Bighorn Sheep

Sexes usually separate in the summer after lambing and the rams rejoin the ewes and lambs in the fall for the rutting season. Spectacular head-butting competitions are characteristic for bighorn rams during the rut. Bighorns are very social and are usually found in herds, of as many as 100.

A distinctive feature of the mature male bighorn is a set of massive brown horns that spiral backwards from the top of the head, curling down around the small ears and then upwards above the nose as the animal grows older. The horns continue to grow throughout the life of the animal and, because growth slows in winter, annual rings (annuli) occur. The number of annuli shows the ram's age. An old male may have horns that complete a full circle (full curl), although the tips are often broken or "broomed" from fighting or rubbing on rocks. Horns can reach 50 in. (127 cm) from base to tip and up to 17 in. (43 cm) around the massive base. The horns of the female are much smaller, being thin and erect much like the horns of female domestic goats and only reaching 12 in. (30 cm) in length. Annuli on the ewes are closer together and it is difficult to age an animal reliably from them. The California bighorn often has a more open horn curl than the Rocky Mountain bighorn.

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