In Upper and Lower Guinea the Chimpanzee (_Troglodytes niger_) also establishes his dwelling on trees. He first makes choice of a large horizontal branch, which constitutes a sufficient floor for the agile animal. Above this branch he bends the neighbouring boughs, crosses them, and interlaces them so as to obtain a sort of framework. When this preliminary labour is accomplished, he collects dead wood or breaks up branches and adds them to the first. Before commencing he had taken care when choosing the site that the whole was so arranged that a fork was within reach to sustain the roof. He thus constructs a very sufficient shelter. These apes are sociable and prefer to live in each other's neighbourhood. They even go on excursions in rather large bands. Notwithstanding this, more than one or two cabins are never seen on the same tree; perhaps this is because the complicated conditions required for the construction are not likely to be realised several times on the same tree; perhaps also it is a desire for independence which impels the Chimpanzees not to live too near to each other.[92] [92] Savage, "Observations on the External Characters and Habits of the _Troglodytes niger_," _Boston Journal Nat. Hist._, 1843, pp. 362-376. The _Troglodytes calvus_, a relative of the preceding, inhabiting the same regions, as described by Du Chaillu, shows still more skill in raising his roof. A tree is always chosen for support. He breaks off boughs and fastens them by one end to the trunk, by the other to a large branch. To fix all these pieces he employs very strong creepers, which grow in abundance in his forests. Above this framework, which indicates remarkable ingenuity, the animal piles up large leaves, forming in layers well pressed down and quite impenetrable to the rain. The whole has the appearance of an open parasol. The ape sits on a branch beneath his handiwork, supporting himself against the trunk with one arm. He has thus an excellent shelter against the mid-day sun as well as against tropical showers. Male and female each possess a dwelling on two neighbouring trees, the principle of conjugal cohabitation not being admitted in this species. As to the child, it appears that it sleeps near its mother, until it is of age to lead an independent life.