When travelling through some parts of the Amazonian forests, and looking up into an ancient tree, a number of little striped faces crowding a hole in the trunk may suddenly be seen gazing inquisitively down at the intruder who has disturbed their noonday sleep. These are Nyctipitheci, or night apes, which the Indians call ei-a, and are named also Douroucouli. Sleeping soundly during the day in some dark hollow, out of harm’s way, they come forth at night to prey on insects or small birds, which they hunt and capture,—as well as fruit. The body of the creature is about a foot long, and the tail fourteen inches, thickly covered with soft grey and brown fur. Its face is round, and encircled by a ruff of whitish fur. The forehead is of a light colour, and adorned with three black stripes,—which in one species meet at the top of it, and in another continue to the crown; the muzzle is somewhat flat, and the mouth and chin small. The ears are very short, scarcely appearing above the hair of the head; and the eyes are large and of a yellowish colour, imparting that staring expression observed in owls or night animals. From this they have obtained the name of owl-faced night apes. The creature has nails of the ordinary form to its fingers, and semi-opposable thumbs; but the molar teeth are studded with sharp points, showing that it lives chiefly on insects.
Though in the daytime it appears torpid and dull, yet at night, shaking off its drowsiness, its large dull eyes, which shrunk from the rays of the sun, are full of eager animation as it sets off in quest of its prey. So active and quicksighted is it, that it catches the rapidly-flying insects as they flit by, or chases the beetles as they run over the bark of the trees on which it lives.
Mr Bates describes a tame one he met with, which was excessively confiding in its disposition, very lively and nimble, and in no way mischievous. It delighted to be caressed by all persons who came into the house. It used to sleep in the hammock of its owner, or nestle in his bosom half the day as he lay reading. From the cleanliness of its habits, and the prettiness of its features and ways, it was a great favourite with every one. He himself had a similar pet, which was kept in a box, in which was placed a broad-mouthed glass jar. Into this it would dive when any one entered the room, and, turning round, thrust forth its inquisitive face to stare at the intruder. It was very active at night, giving vent at intervals to a hoarse cry, like the suppressed bark of a dog, and scampering about the room after cockroaches and spiders. Although it preferred insects, it ate all kinds of fruit, but would not touch either raw or cooked meat. Its brothers, when let loose about the house, are very useful in clearing the chambers of bats, as well as insects and vermin.
It is monogamous. The ei-a and its wife may often be discovered together tending their small family in some hollow trunk. Its cry is wonderfully loud, considering its small size; and curious as it may seem, is not unlike the roar of the jaguar. It can also hiss or spit in the fashion of an angry cat, while it utters a curious mew resembling the same creature. It sometimes gives a guttural, short, and rapidly-repeated bark.
There are several species of night monkeys with very similar habits.
It is difficult, except when they are in captivity, to obtain a correct idea of the habits of these interesting little, animals,—though, of course, when they are tamed, they must abandon some of those they possessed in a state of nature. Of their dispositions, however, a very fair notion may be formed from the way they behave when in captivity. The above descriptions refer only to a few of the numerous species of monkeys which exist in the South American forests, but as typical forms have been selected, a tolerable idea of the whole may be obtained.