Sheep arrive with their houses on their back. This is due to wool characteristics that also serve to make it the most unique, completely natural and multipurpose fiber available.
Sheep wool has the capability to keep the body at at even temperature because it does not trap heat. It insulates versus trapping heat. This means that in hot weather it keeps the animal (or you) cool and in cold weather it keeps them (or you) warm.
Wool clothing does not cling to the skin like rayons or nylons and even cottons do. This allows for air circulation next to your skin and is part of the insulation properties and comfort of wearing wool.
Readily absorbs water and can also release it. Again it does not trap. For sheep this prevents moisture from being held at the skin. It prevents the clammy, cold feeling you may experience when wearing some types of synthetic clothing and sweating. Because of this feature it also dries out slowly.
Naturally fire resistant meaning it does not readily burn. This feature is what makes wool attractive as an insulating material in homes.
Strands of wool are crimped (imagine your hair crimped with a crimping iron - wool does that naturally). Due to having crimp wool has the ability to stretch and then return to it's natural length. This elasticity is a very promising feature that we can not achieve with any other synthetic material. It is what makes the fiber strong and durable.
Felting is the nature of most animal fur that allows it to entangle and form mats of fabric. The fibers (strands) can interlock with each other due to ridges on the individual fibers. Sheep wool is highly regarded for its ability to felt and form fabrics that are near impossible to tear.
Felting is the wool characteristic that causes your wool sweater to shrink each time you wash it in warm or hot soapy water and subject it to to rough treatment (ie the washing machine).
Sheep wool is very strong and durable partly due to it's felting feature. The fibers are strong and will hold together through much twisting and turning, much like a lock of hair. This feature is what creates such long lasting garments.
The fibers readily accept dye colors. The natural off-white raw color is highly preferred due to its ability to take on color with ease. The product can be easily dyed with natural flower dyes. In contrast synthetic fibers are not dyed easily and will require harsher chemical dyes to change their color.