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Dall
Sheep Fact Sheet
A Sheep
of a Different Color:
Dall sheep are typically all white in color, although a few black
hairs on the tail are not uncommon. The white coat is an adaptation,
or special trait that helps them survive. Dall sheep typically move
to lower altitudes in the winter, but predators are more numerous
there. The white coat helps the sheep go unseen against the snow
by predators. In the summer months, their coat does not change color,
but stays white. They are still protected, however, because they
move to steep and rocky cliffs where predators are hard-pressed
to follow.
Spiraling Outward: Both
rams (males) and ewes (females) have horns which continue to grow
throughout the animals’ lives. Horns are different from antlers
because horns are a slow-growing, permanent bone, covered by a thin
sheath of hard, bony keratin. The entire horn (core and sheath)
are never shed or “dropped” like antlers. Horns are usually
not branched, but have massive bases and taper to fine tips. Ram
horns grow continually in a spiral, but growth slows down during
winter. The annual decrease of horn growth results in a pattern
of rings along the horn called annual rings. A sheep's age can be
determined by counting these rings. Female horns are shorter, blunter,
and grow in a gentle arc over the head. They also have annual rings.
Rams frequently use their horns to fight during the breeding season.
Hoofin’ It: All
ungulates walk on hoofed toes. Hooves are made of keratin, which
encases the toe bones. Dall sheep walk on two toes which places
them in the “even-toed” group of ungulates similar to
giraffes, deer, and camels. Hooves are another adaptation that enable
Dall sheep to live on rocky, steep terrain. Their toes are flexible
and able to adjust to the uneven surfaces in their mountain habitats
where sure footing is essential.
Eating Machines: Ungulates
love to EAT! Dall sheep feed primarily on grasses and sedges. In
the winter they actually eat frozen grass, stems, lichen, and moss.
Sheep will often travel to mineral licks to eat soil. These are
typically rocky outcrops where high concentrations of minerals are
pooled. This replenishes essential minerals that the sheep cannot
get from their daily diet of plants.
Since they eat a variety
of plants, sheep have developed special adaptations for their eating
habits. They have lost their canine teeth but have developed large,
flat cheek teeth with raised ridges. When chewing, the teeth move
side-to-side and front-to-back in a triangular motion to grind food.
Strong lips and tongue are designed to grab and tear foliage and
other vegetation. Special stomach chambers allow ungulates to digest
plant material. Ruminants, such as Dall sheep, have a complex stomach
made up of four chambers. One chamber has bacteria that ferments
the food and breaks down the plant material for absorption. After
the food is fermented, the sheep regurgitates it and chews the food
again. This second chewing is called rumination. After the second
chewing, the food goes through the other three chambers and then
to the intestines. It may take FOUR days to digest a meal completely!
Super Senses: Like
other ungulates, Dall sheep have well-developed senses. Their long
noses are filled with olfactory nerves to help them detect predators.
Large ears can rotate to detect sounds from all directions. Big
eyes, set on the sides of their heads let them see in many directions
at the same time.
Loyalty and Safety: Dall
sheep have well developed social systems. Adult rams live in bands,
or groups, associated with ewe groups during the mating season.
Since Dall sheep are very loyal to their social group, they have
very specific home ranges (a geographic area where they normally
live). After joining a social group, sheep are never known to leave
it. One adaptation of living in a social group is safety from predators.
With so many eyes watching for a sign of danger, a predator can
be spotted sooner so the whole group can flee.
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