The horns, which in the wild state are
invariably well developed, and which in the cattle of our Western plains
attain very great size, have in certain breeds altogether disappeared,
and in their place there sometimes comes a remarkable crest of bony
matter which does not project beyond the skin which covers the head. If
such differences occurred in the wild state, they would be regarded as
separating the two types of animals widely from each other.

[Illustration: Egyptian Sheep]

In treating the wool-bearing animals along with beasts of burden, we
make a somewhat fanciful classification which yet is not quite without
reason. By long training man has brought these species to the state
where their covering of wool or hair, once a coating only sufficient to
afford protection from the weather, has become a very serious load. In
certain of our highly developed varieties the annual coat is so far
increased that the creature loses a large part of its bulk after the
shearer has done his work. Each year's fleece often amounts in weight
to eight to twelve pounds, and in its lifetime the animal may yield a
mass of wool far exceeding its weight of flesh and bones in any time
of its life. When the fleece is mature the animal is often burdened
with a load about as heavy in proportion to his size as is a horse by
the weight of its rider and accoutrements.

As a flesh producer, particularly in sterile fields, sheep are more
valuable than our horned cattle. They mature more rapidly, attaining
their adult size and reproducing their kind in less than two years, so
that in many parts of the world it is possible to obtain a larger
quantity of flesh from poor pasturages with sheep than with any other
of our domesticated animals. Their principal value, however, has been
from the means they afforded whereby men in high latitudes have
obtained warm clothing. Before the domestication of these creatures,
peoples who had to endure the winter of high latitudes were forced to
rely upon hides for covering--a form of clothing which is clumsy,
uncleanly, and which the chase could not supply in any considerable
quantity. Owing to its peculiar structure, the hair of the sheep makes
the strongest and warmest covering, when rendered into cloth, which has
ever been devised for the use of man. The value of this contribution is
directly related to the conditions of climate. In the intertropical
regions the sheep plays no part of importance. In high latit