Ruminants.—Animals which, like the sheep, oxen, goats, deer, etc., ruminate or chew the cud in this manner, are called ruminants. In all ruminants the weight of the body is supported by the tips of the third and fourth toes of the feet, the remaining toes either having completely disappeared or remaining very small ([Fig. 176]). The tips of the toes are encased in horny hoofs, which represent greatly enlarged claws or nails. The ruminants therefore belong to what may be called the even-toed hoofed mammals. Pigs are also even-toed hoofed mammals, but they are not ruminants, because, having simple stomachs, they do not chew the cud.
Fig. 176.—Bones of fore-foot of Red Deer. Fig. 177.—Bones of fore-foot of Horse.
(After Flower.) (After Flower.)
Other hoofed mammals.—In the horse and donkey the reduction of the number of toes has gone still further; for these animals have now only the third or middle toe of each foot left ([Fig. 177]); and because it has to carry the whole weight of the body, it has become very large and stout; its tip is encased in a hoof.
The hoofed mammals are therefore divided into two groups:
(1) the odd-toed, including the horse and ass (they have simple stomachs, and therefore do not chew the cud); and
(2) the even-toed, including (a) ruminants like the sheep, etc., and (b) such non-ruminants as the pigs and their relatives.
The inherited habits of the sheep.—As in the cases of the dog and cat, so in the sheep, the true explanation of several curious habits is to be found in the manner of life of the wild ancestors; for it must be remembered that domestication, however kindly an animal may take to it, is an artificial condition of life. Wild sheep live in flocks, as a rule in cold and mountainous districts; and some organisation is necessary if they are not to be at the mercy of savage carnivores. An old and experienced ram is generally in charge of the flock, and in case of alarm he leads the way to a more inaccessible position. The rest of the flock follow in single file, closely imitating his every movement, leaping without hesitation—and therefore saving valuable time—wherever he has leapt. The survival of this instinct in domestic sheep may be observed whenever a flock is travelling along the road. Even young lambs still display a decided preference for rocks, hillocks, and other elevated positions. Wild sheep, being so liable to sudden interruption when grazing, are enabled by their compound stomachs to swallow food quickly and postpone the chewing process to a more favourable opportunity. Sentinels usually keep watch, and warn the flock of approaching enemies by stamping their hoofs on the ground, an action which may still be seen whenever a ewe fears danger to her lambs.
The play and education of the young.—The young of mammals are usually under the care of the mother for education and protection until they are nearly adult; and it is generally found that the longest infancy (in proportion to the natural life of the animal) occurs in the most intelligent races. The importance of the play and education period is very great, for it not only gives the young animal an opportunity of training its natural faculties in comparative safety, by exercise of various kinds and by games with companions of its own age and strength; but it allows the mother to impart, by direct instruction, some of the experience which she has personally gained during her life. The extent of this maternal education is greater than has been generally supposed; and every opportunity should be taken of observing and recording cases of it.[15]