Chapter V: The White-Nosed Saki. Pithecia Albinasa

_Pithecia albinasa_, Is. Geoffr. et Dev., C. R., xxvii., p. 498 (1848);
id., Arch. Mus., v., p. 559 (1845); Gervais in Castelnau, Expéd. Am. Sud,
ii., p. 16, fig. 2 (1855); Scl., P. Z. S., 1881, p. 258, pl. xxix.

_Chiropotes albinasa_, Gray, Cat. Monkeys Brit. Mus., p. 61 (1870).

(_Plate XVII._)

PLATE XVII.

{189}CHARACTERS.--Uniformly, but rather sparingly, covered with black hairs. Face black, naked; nose broad and naked, and with a bright scarlet line down its bridge, broadening out on the latter and on the upper lip; tip of nose white, from the presence of a few white hairs.

Long hairs on the head falling to all sides; tail long and clothed to the tip with long hairs hanging down from its under side, slightly prehensile. Length of the body, 15 inches; of the tail, 18 inches.

DISTRIBUTION.--Amazonia.

HABITS.--The White-Nosed Saki, which might much more appropriately have been called the "Red-Nosed Saki," is very rare; its habits are quite unknown. The type specimen in the Paris Museum remained unique in Europe from 1848 till 1881, when a living specimen was brought to the Zoological Gardens in London.

THE HOWLERS. SUB-FAMILY MYCETINÆ.

This sub-family embraces only one genus, which is very distinct from all the others. The Howlers are the largest of the South American Apes, and are characterised by their thick unwieldy body, their pyramidal head, and small facial angle, owing to their long, somewhat Dog-faced muzzle. The angle of the lower jaw is very large and massive, and their chief characteristic is the conspicuous thickening of the throat, owing to the great enlargement of the hyoid bones--which are widely inflated and cavernous--to form the curious vocal organ which the males of these animals possess, and by which their voice can be so augmented as to be heard at a distance of several miles.[11] The skull is truncated behind {190}in the male (less so in the female) for the reception of the vocal apparatus. Their incisor teeth are small and equal, the canines are prominent and have an oblique ridge across the crown from the outer front, to the inner hind, cusp, and the upper molars are large. The tail is powerful and prehensile, naked towards the tip, where it is tactile and very sensitive. The thumb is movable, the face is naked, and the chin bearded. Some have short, and some have long, fur over their bodies, but it is generally more plentiful about the head. In appearance they are the most unattractive and repulsive of the American Monkeys. Their intelligence is also of a very low order.

The roof of the brain-case is depressed; the plane of the opening for the passage of the spinal-cord from the brain is almost perpendicular to that of the base of the skull; the condyles for the articulation of the neck are situated as far back as possible. Sir William Flower, in his valuable monograph on the brain of _Mycetes_, has shown that the frontal lobes are small and the cerebral hemispheres only just cover the cerebellum. In regard to its grooves and convolutions, the main brain (_cerebrum_) of _Mycetes_ can be distinguished from that of all other Monkeys. The whole organ is small as compared with the size of the animal; it wants the roundness and fulness of that of the Spider-Monkeys (_Ateles_) and of the Capuchins (_Cebus_). Its surface markings are comparatively few and simple, and depart remarkably from the ordinary type seen in the order. In the Old World Apes there is a striking similarity in the character of the surface markings of their cerebral hemispheres. There is a slight ascensive development from _Cercopithecus_ towards _Hylobates_; and further complications overlying the same primitive type--such as large proportionate {191}size, and complexity of convolutions--are observed in the Chimpanzee and Gorilla, leading up to the brain of Man. Among the New World genera there is a much greater divergence. Among the Capuchins (_Cebus_), and among them only, there is a precise repetition of the Old World type; but in the genus _Mycetes_ we have modifications in which there is no parallel among the Catarrhine (or Old World) series. There is an absence in its brain of signs of serial elevation; and it exhibits a great dissimilarity to all, even the lowest of the Old World forms, and to those American Monkeys, which in brain-character closely resemble Old World Apes. It shows an affinity in some of its more striking characters to such low forms of New World Apes as _Nyctipithecus_. The low type of brain is in keeping, as Sir William Flower further observes, with their surly and untameable disposition, and with the observation that their intelligence is of a very different order from that of their neighbours, the Spider-Monkeys and Capuchins of higher cerebral organisation.

"When Howlers are seen in the forest," remarks Mr. Bates, "there are generally three or four of them mounted on the topmost branches of a tree. It does not appear that their harrowing roar is emitted from sudden alarm; at least, it was not so in captive individuals. It is probable, however, that the noise serves to intimidate their enemies." The muscular power employed in giving vent to their cavernous roar appears to be small. Their food consists chiefly of fruits and leaves.

In colour the Howlers vary very much. The young of both sexes often differ from their parents, and the females from the males, and there is also great individual variation.

The geographical distribution of some of the species is very restricted, several of them being confined to a special district {192}of the Amazon, into which no other species intrudes. They are found, however, from Eastern Guatemala to Paraguay.

THE HOWLERS. GENUS ALOUATTA.

_Alouatta_, Lacép., Mém. Inst., iii., p. 490 (1801).

_Mycetes_, Illig., Prodr. Syst. Mamm., p. 70 (1811).

_Stentor_, Geoffr., Ann. Mus., xix., p. 107 (1812).

The characters of the genus _Mycetes_, which is the only one of the sub-family, are the same as those given above under the sub-family heading.

The genus contains six well-recognised species. According to Mr. Wallace the red and black species of the Amazon have females of the same colour as the males. Humboldt also remarks, speaking of the thousands of Arguatoes (_M. seniculus_) which he observed in the provinces of Cumana, Caracas, and in Guiana, that he never saw any change in the reddish-brown fur of the back and shoulders, either in isolated individuals or whole troops. Many of the species, however, do have the sexes of quite different colours.

The Howlers are semi-nocturnal in their habits, uttering their cries late in the evening and before sunrise, and also on the approach of rain. (_Wallace._)

When a _Mycetes_ is shot it always hangs to the tree, even if quite dead, and does not fall till the muscles of the feet and tail relax.

The species of this genus range through Central America, Colombia, and the Amazonian region, to Southern Brazil, Bolivia, and Paraguay.

PLATE XVIII.

{193}I. THE RED HOWLER. ALOUATTA SENICULUS.

_Simia seniculus_, Linn., Syst. Nat., i., p. 37 (1766).

_Alouatta seniculus_, Lacép., Mém. de l'Inst., iii., p. 489 (1800).

_Stentor ursina_ (nec fig.), Humb. and Bonpl., Obs. Zool., v., p. 354
(1811).

_Mycetes seniculus_, Illig., Prod. Syst. Mamm., p. 70 (1811); Geoffr.,
Cat. Méth. Primates, p. 52 (1851); Schl., Mus. Pays Bas, vii., p. 156
(1876); Gray, Cat. Monkeys Brit. Mus., p. 39 (1870, part.).

_Stentor seniculus_, Geoffr., Ann. Mus., xix., p. 108 (1812).

_Mycetes stramineus_, Spix, Sim. et Vespert., Bras., p. 45, pl. 31 (1823;
nec Geoffr.).

_Mycetes chrysurus_, Geoffr., Mém. Mus., xvii., p. 66 (1829).

_Mycetes auratus_, Gray, Ann. N. H., xvi., p. 220 (1845); id. Cat.
Monkeys Brit. Mus., p. 40 (1870).

_Mycetes laniger_, Gray, Ann. N. H., xvi, p. 219 (1845); id. Cat. Monkeys
Brit. Mus., p. 40.

_Aluatta senicula_, Slack, Proc. Acad. Nat. Sci. Philad., 1862, p. 517.

(_Plate XVIII._)

CHARACTERS.--Head, neck, limbs and tail, dark chestnut-brown; back and sides golden-yellow; beard in the full-grown male long, the hair golden-yellow at the root, otherwise chestnut-brown; face naked, black; chest naked, the abdomen sparsely covered with long brown hairs.

The hair of the body is soft. The tail varies in colour in individual specimens, being sometimes, at its termination, of the same colour as the back, and sometimes bright golden-yellow. The _mammæ_ are occasionally situated in the _axillæ_ (or arm-pits). Length of body, 19½ inches; tail, 20 inches.

YOUNG.--Of the same colour as the parents, only a little darker, the hair hard and rigid.

{194}DISTRIBUTION.--Brazil; New Granada; Venezuela; Copataza river, Ecuador; Eastern Peru, along the Ucayali and Huallaga rivers.

HABITS.--The Red Howlers always travel in large companies, keeping to the forests of the low lands and shores of the rivers. "We stopped," writes Humboldt, "to observe the Howling Monkeys, which, to the number of thirty or forty, crossed the road by passing in a long file from one tree to another upon the horizontal and intersecting branches." On another occasion the same celebrated naturalist records that "on approaching a group of trees, we perceived numerous bands of Arguatoes going as in a procession from one tree to another with extreme slowness. A male was followed by a great number of females, several of which carried their young on their shoulders. The uniformity with which the Arguatoes execute their movements is extremely striking. Whenever the branches of neighbouring trees do not touch, the male that leads the band suspends himself by the callous and prehensile part of his tail; and letting fall the rest of his body, swings himself till in one of his oscillations he reaches the neighbouring branch. The whole file performs the same action on the same spot. It is almost superfluous to add how dubious is the assertion that the Arguatoes and other Monkeys with prehensile tails form a sort of chain, in order to reach the opposite side of a river. We had opportunities, during five years, of observing thousands of these animals, and for this very reason we place no confidence in these stories."

"The Arguatoes are sometimes accused of abandoning their young, that they may be more free for flight when pursued by Indian hunters. It is said that mothers have been {195}seen taking off their young from their shoulders and throwing them down to the foot of the tree. I am inclined to believe that a movement merely accidental has been mistaken for one that was premeditated. The Arguatoes, on account of their mournful aspect and their uniform howlings, are at once detested and calumniated by the Indians."

Mr. Wallace, in a paper "On the Monkeys of the Amazon," in the "Proceedings of the Zoological Society," says: "Humboldt observes that the tremendous noise which these Howlers make can only be accounted for by the great number of individuals that unite in its production. My own observations, and the unanimous testimony of the Indians, prove this not to be the case, one individual alone making the howling, which is certainly of a remarkable depth and volume and curiously modulated; but on closely remarking the suddenness with which it ceases and again commences, it is evident that it is produced by one animal, which is generally a full-grown male."

The flesh of this species is very good to eat, and furnishes the principal food of the inhabitants of the regions in which it abounds.