THE NATURAL HISTORY OF THE HORSE

It is a curious phase of the history of the horse in this country that the ancestors of the horse once lived in this country in large numbers, and then entirely disappeared. The ancestry of the horse has been traced back some three millions of years, and through that period practically every step of change, from the little five-toed whippetlike animal, to the Percheron or thoroughbred of to-day, can be illustrated by actual fossil remains.

The most complete collection of fossil remains of the horse, and the best illustrations of the different phases of his development, anywhere in the world, are in our Museum of Natural History in New York.

When the remains of the prehistoric horse were first discovered, so little was known on the subject, that the great naturalist, Richard Owen, called him the Hyracotherium or "Hyrax-like Beast," referring to the coney of Scripture, little suspecting that there had been discovered in this Hyracotherium the fossil remains of the horse of millions of years ago. In the Jardin d'Acclimatation in Paris there are two little horses at the present time each measuring under 24 inches at the withers.

This little animal was first provided with the flat, spreading, five-toed foot suitable to the low-lying and marshy land in which he lived. His teeth and mouth, and shorter neck and jaw, were adapted to the softer and more luxuriant herbage of that time and place.

As the water left the earth, this little animal gradually adapted himself to the harder ground, the less luxuriant vegetable growth and the necessities of the situation, which required that he should travel farther for his nourishment, and that he should travel faster, to escape his enemies.

Pounding along on the plateaux, which became his natural habitat, he lost one toe after another, first from his hind feet, because they do the most work in propelling him, and then from his front feet. His neck and jaw grew longer as he was obliged to reach lower and lower down to bite off the wiry grasses of the plain.

In short, the horse's foot and leg are developed from the short, slender leg and cushioned foot of, say, something resembling the foot and leg of a delicate-limbed tapir to its present form.

Compared with a man's hand, for example, the horse's knee is represented by the human wrist; the hairless spot of skin with its cushion beneath—fatty cushion of the fetlock—represents the prominence behind the root of each finger opposite the knuckles; and the hoof itself represents the nail of the middle finger of man.

299a

Intermediate stage in development of the horse, being about three feet high, and having three complete toes

299b

Showing long crowns of teeth

There are other patches of callous skin, sometimes called "chestnuts" or "mallenders," which appear; that on the fore leg is above the wrist joint or "knee," that on the hind leg below the ankle or "hock" joint. These, however, are still puzzles to the scientists, although in an old book on the horse, by Youatt, he speaks of them as diseases and prescribes remedies for their cure.

Huxley maintained that the theory of evolution pointed to the five-toed horse, and he stoutly insisted that the fossil remains of such an animal would some day be discovered, and sure enough we now have in New York City the fossil remains of these prehistoric horses, carrying out, even in minute detail, the steps of development he had outlined. There is the horse with four toes (Plate I.), then the horse with these toes grown shorter, until they hang above the ground, and finally disappear altogether.

Where the horse is left in a state of nature, free to choose the ground over which he will run, the hoof grows just in proportion as it is worn away, and maintains itself without artificial means, in perfect condition. On the other hand, where the horse is turned out on low-lying and moist land, his feet grow to great length. This is the case, for example, in the Falkland Islands, where the whole surface is soft, mossy bog-land; and here the horses' feet grow to be twelve and fourteen inches in length and curl up in various ways, so that the animals can hardly walk upon them. The nails on the fingers and toes of man, if not shortened by abrasion from rough, manual labor, or cut and filed artificially, will grow to great length, and as they grow, curl inward and around the tips of the fingers and toes, attempting to form, what the toe-nail of the horse has formed, a hoof.

Man himself, who has recently taken to walking in a proud manner, only upon his hind legs, reserving his fore legs for painting, writing, gesticulating, and feeding himself, is also gradually losing the toes off his hind feet,—in many persons the little toe being already almost nothing more than a short and useless stump.

When you run your fingers down the fore legs of a horse you may feel distinctly two of his toes tucked away under the skin, and now known as the "splint bones." Where horses are used continuously to work on hard roads, this toe-nail or hoof wears itself away faster than it grows, hence the necessity for shoes.

It is this evolution from a five, and then a four toed animal, to an animal that walks on the nail of the middle toe, which makes the legs and the feet of the horse such a very delicate and difficult problem to the horse owner (Plate II.).

It cannot fail to be of value and interest to every one who deals with horses to trace their development as they increase in stature, and in brain, and with greater and greater complexity of teeth; at the same time that the number of toes decreases, according to the law which rules that the fewer the toes, the greater the speed; the swiftest bird being the ostrich and the fastest mammal the horse (Plate III.).

The teeth of the earliest prehistoric horses were short-crowned and covered with low, rounded knobs of enamel, like the teeth of monkeys, or pigs, or other omnivorous animals, and entirely different from the grinders of the horse of to-day. Along with the development of the legs and feet of the horse, from an animal destined to live in marshy and forest ground, to an animal obliged to take care of itself in open, grassy plains, came a corresponding change in the teeth, from short-crowned, to long-crowned (Plate IV.), enabling the animal to live on the hard, dry grasses which require thorough mastication, before they are of use as nutritious food.

The teeth of the modern horse are, perhaps, the most perfect grinding battery that could be devised. There is an external layer of enamel, and a second inner ring of enamel around the pit of the tooth, and these grinding one upon and across the other, as the horse chews, make a most effective crusher and masticator of his food.

The incisor teeth of the horse have all the great peculiarity, not found in the teeth of any other mammal, and only in the EquidÆ of comparatively recent geological periods, of an involution of the external surface of the tooth, by which what should properly be the apex, is carried deeply into the interior of the crown, forming a pit, the bottom of which becomes partially filled up with cement. As the tooth wears, the surface, besides the external enamel layer as in an ordinary, simple tooth, shows in addition a second inner ring of the same hard substance surrounding the pit, which, of course, adds greatly to the efficiency of the tooth as an organ for biting tough, fibrous substances. This pit, generally filled with particles of food, is conspicuous from its dark color, and constitutes the "mark" by which the age of the horse is judged, as, in consequence of its only extending to a certain depth in the crown, it becomes obliterated as the crown wears away, and then the tooth assumes the character of that of an ordinary incisor, consisting only of a core of dentine, surrounded by the external enamel layer. It is not quite so deep in the lower as in the upper teeth.

Between the canines and premolars is a space called the "bars" of a horse's mouth. It is here that the bit is placed, and not a few horsemen believe that this space in the horse's mouth has been gradually worn away by the use of bits until now it has become a regular bit-socket produced by the constant use of the horse by man. This is only one of the many absurd beliefs of the equinely wise in their generation. This space is no doubt the result of the lengthening of the jaw and head of the horse to reach his food. As his legs grew longer, placing him farther and farther above the ground, his neck grew longer and his jaw lengthened, and lengthened at a place where the grinding muscles would not interfere. The incisor teeth, three below and three above, developed more and more into effective nippers, and the premolars and molars into grinders of the most delicately complicated and complete kind.

It must not be supposed that this outline of the evolution of the horse is part patchwork and part surmise. On the contrary, the history of the evolution of the horse is the best-known illustration—and has been worked out with greater detail and success than any other example—of the doctrine of evolution by natural selection and adaptation to environment. "The skull of a man and the skull of a horse are composed of exactly the same number of bones, having the same general arrangement and relation to each other. Not only the individual bones, but every ridge and surface for the attachment of muscles and every hole for the passage of artery or nerve seen in one, can be traced in the other." The difference is mainly in this: in man the brain-case is very large and the face relatively of very small proportions; while in the horse the brain is very much reduced, and the face, especially the mouth, of great size. One can readily recall types of both animals where these differences sink to insignificance.

Even the man who is least interested in the ancestry of the horse cannot fail to see that the horse of to-day is the result of thousands of years of adaptation to his environment. His legs grew longer that he might go faster; his feet grew harder and encased themselves in a hoof; his head and neck grew longer that he might the more easily get his natural food; his teeth adapted themselves to the nipping, grinding, and mastication of that food; his bones, muscles, intestines, lungs, stomach, and general conformation inside and out, developed along the lines that have brought him to the point where he is far and away man's most useful sidepartner amongst all animals.

These matters are worth keeping in mind when you look over a horse with a view to his purchase. So far as your purse permits, you want the horse best adapted to your requirements. As you look him over, you have at least an intelligent notion of what you may expect from his past history and the points of the animal which indicate that he will bear out those expectations.

Let us suppose you want a harness horse for all-round work, one that will go single, double, or in a makeshift four. It is not required that he trot in 2.10, nor that he be able to be one of four to pull a loaded coach ten miles an hour.

First of all, he must see. Next he must have legs and feet to go on. Then he must have room for a furnace inside of him, to furnish the propelling force for those legs; and the more intelligence he has, and the more good-natured he appears, the better. Later, some of the more prominent good points and bad points of the horse will be noticed in detail, but it is as well to say at the start that the horse-dealer, or your most horsy friend, or the veterinary, avail little to find you the perfect horse.

All that reading, study, and experience can do is to avoid the worst faults, to keep in mind the salient good points, and then to make the very most of your purchase by care and training after he is your property. You may learn the good and bad points of a horse by heart and be as a babe in the hands of a clever horse-seller, whether he be professional or amateur. He knows the weaknesses, and also the good points, of what he has to sell, and you do not; and there are very few Launcelots in the horse business. We have all bought horses of a shrewd dealer and sold them again for five times what we paid; we have also bought horses and gladly disposed of them for one-fifth of the purchase price.

The main trouble in the whole matter is that buying and selling horses is looked upon by many people as either necromancy or thievery. It is neither. Study, intelligence, and experience are as necessary and as valuable in choosing a horse as in any other department of life, and in the end are just as valuable. Art critics have been fooled; book-worms have been deceived; lovers have been disappointed; financiers have gone into bankruptcy; educated men have been failures; but study, intelligence, and experience still rank high, none the less. It is possible that in this matter of choosing a horse the aleatory instinct in man comes to the fore and he is apt to think luck plays too great a part, but, aside from that, much the same qualities succeed here as elsewhere.