THE ABYSSINIAN GREEN MONKEY
(Cercopithecus æthiops)
AS a familiar example of a very large assemblage of exclusively African long-tailed monkeys collectively known as guenons (from a French word signifying to make grimaces), no better species could have been selected for illustration than the Abyssinian green monkey. This monkey, which like its cousin the common green monkey (Cercopithecus callitrichus, orsabæus) may be seen in almost all menageries and on many street-organs, is an East African species; whereas the true green monkey is West African, ranging from Senegambia through Sierra Leone to northern Liberia, but has been introduced into some of the Cape Verd and West Indian Islands, where it still occurs plentifully, at least in Barbados.
From the guereza monkeys (Colobus) of Africa, a guenon may be distinguished at a glance by its well-developed thumbs; while these monkeys also differ from guerezas, as well as from their Asiatic relatives the langurs, by having well-developed pouches in their cheeks for storing food. There is, however, another African group of monkeys, the mangabeys (Cercocebus), some of which are more difficult to distinguish from guenons, although the majority are recognisable at a glance by their flesh-coloured eyelids, whence the name of white eyelid monkeys. When this character fails, resource must be had to the cheek-teeth, of which the last pair in the lower jaw is less complex in a guenon than in a mangabey; but to examine the back-teeth of a live monkey is not an experiment every one would desire to try!
To any one but a specialist, the very large number of representatives of the guenons are exceedingly difficult to class and identify. The matter has, however, been somewhat simplified by arranging the species in thirteen groups, each characterised by the possession of some particular distinctive feature or features. The well-known diana monkey (C. diana) represents, for instance, a group in which there are long, upwardly directed, snow-white whiskers associated with blackish or dark red under-parts, a white brow-band, distinctly white areas on the chest and the inside of the arms, a chin-tuft, and a white stripe on the outer side of the thigh. The members of the spot-nosed group, again, as typified byC. petaurista, are recognisable at a glance by having a large, heart-shaped white spot on the tip of the nose. The green monkeys, on the other hand, belong to a group (typified by the Abyssinian species) somewhat less easy to recognise, but characterised by the absence of black on the outer surface of the arms, which may be coloured like the body, but are usually, as in the plate, somewhat paler and grey. The face is nearly always black, but may be mottled or freckled with pigment; and, except in one species, thewhiskers grow upwards and backwards over the ears. The western species, the aforesaidC. callitrichus, lacks the white brow-band present in the Abyssinian species and nearly all the other members of the group; the species forming the subject of the plate being further distinguished by the black-speckled yellowish olive colour of the fur of the back, the long, white whiskers, sharply defined from the hair of the rest of the head, and the presence of a tuft of hair at the root of the tail.
monkey
Guenons may be regarded as some of the most typical of all monkeys, and those in which monkey-tricks attain their fullest development. They live more on fruits and seeds than either the guerezas or the langurs, which feed largely on leaves and the young shoots of trees. Guenons are indeed probably to some extent omnivorous, whereas the members of the other two groups are wholly herbivorous. This difference in the matter of diet is correlated with the presence of cheek-pouches and the simple character of the stomach in the guenons, whereas the other two groups lack pouches in the cheek, but, in compensation, have the stomach folded and divided in a complex manner.
In their native forests green monkeys and their relatives associate in large troops, which keep up a constant chattering, and each of which is under the leadership and control of an old male. Each troop appears to have its own particular territory in the forest; and if one party intrude on the domain of its neighbour, a fierce contest takes place, which does not end until the invaders have been driven out or have proved themselves the stronger. A survival of this custom may be noticed even among monkeys in a menagerie, where each species or individual will take up one portion of the cage for its own particular use, and resolutely defend it against the other occupants of the enclosure.
From the other members of the genus the patas monkey (C. patas) and its relatives are specially distinguished by their red colouring and large size, and they should perhaps form a genus by themselves.