Dall Sheep Information
(Ovis dalli dalli)
Order: Artiodactyla (even-toed hooved animals)
Family: Bovidae (cattle, goats, and sheep)
Body: The Dall sheep is the only all white non-domesticated sheep in the world. Mountain sheep, in general, are characterized by their massive horns and both males (rams) and females (ewes) grow them. The ewe's horns are shorter, more slender, and less curved than the rams. Their horns grow most of the year but do slow to a halt during the winter. This cessation in horn growth leaves fairly distinctive rings or annuli on the horns and allow the age of the sheep to be accurately determined. By the age of 3, it is easy to distinguish rams from ewes by looking at their horns. By 3 years of age a ram will have about a half a curl, reach a three quarter curl by 4 to 5 years, and but the age of 7, they will usually achieve a full curl. Unlike many animals, sheep horns are never shed.
A mature ram will stand about around 3 feet at the shoulder and weigh up to 300 pounds, while ewes are usually 2.5 feet at the shoulder and weigh around 150 pounds. Their white hair is rather coarse and can be 3 inches long in the winter. During the spring, the sheep will rub off their heavy coats on rocks or tree branches. This rubbing off of hair often accounts for the darker stains on their coats.
Diet: Dall sheep tend to vary their diet in response to weather conditions. The lush vegetation of the spring and summer allows the sheep to consume a varied diet of rich plant life. During the harsh winters, the sheep must rely on dry grasses, sedges, lichens, and moss on windblown ridges or dug up from underneath thin snow. Years with heavy snowfall or when the snow developes a hard crust, many sheep starve to death. The animals may gather in large numbers at natural mineral licks as well.
Range: Dall sheep are found in remote, rugged areas of the mountains of Alaska, they Yukon and Northwest Territories i n Canada, and in a few areas in British Columbia. They do not inhabit the Southeast areas of Alaska however. They prefer rugged ridges and scree slopes that have easy access to escape routes. These steep, jagged cliffs and slopes are used to escape from predators that are not as sure footed. Rams and ewes can often be seen resting on steep slopes into which they dig out small ledges in order to have better areas to rest.
Life History: Dall sheep mate in late November and early December during their rut. The horn clashing that occurs between rams of similar horn sizes, occures throughout the year, but does tend to increase during rut. Ewes will challenge each other with horn clashes as well. Most of these clashes are not the incredible, violent clashes seen on TV documentaries, but are usually more subdued with wrestling and pushing. That said, it is not uncommon to see rams with eye injuries due to horn clashes. They clash to establish rank in their highly developed social system, not really for possession of a ewe, however the ram with the higher ranking will generally get first choice of a mate.
The ewe will give birth to a single lamb in late May or early June of the following year. As lambing time nears, the ewes seek out the most isolated and rugged areas in their range to give birth. The lambs are born after an average gestation period of 180 and weigh 5 to 6 pounds. The ewes and lambs generally stay together in nursery herds, while the rams stay in small groups of their own. The only time that they mingle is during the rut season. Lambs have a fairly low survival rate due to the harsh environment they live in and due to predators such as wolves, coyotes, and eagles. Falls and starvation are two major environmental factors. Recreational hunting of Dall sheep is limited to full curl rams during August and September, however subsistence hunting is not limited to the age or sex of the sheep taken. Dall sheep are also very susceptible to disease introduced by domesticated sheep or cattle, which may graze near their ranges. If a sheep reaches the age of twelve, it is considered very old, with an occassional sheep reaching sixteen to nineteen years old.
Dall's sheep were named for the scientist William H. Dall, of Dall's porpoise fame, however he likely had no direct involvement with their discovery. Denali National Park was originally designated to protect the habitat of the Dall sheep and to protect them from human hunting, as they are not overly weary humans.
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