Monkeys are usually divided into three kinds--apes, monkeys, and
baboons; but these do not include the American monkeys, which are really
more different from all those of the Old World than any of the
latter are from each other. Naturalists, therefore, divide the whole
monkey-tribe into two great families, inhabiting the Old and the New
World respectively; and, if we learn to remember the kind of differences
by which these several groups are distinguished, we shall be able
to understand something of the classification of animals, and the
difference between important and unimportant characters.
Taking first the Old World groups, they may be thus defined: apes have
no tails; monkeys have tails, which are usually long; while baboons have
short tails, and their faces, instead of being round and with a man-like
expression as in apes and monkeys, are long and more dog-like. These
differences are, however, by no means constant, and it is often
difficult to tell whether an animal should be classed as an ape, a
monkey, or a baboon. The Gibraltar ape, for example, though it has no
tail, is really a monkey, because it has callosities, or hard pads of
bare skin on which it sits, and cheek pouches in which it can stow away
food; the latter character being always absent in the true apes, while
both are present in most monkeys and baboons. All these animals,
however, from the largest ape to the smallest monkey, have the same
number of teeth as we have, and they are arranged in a similar manner,
although the tusks or canine teeth of the males are often large, like
those of a dog.
The American monkeys, on the other hand, with the exception of the
marmosets, have four additional grinding teeth (one in each jaw on
either side), and none of them have callosities, or cheek pouches. They
never have prominent snouts like the baboons; their nostrils are placed
wide apart and open sideways on the face; the tail, though sometimes
short, is never quite absent; and the thumb bends the same way as the
fingers, is generally very short and weak, and is often quite wanting.
We thus see that these American monkeys differ in a great number of
characters from those of the Eastern hemisphere; and they have this
further peculiarity, that many of them have prehensile or grasping
tails, which are never found in the monkeys of any other country.
This curious organ serves the purpose of a fifth hand. It has so much
muscular power that the animal can hang by it easily with the tip curled
round a branch, while it can also be used to pick up small objects with
almost as much ease and exactness as an elephant's trunk. In those
species which have it most perfectly formed it is very long and
powerful, and the end has the underside covered with bare skin, exactly
resembling that of the finger or palm of the hand and apparently equally
sensitive. One of the common kinds of monkeys that accompany street
organ-players has a prehensile tail, but not of the most perfect kind;
since in this species the tail is entirely clad with hair to the tip,
and seems to be used chiefly to steady the animal when sitting on a
branch by being twisted round another branch near it. The statement is
often erroneously made that all American monkeys have prehensile tails;
but the fact is that rather less than half the known kinds have them
so, the remainder having this organ either short and bushy, or long
and slender, but entirely without any power of grasping. All
prehensile-tailed monkeys are American, but all American monkeys are not
prehensile-tailed.
By remembering these characters it is easy, with a little observation,
to tell whether any strange monkey comes from America or from the Old
World. If it has bare seat-pads, or if when eating it fills its mouth
till its cheeks swell out like little bags, we may be sure it comes from
some part of Africa or Asia; while if it can curl up the end of its tail
so as to take hold of anything, it is certainly American. As all the
tailed monkeys of the Old World have seat-pads (or ischial callosities
as they are called in scientific language), and as all the American
monkeys have tails, but no seat-pads, this is the most constant external
character by which to distinguish them; and having done so we can look
for the other peculiarities of the American monkeys, especially the
distance apart of the nostrils and their lateral position.
The whole monkey-tribe is especially tropical, only a few kinds being
found in the warmer parts of the temperate zone. One inhabits the Rock
of Gibraltar, and there is one very like it in Japan, and these are the
two monkeys which live furthest from the equator. In the tropics they
become very abundant and increase in numbers and variety as we approach
the equator, where the climate is hot, moist, and equable, and where
flowers, fruits, and insects are to be found throughout the year. Africa
has about 55 different kinds, Asia and its islands about 60, while
America has 114, or almost exactly the same as Asia and Africa together.
Australia and its islands have no monkeys, nor has the great and
luxuriant island of New Guinea, whose magnificent forests seem so well
adapted for them. We will now give a short account of the different
kinds of monkeys inhabiting each of the tropical continents.
Africa possesses two of the great man-like apes--the gorilla and the
chimpanzee, the former being the largest ape known, and the one which,
on the whole, perhaps most resembles man, though its countenance is less
human than that of the chimpanzee. Both are found in West Africa, near
the equator, but they also inhabit the interior wherever there are great
forests; and Dr. Schweinfurth states that the chimpanzee inhabits the
country about the sources of the Shari River in 28° E. long. and 4° N.
lat.
The long-tailed monkeys of Africa are very numerous and varied. One
group has no cheek pouches and no thumb on the hand, and many of these
have long soft fur of varied colors. The most numerous group are the
Guenons, rather small long-tailed monkeys, very active and lively,
and often having their faces curiously marked with white or black, or
ornamented with whiskers or other tufts of hair; and they all have large
cheek pouches and good sized thumbs. Many of them are called green
monkeys, from the greenish yellow tint of their fur, and most of them
are well formed, pleasing animals. They are found only in tropical
Africa.
The baboons are larger but less numerous. They resemble dogs in the
general form and the length of the face or snout, but they have hands
with well-developed thumbs on both the fore and hind limbs; and this,
with something in the expression of the face and their habit of sitting
up and using their hands in a very human fashion, at once shows that
they belong to the monkey tribe. Many of them are very ugly, and in
their wild state they are the fiercest and most dangerous of monkeys.
Some have the tail very long, others of medium length, while it is
sometimes reduced to a mere stump, and all have large cheek pouches and
bare seat pads. They are found all over Africa, from Egypt to the Cape
of Good Hope; while one species, called the hamadryas, extends from
Abyssinia across the Red Sea into Arabia, and is the only baboon found
out of Africa. This species was known to the ancients, and it is often
represented in Egyptian sculptures, while mummies of it have been found
in the catacombs. The largest and most remarkable of all the baboons
is the mandrill of West Africa, whose swollen and hog-like face is
ornamented with stripes of vivid blue and scarlet. This animal has a
tail scarcely two inches long, while in size and strength it is not much
inferior to the gorilla. The large baboons go in bands, and are said to
be a match for any other animals in the African forests, and even to
attack and drive away the elephants from the districts they inhabit.
Turning now to Asia, we have first one of the best known of the large
man-like apes--the orang-outang, found only in the two large islands,
Borneo and Sumatra. The name is Malay, signifying "man of the woods,"
and it should be pronounced órang-óotan, the accent being on the first
syllable of both words. It is a very curious circumstance that, whereas
the gorilla and chimpanzee are both black, like the negroes of the same
country, the orang-outang is red or reddish brown, closely resembling
the color of the Malays and Dyaks who live in the Bornean forests.
Though very large and powerful, it is a harmless creature, feeding on
fruit, and never attacking any other animal except in self-defense. A
full-grown male orang-outang is rather more than four feet high, but
with a body as large as that of a stout man, and with enormously long
and powerful arms.
Another group of true apes inhabit Asia and the larger Asiatic islands,
and are in some respects the most remarkable of the whole family. These
are the Gibbons, or long-armed apes, which are generally of small size
and of a gentle disposition, but possessing the most wonderful agility.
In these creatures the arms are as long as the body and legs together,
and are so powerful that a gibbon will hang for hours suspended from
a branch, or swing to and fro and then throw itself a great distance
through the air. The arms, in fact, completely take the place of the
legs for traveling. Instead of jumping from bough to bough and running
on the branches, like other apes and monkeys, the gibbons move along
while hanging suspended in the air, stretching their arms from bough to
bough, and thus going hand over hand as a very active sailor will climb
along a rope. The strength of their arms is, however, so prodigious,
and their hold so sure, that they often loose one hand before they have
caught a bough with the other, thus seeming almost to fly through the
air by a series of swinging leaps; and they travel among the network of
interlacing boughs a hundred feet above the earth with as much ease and
certainty as we walk or run upon level ground, and with even greater
speed. These little animals scarcely ever come down to the ground of
their own accord; but when obliged to do so they run along almost erect,
with their long arms swinging round and round, as if trying to find some
tree or other object to climb upon. They are the only apes who naturally
walk without using their hands as well as their feet; but this does not
make them more like men, for it is evident that the attitude is not an
easy one, and is only adopted because the arms are habitually used to
swing by, and are therefore naturally held upward, instead of downward,
as they must be when walking on them.
The tailed monkeys of Asia consist of two groups, the first of which
have no cheek pouches, but always have very long tails, They are
true forest monkeys, very active and of a shy disposition. The most
remarkable of these is the long-nosed monkey of Borneo, which is very
large, of a pale brown color, and distinguished by possessing a long,
pointed, fleshy nose, totally unlike that of all other monkeys. Another
interesting species is the black and white entellus monkey of India,
called the "Hanuman," by the Hindoos, and considered sacred by them.
These animals are petted and fed, and at some of the temples numbers
of them come every day for the food which the priests, as well as the
people, provide for them.
The next group of Eastern monkeys are the Macaques, which are more like
baboons, and often run upon the ground. They are more bold and vicious
than the others. All have cheek pouches, and though some have long
tails, in others the tail is short, or reduced to a mere stump. In some
few this stump is so very short that there appears to be no tail, as in
the magot of North Africa and Gibraltar, and in an allied species that
inhabits Japan.