The members of this genus may easily be recognised by their very Dog-like face, their muzzle being greatly elongated and truncated at the end, with the nostrils set in the truncated termination. Their eyes are directed downwards along the visage. In form and massiveness of body and in length of tail they vary very much. Their fore- and hind-limbs are nearly equal in length, and consequently they progress on all fours, with the palms of the hands and the soles of the feet flat to the ground. Their "fore-paws" are, however, very efficient hands, which some species use very dexterously in turning over stones in their search for food. Their feet are long. Their hair is grizzled or ringed with various colours.
The facial region of the skull is more developed in this genus relatively to the flattened brain-case, than in other Monkeys. In several of the species longitudinal osseous ridges are developed on the bones of the upper jaws, especially in the adult males, adding to the hideousness of the countenance of these animals. The neck is elongated. The radius is longer than the humerus (or arm-bone), and the elbow projection of the ulna (of the fore-arm), named the olecranon process, is prolonged upwards beyond what occurs in Man. The thumb, though relatively shorter than in Man, is much longer proportionately than in other Monkeys, reaching to the middle of the first joint of the forefinger.
Both halves of the liver are much sub-divided.
Gestation lasts seven months, and the young are suckled for six months.
The Baboons are the lowest of the Catarrhine or Old World Monkeys. Most of them are large, ferocious, dangerous, and gregarious animals, and when disturbed or alarmed they give utterance to screams, barks, and guttural murmurs.
Both Dr. Emil Holub and Sir Richard Burton have spoken of the ferocity of the Baboons. "The South African farmers," says the first-named naturalist, "complain of these animals as a great and perpetual nuisance." They were always on the look-out, and no sooner was a field or a garden left unguarded than they would be down at once, breaking through the hedges and devouring the crops. They were likewise very destructive amongst the Sheep. If a shepherd happened to leave his post for ever so short a time, or even to fall asleep, the Baboons, who had been watching their chance from the heights, would be down upon the flock in the valley, and, seizing the Lambs and ripping up their stomachs with their teeth, would feast upon the milk they contained, then leaving the poor mangled victim writhing on the ground. Then they would lose no time in repeating the terrible operation upon another. "About the middle of the morning," says Dr. Holub, "we started eastwards in the hope of catching the herd at their drinking-place.... When we had advanced some distance along the hill we found ourselves approaching the pool ... and could distinctly hear the hoarse barking of the Baboons. Looking across to the opposite side, about 300 yards away, we caught sight of a herd of seven, only four of them full-grown; they seemed to pause and scan us carefully before they decamped to a glen on the right. With all speed we followed them.... As one of our party had only small shot, and the other nothing but a stick, I insisted upon their remaining close at my side, knowing that a full-grown Baboon, when infuriated, is as dangerous a foe as a Leopard.... Behind one of the embankments we took our position. Only a few minutes had elapsed when we could distinctly recognise them as a herd of Baboons. The boy said he was quite sure that they were on their way to the water; but to our surprise they did not make any further advance. A quarter of an hour passed—half an hour—still no symptom of their approach. All at once, as if they had started from the earth by magic, at the open end of the pond, not sixty yards from our place of ambush, stood two huge males.... Being anxious to watch the movements of the animals I refrained from firing, and determined to see what would follow next. Both Baboons sprang towards the water, and leaning down, drank till they were satisfied; then, having gravely stretched themselves, they stalked away solemnly on all fours in the direction of the herd. There was little doubt, therefore, that they had been sent forward to reconnoitre; for as soon as they got back, the entire herd put itself in motion, and made its way towards the pond. There were mothers taking care of their little ones; there were the half-grown animals, the boys and girls of the company; but there did not seem to be more than three or four full-grown males. At first only one Baboon at a time came to the water's edge, and having taken its draught retired to the rest; but when about ten of them had thus ventured separately, they began to come in small groups, leaving the others rolling and jumping on the sand.... It was not long before two males—the same, I had no doubt, which we had noticed before—came and squatted themselves one on each side of the little creek.... Crack went my rifle. But instead of either of them dropping, the two Baboons started up; by a mutual instinct they both clutched their noses, gave a ringing bark and scampered off. The whole herd took the alarm, and joining in the shrieking clamour were soon lost to sight."
On another occasion Dr. Holub and his servant had a rencontre with a herd of Baboons. He writes:—"We caught sight of them in one of the glens. They were on the further side, and being anxious to obtain a specimen of their skulls, I fired and killed one Baboon; but unfortunately for me, the creature fell into the river. At my second shot I wounded two more. This induced the right wing of the herd to retreat; but the main body kept their ground, and the left flank, moreover, assumed the aggressive, and commenced pelting us so vigorously with stones, that, remembering that I had only one cartridge, I considered it far more prudent to withdraw than to run the risk of a hand-to-hand encounter." On a still further occasion the same well-known traveller says: "I was turning to leave the ravine when some stones came pattering down the rocks in my direction. I soon became aware that the stones were being designedly aimed at me; and, looking up, I saw a herd of Baboons."
"The Nyanyi or Cynocephalus," writes Sir Richard Burton in his "Lake Regions of Central Africa," "in the jungles of Usukuma attains the size of a Greyhound, and, according to the natives, there are three varieties of colour—red, black and yellow. They are the terror of the neighbouring districts; women never dare to approach their haunts; they set the Leopard at defiance, and when in a large body, they do not, it is said, fear the Lion."
"Baboons often show their passion," as Mr. Darwin has related, "and threaten their enemies in a very odd manner, namely, by opening their mouths widely, as in the act of yawning. Mr. Bartlett has often seen two Baboons, when first placed in the same compartment, sitting opposite to each other, and then alternately opening their mouths; and this action seems frequently to end in a real yawn. Mr. Bartlett believes that both animals wish to show to each other that they are provided with a formidable set of teeth, as is undoubtedly the case. As I could hardly credit the reality of this yawning gesture, Mr. Bartlett insulted an old Baboon and put him into a violent passion; and he almost immediately thus acted.... Baboons likewise show their anger, as was observed by Brehm with those which he kept alive in Abyssinia, in another manner, namely, by striking the ground with one hand, 'like an angry man striking the table with his fist.' I have seen this movement with the Baboons in the Zoological Gardens; but sometimes the action seems rather to represent the searching for a stone or other object in their beds of straw.... With several species of Baboons, the ridge of the forehead projects much over the eyes, and is studded with a few long hairs, representing our eyebrows. These animals are always looking about them, and in order to look upwards they raise their eyebrows. They have thus, as it would appear, acquired the habit of frequently moving the latter. However this may be, many kinds of Monkeys, especially the Baboons, when angered, or in any way excited, rapidly and incessantly move their eyebrows up and down, as well as the hairy skin of their foreheads."
Baboons are confined to the African continent and to Arabia, to the region, indeed, termed Ethiopian, as defined by Sclater and Wallace. They live chiefly on the ground, especially in rocky and barren hills, and less frequently among trees, for which their equally long front and hind limbs are not so well adapted. Mr. H. H. Johnson, C.B., now H.M. Commissioner in Nyasa-land, found, however, on his Kilimanjaro Expedition, that Baboons were singularly abundant in the big trees at Taveita, on the rise to that mountain. Their food consists of fruits and Lizards, but principally of insects, which they search for under stones, turning these over with their hands. They are, indeed, nearly omnivorous, as the reader will have gathered from Dr. Holub's observations.