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.
[Illustration: PLATE III.--NEOHIPPARION
Intermediate stage in development of the horse, being about three
feet high, and having three complete toes]
[Illustration: PLATE IV.--SKULL OF HORSE EIGHT YEARS OLD
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.