Blog Photography Articles
Dall Sheep (Ovis dalli dalli)
Dall Sheep inhabit the mountain ranges of Alaska. Dall sheep are found in relatively dry country and frequent a special combination of open alpine ridges, meadows, and steep slopes with extremely rugged "escape terrain" in the immediate vicinity.They use the ridges, meadows, and steep slopes for feeding and resting. When danger approaches they flee to the rocks and crags to elude pursuers. They are generally high country animals but sometimes occur in rocky gorges below timberline in Alaska.
Male Dall sheep are called rams. They are distinguished by massive curling horns. The females, called ewes, have shorter, more slender, slightly curved horns. Most generally, a 12-year-old sheep is considered very old. As rams mature, their horns form a circle when seen from the side. Ram horns reach half a circle in about two or three years, three-quarters of a circle in four to five years, and a full circle or "curl" in seven to eight years.
The young, called lambs, are born in late May or early June. As lambing approaches, ewes seek solitude and protection from predators in the most rugged cliffs available on their spring ranges. Ewes bear a single lamb, and the ewe-lamb pairs remain in the lambing cliffs a few days until the lambs are strong enough to travel. Lambs begin feeding on vegetation within a week after birth and are usually weaned by October.
Normally, ewes have their first lamb at age 3 and produce a lamb annually. Sheep have well-developed social systems. Adult rams live in bands which seldom associate with ewe groups except during the mating season in late November and early December.
The horn clashing for which rams are so well known does not result from fights over possession of ewes, but is a means of establishing order. These clashes occur throughout the year (among females, as well) on an occasional basis. They occur more frequently just before the rut when rams are moving among the ewes and meet unfamiliar rams of similar horn size. Dall rams can sire offspring at 18 months of age, but normally they do not breed successfully until they approach dominance rank (at full curl age and size).
The diets of Dall sheep vary from range to range. During summer, food is abundant, and a wide variety of plants is consumed. Winter diet is much more limited and consists primarily of dry, frozen grass and sedge stems available when snow is blown off the winter ranges. Some populations use significant amounts of lichen and moss during winter.
Many Dall sheep populations visit mineral licks during the spring and often travel many miles to eat the soil at these unusual geological formations. As several different bands of sheep meet at mineral licks, ram and ewe groups may mingle and young rams join the ram band which happens to be present at the time. This random contribution of young rams to different ram bands may benefit sheep by maintaining genetic diversity.Sheep are very loyal to their home ranges. Mineral licks are good spots to observe sheep because the animals are so intent on eating the dirt they pay little attention to humans. However, major disturbances such as low-flying aircraft or operating machinery readily drive sheep from the mineral licks. Photography of Dall sheep is popular for many visitors and residents of Alaska and is not limited by season.
Text from the State of Alaska Fish and Game Wildlife Notebook Series (used with permission)
Text: Wayne E. Heimer
Dall sheep inhabit the subarctic mountain ranges of Alaska, and are often confused with Mountain goats which inhabit Alaska's coastal mountain ranges. © Patrick J. Endres
Male Dall Sheep have thick curling horns. The females have shorter, more slender, slightly curved horns. © Patrick J. Endres
Lambs are born in May. © Patrick J. Endres
Dall sheep ewe and lamb in falling snow, Atigun Canyon, Brooks range, Alaska. © Patrick J. Endres
During the summer when food is abundant, the sheep eat a wide variety of plants. © Patrick J. Endres
Males live in bands which seldom associate with female groups except during the mating season in late November and early December. © Patrick J. Endres
Dall sheep prefer habit with rugged ground in order to escape from predators that cannot travel quickly through such terrain. © Patrick J. Endres