# Handbook to the Primates/Indrisinae

THE ENDRINAS. SUB-FAMILY INDRISINÆ.
This, the last sub-family of the Lemuridæ, is considered to contain the highest members of the whole Sub-order. They are distinguished by having their fur abundant, longer and woolly above, shorter beneath, with the hands and feet haired to the tips of the digits. Their head, set at right angles to the spinal column, is rounded, the face elongated and naked, with a deep furrow separating the nostrils. The eyes are large, and have a third eyelid, or nictitating membrane, to draw across the pupil during the day. The ears, which are naked inside and fringed ​on the outside, are moderately long and buried in the fur, but are less movable at will than is the case with the Galagos. Their fore-limbs are much shorter than the hind ones. The arms, which are united to the body by a parachute-like fold of integument, have long, narrow, and strong hands, of which the thumb is short, set far back, and but little opposable. The rest of the fingers, except the index, which is short, are long and slender, and terminate in a round disc. The feet are elongate, and the great toe, which is freely opposable to the other toes, is very large and broad, being, indeed, nearly as wide as the rest of the digits together; the remaining toes are united by a membrane as far as the second segment. The females have the mammæ situated on the breast.
In the skull the facial region is relatively small, and the cranial region relatively large. The external nostrils communicate with a cavity on the underlying bone; the pre-maxillary bones are deeply excavated in front, and the anterior perforations in the bony palate, behind the incisor teeth, are large. The lower jaw has its angle large, produced backwards, the line of union of its two halves being long, and its lateral movements very limited. In regard to their dentition, the number of the milk-teeth in the young individual is greater than that of the permanent set in the adult, the formula of the former being I 2/2, C 1/1, P 2/3 [M 3/3], while that of the latter is I 2/2, C 1/0, P 2/2, M 3/3, the lower canine and one lower pre-molar having disappeared. In the upper jaw the incisors are very small, the outer one standing behind the inner one, with a space between the former and the canine; the canines are long, curved behind, and set close up to the anterior pre-molar. The pre-molars are longer than they are broad, laterally compressed, and present to the outside one main triangular cusp with a small accessory cusp on each ​side, the posterior tooth of the series having a hind inner cusp. The anterior and median molars are four-cusped, of which the outer and inner pairs are separated by a longitudinal groove; to the outside they have one supernumerary cusp on each main cusp, and one between them. The median molar is the largest tooth of the jaw, and the posterior is small, triangular and three-cusped. Of the lower jaw, the outer pair of the long, and almost horizontally protruding incisors, is larger than the inner pair, and is separated by a space from the anterior pre-molar. Of the elongate laterally compressed pre-molars, the anterior is the larger, and is vertically taller than its fellows, being slightly depressed forward and curved behind; the posterior pre-molar has one cusp. The molars have four cusps, of which the inner ones alternate with the outer cusps.
The intestinal canal in the Indrisinæ is very long, the cæcum, or blind diverticulum at the junction of its two portions, being extremely long and large, occupying, indeed, a great part of the abdominal cavity. The main arteries of the fore- and hind-limbs do not break up into a rete mirabile, or series of small parallel vessels, as in many other Lemuroids.
In this group, while the sense of smell is very perfect, that of hearing is less acute than in the other Sub-families; and that of touch conspicuously blunt, both in the fingers and toes, which are chiefly climbing and not tactile and prehensile organs, as they are in the corresponding limbs of the Anthropoids. The female never produces more than one young at a birth.
The convolutions of the brain are few, but they are more complicated than in many of the South American Monkeys. In very young individuals the cerebellum is more covered by the cerebrum than it is in the adult.
​The species of this Sub-family are confined to the island of Madagascar. Our knowledge of their general characters, anatomical structure and habits, is very complete, through the researches, both in the field, of M. Grandidier, and in the study, of Prof. Alphonse Milne-Edwards. These results are published in their magnificent "Histoire de Madagascar," to which the reader is referred for fuller information.
The Indrisinæ, on account of their superior organisation, and especially their relatively large brain, are considered to be the highest of all the Lemuroids. They are essentially arboreal. If they come to the ground they sit upright on their hind-legs, and progress by jumps, holding their arms above their heads. They are easily tamed, and become gentle in confinement; but they are not very intelligent. The Endrinas "never manifest in any very marked manner," so MM. Milne-Edwards and Grandidier tell us, "the passions that affect the Apes so vividly; their countenance, almost as immobile as that of an herbivorous or carnivorous animal, exhibits neither anger nor pleasure. In captivity they do not seek to be caressed; they appear neither to become attached to their master, nor to take interest in anything about them." Many of their actions, however, and the peculiar sounds they often utter, recall those of Monkeys.
Some of the species are diurnal and others nocturnal.
The Sub-family has been divided into three genera, Avahis with one species; Propithecus, with three species, and Indris with a single species. All its members are remarkable for the extraordinary amount of variation in the coloration of their fur.
THE AVAHI LEMURS. GENUS AVAHIS.
Avahi, Jourdan, C. R., Journal l'Inst., ii., no. 62, p. 231 (1834).
Avahis, Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 320 (with full synonymy).
This genus is monotypic, containing but a single species, whose characters include necessarily those of the genus.
I. THE WOOLLY AVAHI. AVAHIS LANIGER.
Lemur laniger, Gm., Syst. Nat., i., p. 44, no. 10 (1788).
Microrhynchus laniger, Jourdan, Thèse inaug. Soc. Phys., Grenoble, 1834; Mivart, P. Z. S., 1866, p. 151, pi. xv.
Avahis laniger, Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., p. 325 (with full synonymy), Atlas, pls. 9, 10.
(Plate X.)
Characters.—Fur woolly; the head nearly round; the face short in proportion to the head; muzzle short, covered with hair; the nose and region of the chin hairy; nose-pad on lip large; nostrils opening into a cavity on the upper lip below the skin. Eyes large, the pupil vertical; ears small, concealed in fur. Tail a little longer than the body; body short, stumpy. Third, fourth and fifth fingers flattened; third and fourth toes united by a membrane as far as the first joint.
PLATE X.
THE WOOLLY AVAHI.
​Cranium more vaulted and the muzzle remarkably shorter than in the genera Indris and Propithecus; eye-sockets very large; the space between the eyes hollow. Temporal ridges not uniting into a single median ridge. Nasal bones projecting as far as the front end of the very small pre-maxillary bone. Lower jaw remarkably deep and broad behind; line of union of its two halves nearly half the length of the jaw, and in a straight line with the incisor teeth. Toothless space in front of upper jaw greater than in the other two genera. Dentition of the upper jaw: incisors small, the outer larger than the inner, set close to the canines and not at the inner edge of the toothless space; canines vertically short; pre-molars, with no inner cusp, but having a prominent outer cingulum (a character seen in no other species of Lemur); molars, four-cusped. Lower jaw: incisors larger than in the two other genera, and less horizontal, the inner ones more slender than the outer. Anterior and posterior molars, five-cusped. Hind margin of palate reaching to the middle of the median molar. Central bone of wrist wanting (of all Primates agreeing in this character only with Man, the Chimpanzees, the Gentle- and Sportive-Lemurs and the Endrina); fourth digit of the hands and feet longest. Tail long. The small intestine not spirally coiled upon itself, but folded many times transversely.
Hair long, woolly, dark Mouse-grey at base, reddish-brown in the middle, black at the tips. Face broad, entirely covered with short greyish-brown hairs; nose-pad alone nude. Ears concealed and covered by rufous hair; pupil of eye very contractile, very narrow and linear during the day; across the forehead and over the eyes a transverse lunulate whitish band, margined anteriorly by a black band. Back greyish-brown, the nape darker; a patch over the rump, and the base of the tail and buttocks white, washed with rufous; back and inner side of thighs and round the arms whitish; a narrow fringe on the lower margin of arms and legs ashy-grey, washed with rufous; fore-arm, hands and feet rusty-brown; tail bright dark red, deepest at its extremity. Under side and inner surface of limbs grey, washed with rufous. Length of body, 12½ inches; tail, 15¾ inches.
​Of this species there are two forms, an eastern and a northern, the latter being always smaller in size, with the fur lighter and less rusty. In some varieties the upper surface is dark rusty-red all over, and the inner sides of the limbs pure white. Examples from the north-west coast are constantly smaller; the head rounder, and the facial hairs grey; no white band on the forehead; upper surface bright yellowish-brown; tail rusty-grey; under side of hind-limbs pure white, the under surface and inner side of the arms whitish. The variation in coloration is due to the middle part of the hairs, which in typical specimens is rusty-red, but is yellow in the above-mentioned form. Hands and feet grey.
Young.—Ashy-grey, slightly washed with red.
Distribution.—The Woolly Avahi seems to inhabit only the forests of the parallel ranges of the mountains which face the whole eastern coast of Madagascar; it extends round the bay of Passandava on the west coast, opposite to the northern termination of this eastern range of mountains.
Habits.—This species—the smallest of the Indrisinæ—being essentially nocturnal, is torpid during the day, and is the wildest and least docile of the family. The first specimen of the "Avahi," the name by which this animal is known among the Anatala tribe, was brought to Europe by Sonnerat, the French traveller, in 1781, and nearly half a century elapsed before a second one was obtained. Since then several specimens have been kept in captivity in the different zoological gardens of Europe.
THE SIFAKAS. GENUS PROPITHECUS.
Propithecus, Bennett, P. Z. S., 1832, p. 20; Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 288 (with full synonymy).
​The characters which distinguish this genus from Avahis and Indris are the following: The fur with which they are covered is more silky than woolly, and in general appearance is white, more or less washed with yellow, varying to red or black. The head is very slightly longer than it is broad, with a black and almost naked muzzle; the ears, half buried in the fur, are flatter and wider than in Indris, the inner surface being naked and black, and the outer haired. The nostrils are large and semilunar in shape. The tail is long. The index-finger is not united by a membrane to the others; their hands and feet are in a much less degree organs of prehension than in most of the other Lemurs.
The skull in proportionate length is intermediate between that of Avahis and Indris. Compared with Avahis it is less vaulted, its muzzle is longer, and the orbits are smaller. The space between the eyes is high, and not depressed, on account of the presence of a large air-cavity in the underlying bone. Their nasal bones do not reach as far forward in front as the level of the incisor teeth. In the dentition of the upper jaw, the incisors protrude somewhat in front, and are dilated laterally in a regular series—thus distinguishing the genus Propithecus from Lemur,—the inner incisors being larger than the outer ones, with their tips approximating. Between the canine and the anterior pre-molar there is a short gap. The anterior and median molars have the cusps of the crown alternate; the posterior has them opposite. In the lower jaw the incisors are shorter and stronger than in Avahis, and the molars are four-cusped.
The genus Propithecus contains three species; (1) The Diademed Sifaka (P. diadema), (2) Verreaux's Sifaka (P. ​verreauxi), both having numerous very marked varieties; and (3) the Crowned Sifaka (P. coronatus).
These species are found all round the coasts of Madagascar; as well in the luxuriant forests on the east side as in the arid deserts and the sparsely-wooded plains of the south-western and western coasts. Of the three species of the genus, one (P. diadema) is confined to the eastern and southern coasts, the other two (P. verreauxi and P. coronatus) are found only on the west coast. More or less distinctly coloured varieties or races of these three species occur, and it is very remarkable that each of them is rigorously restricted to localities distinct from that of the typical species.
I. THE DIADEMED SIFAKA. PROPITHECUS DIADEMA.
Propithecus diadema, Bennett, P. Z. S., 1832, p. 20; Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., p. 296 (with full synonymy), Atlas, pl. 1-3.
Characters.—Fur long, silky, the muzzle naked. Head shorter and rounder than in the other species of the genus; thumb slender, like the toes, set far back, free; great toe very strong, and in the same plane with the other digits; a marked depression exists in the skull behind the orbits. Body, 21 inches; tail, 19 inches in length.
Forehead crossed by a broad white bar; cheeks in front of the ears, and the under side of the chin, white or fulvous white; face black, with a few short black hairs. Back of head, neck, shoulders, sides of body, outer sides of arms, sometimes grey, but generally very dark brown, merging into dark grey on the lower back. Tail at its root washed with orange-yellow, paler in the middle, greyish-white at its extremity. Fore-arm, lower part of arm, sacral region, and external face of hind-limbs, bright ​orange-yellow. Hands black-haired to the ends of the fingers, but with long and yellow tufts of hair at the tips. Feet pale orange and haired to the nails. Chest dark brown. Under surface white, or white tinged with yellow, or dark brownish-grey. Internal face of the fore-limbs grey, from the intermixture of black hairs; that of the hind-limbs pale yellow.
Young.—Similar in colour to the adults, but lighter; the frontal band yellow, not white; limbs light yellow.
Varieties.—Several varieties of this species—the "Simpona" of the natives—have been described, of which the following deserve special notice:—
THE SILKY SIFAKA. PROPITHECUS SERICEUS.
Face black, with flesh-coloured spots; the body entirely white, faintly washed with yellow; the base of the tail washed with rust-red. It is of the same size as the type-form, and appears to be only an albino variety. Specimens showing every gradation in coloration between that of the type and the absolute albino are now well known. This form, however, is more or less restricted to the narrow belts of forest on the eastern side of the mountains in the north-east of Madagascar, between the rivers Lokoi and Bemarivo, a region conterminous with that inhabited by the typical species.
MILNE-EDWARDS' SIFAKA. PROPITHECUS EDWARDSI.
Differs from the true P. diadema in having the face slightly haired between the eyes and on the chin; a patch on each flank rufous-white or orange-yellow, separated by a reddish-black band; a spot at the root of the tail bright rusty-red, and all the rest of body black, washed slightly with rufous. The young are like the parents. This form is also of the ​same size as the type, but is a melanistic variety, for a series of specimens show every intermediate shade between that here described and the Black Sifaka (P. holomelas), which is of an entirely black colour, and inhabits, as has been shown by MM. Milne-Edwards and Grandidier, the same region as P. edwardsi.
Distribution.—The typical form of the species is confined to the extended region on the east coast of Madagascar lying between the Bay of Antongil on the north, and the River Masora in the south, in the forest-belts on the eastern aspect of the mountains, where rain falls abundantly and the whole region is covered with luxuriant vegetation. Its melanistic variety (P. edwardsi) extends south from the Masora as far as the Faraouny river, but it ranges to higher and colder altitudes on the mountains; while its albinistic variety (P. sericeus) lives in the somewhat warmer region to the north of Antongil Bay, each being, to south and north respectively, conterminous with the central habitat of the typical form.
II. VERREAUX'S SIFAKA. PROPITHECUS VERREAUXI.
Propithecus verreauxi, Grandid., Album de l'île de la Réunion, iv., pp. 153-162, pls. 1, 2 (1867); Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 305 (with full synonymy), Atlas, pls. 4, 6, 8.
Characters.—Fur short and woolly; face entirely naked; head longer than broad; a well-marked swelling of the skull between the eyes; the upper incisors sub-equal. Smaller and more robust than P. diadema, the head longer, the hair on the limbs shorter, the tail longer.
​Body yellowish-white; a spot on the top of the head dark brown, sometimes washed with rufous, separated from the face by a white frontal bar. Face black; eyes brownish-yellow; interior of ears black, and naked; a grey patch on the middle of the back; outer aspect of the fore-arms, and hind-legs, ashy-grey; rest of the body white. Hands and feet white. Tail yellowish-white. Length of body, 18 inches; of tail, 22 inches.
Young.—Entirely white, with a dark brown spot on the head; the under surface of the body washed with rufous.
Varieties.—Two well-marked varieties of this species are known, both of which were for many years considered to be distinct species. Continued exploration has, however, now resulted in the accumulation in various museums of a large amount of material from many localities, and this proves that the two forms really belong to but one species.
VON DER DECKEN'S SIFAKA. PROPITHECUS DECKENI.
Differs from the true P. verreauxi in having the face and ears black, and the body otherwise entirely grey, or white, washed more or less with yellow (sometimes rufous on the limbs); or of an ashy-grey colour on the loins, neck, and outer aspect of the limbs; the under side bright rufous; chest and inner sides of the limbs rusty-white, with a fulvous spot at the base of the tail. Specimens from the forests of the interior have a grey spot on the back of the neck expanding into a collar, which is absent in those from the coast. An albino variety comes, so far as is at present known, only from the wooded belts on the extensive plains between the rivers Manambolo and Manjaray, on the west coast.
COQUEREL'S SIFAKA. PROPITHECUS COQUERELI.
(Plate XI.)
Has the face naked and black, but the centre of the nose white; the ears showing as black points amid the white hair; head and back of neck white, slightly washed with yellow; outer side of arm and fore-arm dark maroon-red, the lower border fringed with long white hair; a maroon patch on the upper and outer surface of the thighs, lighter on the chest and central part of the belly. Loins dark rusty-grey; hands white; tail rusty-grey.
Distribution.—Verreaux's Sifaka, with its two varieties, is confined to the small thin woods on the sandy and almost rain-less plains along the western and southern coasts of Madagascar. The type-form is found, alone, and unassociated, in the extensive plains of Mesozoic geological formation—between the southern base of the eastern range of mountains and the River Tsidsubon, which flows into the sea on the west coast. Von der Decken's Sifaka inhabits the middle of the west coast, while Coquerel's Sifaka has its home further to the north. It occupies the area between the south side of Narendry Bay and the north side of Bembatoka Bay, the Betsiboka River being its extreme southern limit.
Though first observed by Flacourt, and described by him in 1661, Verreaux's Sifaka remained practically unknown from that time till re-discovered by M. Grandidier in 1867.
III. THE CROWNED SIFAKA. PROPITHECUS CORONATUS.
Propithecus coronatus, Milne-Edwards, Rev. Scient., 1871, p. 224; id. et Grandid., Hist. Nat. Madag., Mamm., i., p. 316 (with full synonymy), Atlas, pl. 7.
PLATE XI.
COQUEREL'S SIFAKA.
​Characters.—Muzzle very broad and naked; nose-pad wide; inside of ears naked. Face, top of head, sides of neck, and throat, deep brownish-black; muzzle black; a band across the temples, and a streak down the nose, white. Ears black inside, fringed externally with white; neck and upper surface white, washed with rust-colour on the limbs and root of the tail. Tail, hands, and feet, pure white. Under side rich orange-red, darker across the chest; inside of limbs white, washed with rufous. Of the same size as P. verreauxi.
Cranium larger in all its parts than in other species. Nasal bones elongated beyond the incisor teeth; nose very flat, this being due to the large air-cavity (called false nose) in the jaw-bone below, connected with the nose. The length and breadth of the muzzle gives a peculiar expression to the face of P. coronatus.
This species, like the preceding, is subject to considerable variation.
The whole head is sometimes grey, washed with rufous; the upper surface and root of the tail white, flushed with rust-colour.
In examples living further in the interior than the habitat of the type (Bay of Bembatoka), the back is more rufous, the neck has a large grey or brown patch, and the chest is very dark brownish rust-colour. The abdomen and the inner sides of the limbs are bright red.
Distribution.—This species occurs on the north-west coast of Madagascar, between the Bay of Mozamba to the north and the River Manjaray on the south, ranging over the country to a considerable distance into the interior. The lighter-coloured specimens come from the more northern range of the species, while the more brightly-marked varieties have been obtained ​in the interior more to the south. It is curious, remarks M. Grandidier, to find races and species of the same genus so exactly restricted, that one has only to cross a river, not necessarily large, in order to obtain on one bank certain species of Propithecus, whereas those occurring on the opposite bank may be of a very distinct species or race. To what influence in their surroundings can all these variations be ascribed? One can understand that species inhabiting a wooded and humid country, or living among granitic mountains (as P. diadema does), would differ in size and fur from other members of the same genus which live in dry and arid plains (as in the case of P. verreauxi); but how can the great variations that occur in members of the same species living a few miles, and perhaps only a few metres, apart, be explained, when the external conditions are almost the same?
Habits.—The habits of the different species of Sifaka are very similar. They live in companies of six or eight, and are very gentle and inoffensive animals, wearing always a most melancholy expression, and, as a rule, being morose, inactive, and more silent than other Lemurs. They rarely live long in captivity. In their native state they are most alert in the morning and evening, as during the heat of the day they conceal themselves amid the foliage of the trees. When asleep or in repose, the head is dropped on the chest and buried between the arms, the tail rolled up on itself and disposed between the hind-legs. The Sifakas live exclusively on vegetable substances—leaves, fruits and flowers—their diet not being varied, as in the other groups, by small birds, eggs, or insects. Their life is almost entirely arboreal, for which the muscles of their hands and feet, as well as the parachute-like fold of skin between their arms and body, and their peculiarly hook-like fingers, are most fitted. The young one is carried about by its mother on her back, its hands grasping her arm-pits tightly. The Sifakas are held in great veneration or fear by the natives of Madagascar, and are never intentionally killed by them.
PLATE XII.
THE ENDRINA.
THE ENDRINAS. GENUS INDRIS.
Indris, Cuv. et Geoffr., Mag. Encycl., 2 ed. Ann. i., p. 46 (1796); Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 330 (with full synonymy).
This genus is, like the first of the sub-family, monotypic, no second species having rewarded the many explorers of Madagascar in the long period that has elapsed since its solitary species was discovered. This species is known as
I. THE ENDRINA. INDRIS BREVICAUDATUS.
Indris brevicaudatus, Geoffr., Mag. Encycl., 2 ed. Ann., p. 46 (1796).
Indris variegatus, Gray, Ann. and Mag. N. H. (4), x., p., 474 (1872).
Indris brevicaudatus, Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 336 (with full synonymy), Atlas, pls. xi.-xii.
(Plate XII.)
Characters.—The peculiar features of the species, as given below, are necessarily those of the genus also.
Fur long and woolly, extremely variable in its coloration. Head rounded, longer than it is broad; muzzle moderately long, covered with very short hairs; fingers and toes haired to the finger-tips; external ears rounded, exserted, and more developed than in Avahis or Propithecus, with long and tufted ​hair forming a fringe all round. Median nose-pad high and narrow; pupil of eye circular; body elongated; arms about one quarter of the length of the legs; hands very long, the four outer fingers united by a membrane as far as the first joint, and the toes to the centre of their middle segments; hands and feet haired to the tips. Tail rudimentary.
Skull longer and less vaulted; brain-case proportionately more compressed from side to side; the muzzle longer, and the orbit smaller, than in Avahis; floor of orbit higher than the bony margin of the jaw; inter-orbital space flat; nasal bones, though long, not extending in front as far as the end of the pre-maxillary bone; mandible elongated, narrower, and less deep than in Avahis. Bony palate short, posterior margin thickened, and with a foramen behind the posterior molar; line of union of the two halves of the lower jaw shorter than in Avahis; its angle very large. No central bone in the wrist (or carpus); hind-limb (with or without the foot), compared with the fore-limb (with or without the hand), longer than in any other of the Primates, except Galago. Upper teeth: Incisors, sub-equal, set close together and subject to variation in size; canine, vertically taller than, and not separated by a gap from, the pre-molar; pre-molars compressed, and having an inner cusp; anterior molars, four-cusped, with the supplementary cusps weak, and with no oblique ridge; anterior and median, with their outer and inner cusps opposite; posterior molar, which is the smallest grinder of the jaw—four-cusped, with transverse, but no oblique ridges. Lower teeth: Incisors, with marked longitudinal ridges to the outside (peculiar to this genus); pre-molars sub-equal; molars all four-cusped, and the posterior ones expanded behind.
Brain highly organised. A large laryngeal pouch (present ​also in the fœtus), but differing from that of the Apes, is placed between the gullet and windpipe, communicating with the latter by an orifice: main arteries of the fore- and hind-limbs not broken up into a rete mirabile of small parallel vessels, as in many species of Lemurs.
Face naked, sometimes blackish, generally dark grey; lips downy; head, neck, back, shoulders, arms, and hands, deep black; fore-arms faintly washed with rufous; a large patch, widening from the middle of the back downwards to the lower back, rump, and root of the tail pure white, washed with orange or red; a patch on each flank, pale, becoming rufous or greyish-white, separated from the rump-spot by black bands continuing down the outer side of the inner face of the thighs, and the front and inner sides of the legs; thighs ashy-grey, their upper two-thirds greyish, becoming black on the front, and ashy-grey on the hinder surface, of the leg. Feet black; tail stumpy, fawn-colour, brownish-grey at the tip; under side rusty brown; abdomen grey; heel rufous.
Many varieties of this species have been met with. Of these, some have the top of the head and between the eyes greyish-white, mixed here and there with black; jaws and throat, grey; ears, neck, back and upper part of arms, black; the fore-arms grey; the hands black; a patch on the lower back ashy-grey; flanks bright rufous; legs grey; band on front of the thighs black; heel bright rufous.
Other examples have a mark over each eyebrow, the fore-limbs nearly to the hands, the hinder part of the thighs, the legs from the knee to the ankle, and the whole under side iron-grey; the ankles and hind part of the heels white, yellow below. (Indris variegatus, Gray.)
All stages between the forms here described and complete ​albinos are known; so that the various differences observed prove them to be only individual variations of the same species.
Distribution.—The Endrina is confined to the woods looking eastward, on the two high ranges along the eastern coast, between the Bay of Antongil on the north and the River Masora on the south.
Habits.—The "Endrina," "Bàbakòto," or "Amboanala" (Dog of the Forest), as the natives variously name this species, has the same habits as the Sifakas. It is the largest of the Lemurs, and is diurnal. It derives its appellation of "Dog of the Forest" from the doleful, dog-like howls which it utters. In this habit it differs, therefore, from most of the other groups (except the True Lemurs), which are, as a rule, rather silent. Its powerful voice is due to the distensible resonator which it possesses in its laryngeal pouch, described above. Essentially diurnal, the Endrinas live in small companies, and feed only on vegetable diet. The hook-like fingers of their hands are better adapted for climbing than for prehension, and much of their food is, indeed, seized by the mouth. They are entirely arboreal, and move about the trees in an erect position, rarely coming to the ground. The "Bàbakòto" is held in great veneration by most of the native tribes.
M. Pollen gives several other particulars of these Lemurs, and of the curious notions of the Malagasy respecting them. Their native name is "Bàbakòto," literally "Father-child" (or "boy"), not "Indri," as stated by Sonnerat, who discovered the species. Indri, or Indry, is a Malagasy word meaning "lo!" or "behold!" and was probably mistaken by him and other Europeans for the vernacular name of the animal when the ​natives exclaimed, "Indry izy!" ("There he is!"). Dr. A. Vinson says that, in passing through the great Eastern forest, he was assailed for two days by the incessant clamour of these Lemurs, which seem to keep together in large companies, but are invisible in the dense foliage. The natives have a superstitious veneration for these animals, and consider them as sacred. They believe that their ancestors change after death into Bàbakòto, and that the trees where these animals live supply infallible remedies against otherwise incurable diseases. The people say that it is very dangerous to kill these Lemurs with spears, because if a spear is hurled against one of them it seizes the spear in its flight without being itself hurt, and in its turn stabs with certain aim those attacking it. They also relate that when the female has borne a young one, she takes the little creature in her arms and tosses it to her mate, who is seated on a neighbouring tree, and that he throws it back to the female. If the little one does not fall to the ground after being subjected to this exercise for a dozen times, the parents bring it up with the greatest care; but, if the contrary event happens, they abandon it, not even troubling to pick it up. In certain parts of Madagascar, says M. Pollen, the people employ the Bàbakòto in chasing birds, and they say that it renders as good service as a Dog. These animals, although principally fruit-eaters, do not disdain small birds, which they catch with much skill, in order to eat their brains.
This Lemuroid is probably the best known to travellers in Madagascar, at least by ear, as no one can travel along the most frequented route in the island, that from Tamatave to Antananarivo, without often hearing the cries of these animals as he passes through the great forest. They are not often seen, but their long drawn-out melancholy cries are frequently heard, a ​strange wailing sound, as if of people in distress, or children crying. Dr. Vinson says that the Bètànimèna tribe let these animals at liberty if they find them in captivity, and give them burial should they find them dead. They relate that a certain tribe, at war with its neighbours, took refuge in the forests; their enemies, in pursuing them, led by the sound of human voices, as they supposed, found before them a troop of Bàbakòto, at whose appearance they were struck with terror. They fled, persuaded that the fugitives had been changed into beasts. These, on the other hand, vowed eternal gratitude to the Lemurs who had saved them, and have ever since religiously refrained from injuring them in any way.