighorn sheep were eliminated from Washington, Oregon, Texas, North Dakota, South Dakota, Nebraska, and part of Mexico. Today, populations have been re-established through transplanting sheep from healthy populations into vacant places.