Gorillas & Chimpanzees

by R. L. Garner

The skull of the young gorilla is much like that of the chimpanzee, and remains so until he approaches the adult state; but as he approaches this period, the ridge above the eyes becomes more prominent, and at the same time a sharp, bony ridge begins to develop along the temples, and continues around the back of the head on that part of the skull called the occiput. At this point it is intersected by another ridge at right angles to it. This is called the sagittal ridge, and runs along the top of the head towards the face; but on the forehead it flattens nearly to the level of the skull, and divides into two very low ridges, which turn off to a point above the eyes and merges into that ridge. These appear to be a continuous part of the skull, and are not joined to it by sutures. The mesial crest in very old specimens rises to the height of nearly two inches above the surface of the skull, and imparts to it a fierce and savage aspect; but in the living animal the crests are not seen, as the depressions between them are filled with large muscles, which make the head look very much larger than it would otherwise. These crests affect only the exterior of the skull, and do not appear to alter the form or size of the brain cavity, which is larger in proportion than that of the chimpanzee. These crests are peculiar to the male gorilla, and the female skull shows no trace of them.

PLATE I

PLATE II

There is at least one case in which this crest has failed to develop in the male. By reference to the series of skulls found in the cuts given herewith, No. 6 is that of an adult male, which I know to be such, as I dissected him and prepared the skeleton myself. He was killed in the basin of Lake Fernan Vaz, not more than two or three hours from my cage, and his body was brought to me at once. A good idea of his size can be obtained by reference to another cut given herewith, where I have some natives skinning him. In this picture he is sitting flat on the sand; his body is limp, and is somewhat shorter than it was in life, and yet it can be seen that the top of his head is higher than the hip of the man who is holding him. On the left of the gorilla, in the foreground, sits the man who killed him. He is sitting on a log, and it did not occur to me until too late to place them side by side in order to make a comparison. The body and head of this gorilla as he sits measured nearly four feet from the base of the spinal column to the top of the head. I did not weigh him, but made an estimate by lifting him in my hand, and believed he weighed at least 240 lbs. Yet he was not an old specimen, but if compared to No. 7, in which the crests are well developed, it is found to be larger, and other things point to the fact that he was older.

I am aware that one specimen of itself does not prove anything, but it shows in this case that this ape does not always develop that crest. His head was surmounted by the red crown which we have described, and No. 1, which is the skull of Othello, had the same mark. He was captured near the place where No. 6 was killed. No. 2, which is the skull of a young female nearly four years old, had the same, and she was also captured in the same basin, but on the opposite side of the lake.

The facial bones of No. 6 showed that the animal had received a severe blow in early life, but the fragments had knitted together, and the effect could not be seen in the face of the ape while alive. In this same picture it will be noticed that the lower lip hangs down so low that the mouth is opened. The lip is very massive and mobile, and in this character he resembles the negro. The lower lip is much thicker and more flexible than the upper.

No. 8 is the skull of a large male from Lake Izanga, which is on the south side of the Ogowe River, more than a hundred miles from the coast, and is one of the three centres of population mentioned. I do not know its history. It was presented to me by Mr. James Deemin, an English trader with whom I travelled many days in the Ogowe River; and I wish here to take occasion to express my sincere thanks to him for the many kindnesses extended to me.

No. 5 is the skull of an adult female. By comparing it in profile to No. 6 it will be seen that they resemble, but the muzzle of the latter projects a little more, and the curvature of the skull across the top is less: the distance a little greater.