[Illustration: THE RED FOOTED NIGHT-MONKEY.]
{171}DISTRIBUTION.--This species is rather rare, but it has been obtained
at Ega and at Tabatinga on the Upper Amazons; on the Ucayali, and near
Yurimaguas on the Huallaga River--in the warm and humid virgin forests--in
fact, generally along the Peruvian Amazons.
In speaking of his collections made at Ega on the Upper Amazons, which he
describes as a fine field for a Natural History collector, Mr. Bates gives
an interesting account of the Night-Apes, called "Ei-á" by the Indians,
observed by him during his various journeys. "Of these I found two species
(_Nyctipithecus trivirgatus_ and _N. felinus_) closely related to each
other, but nevertheless quite distinct, as both inhabit the same forests,
namely, those of the higher and drier lands, without mingling with each
other or inter-crossing. They sleep all day long in hollow trees, and come
forth to prey on insects and eat fruits only in the night. One cannot help
being struck by this curious modification of the American type of Monkeys,
for the Owl-faced Night-Apes have evidently sprung from the same stock as
the rest of the _Cebidæ_, as they do not differ much in all essential
points from the Whaiapu-Sais (_Callithrix_) and the Sai-miris
(_Chrysothrix_). They have nails of the ordinary form on all their fingers,
and semi-opposable thumbs; but the molar teeth (contrary to what is usual
in the _Cebidæ_) are studded with sharp points, showing that their
nocturnal food is principally insects.
"I kept a pet animal of _N. trivirgatus_ for many months, a young one
having been given to me by an Indian compadre as a present from my
newly-baptized godson. These Monkeys, although sleeping by day, are aroused
by the least noise, so that, when a person passes by a tree in which a
number of them are concealed, he is startled by the sudden apparition of
{172}a group of little striped faces crowding a hole in a trunk. It was in
this way that my compadre discovered the colony from which the one given to
me was taken. I was obliged to keep my pet chained up; it, therefore, never
became thoroughly familiar. I once saw, however, an individual of the other
species (_N. felinus_) which was most amusingly tame. It was as lively and
nimble as the _Cebi_, but not so mischievous, and far more confiding in its
disposition, delighting to be caressed by all persons who came into the
house. But its owner, the Municipal Judge of Ega, Dr. Carlos Mariana, had
treated it for many weeks with the greatest kindness, allowing it to keep
with him at night in his hammock, and to nestle in his bosom half the day
as he lay reading. It was a great favourite with everyone, from the
cleanliness of its habits and the prettiness of its features and ways. My
own pet was kept in a box in which was placed a broad-mouthed glass jar;
into this it would dive, head foremost, when anyone entered the room,
turning round inside, and thrusting forth its inquisitive face an instant
afterwards to stare at the intruder. It was very active at night, venting
at frequent intervals a hoarse cry like the suppressed barking of a dog,
and scampering about the room, to the length of its tether, after
cockroaches and spiders. In climbing between the box and the wall it
straddled the space, resting its hands on the palms and tips of the
outstretched fingers with the knuckles bent at an acute angle, and thus
mounted to the top with the greatest facility. Although seeming to prefer
insects, it ate all kinds of fruit, but would not touch raw or cooked meat,
and was very seldom thirsty. I was told by persons who had kept these
Monkeys loose about the house, that they cleared the chambers of bats as
well as insect vermin. When approached gently, my Ei-á allowed {173}itself
to be caressed; but when handled roughly it always took alarm, biting
severely, striking with its little hands, and making a hissing noise like a
Cat.
"I have mentioned the near relationship of the Night-Apes to the Sai-miris
(_Chrysothrix_), which are among the commonest of the ordinary Monkeys of
the American forests. This near relationship is the more necessary to be
borne in mind, as some Zoologists have drawn a comparison between them and
the nocturnal Apes of the Lemur family, inhabiting Ceylon and Java, and it
might be inferred that our American Ei-ás were related more closely to
these Old World forms than they are to the rest of the New World Monkeys.
The large nocturnal eyes and short ears of the Eastern Lemurs are simply
resemblances of analogy, and merely show that a few species, belonging to
utterly dissimilar families, have been made similar by being adapted to
similar modes of life...."