Wool from sheep was one of the first fibers to be made into textiles, such
that wool was so common in ancient Babylonia (modern-day Iraq) that the name
itself of that ancient kingdom means "Land of Wool". The many many varieties
of sheep produce such a wide array of hair coverings that it's probably only
humans, among all the other creatures on the planet, with all our diversity
in color and texture of head hair, that can equal sheep in variety of pelt.
Wool is naturally flame-resistant and elastic, meaning that when dry it can
be stretched to another third of its length (two thirds when wet), and still
return to its original size when released. Wool is also hygroscopic
(absorbing water readily), such that it can absorb up to one third of its
weight in water without feeling damp. Wool in garments can absorb another 20
percent of its dry weight in water without wearers feeling damp. You'll stay
warm if your wool sweater or socks gets wet.
Wool from sheep that have been safely grazed, as in family farms, makes
wonderfully hypoallergenic stuffing for pillows, comforters, upholstery,
mattress pads, and mattresses. Organic wool, that is, wool that has been
shorn from sheep who have only eaten good clean food and have never been
subjected to nasty petrochemical sheep dips, can be a home-furnishing
godsend for people who have asthma or are who are sensitive to synthetic
materials such as foam or acrylic.
Many family farmers raise heirloom sheep breeds, doing their bit to
contribute to biodiversity and keep the sheep genepool deep and wide.