The following is my translation of an article called: Affenwege von H.O.-Batavia. It appeared in a German popular science magazine, Kosmos Handweiser für Naturfreunde 1913, Heft 10, Seiten 382-383.
I'm not aware of any previous translation.
Trevor Dykes.

Ape routes by H.O.-Batavia
Kipling writes, in his enchanting Jungle Book, about permanent routes maintained by apes in the confusion of the trees in the jungle. For a long time I held this to be poetic exaggeration, until I was able to convince myself as to its truth.

At the beginning of 1911, for reasons of recuperation, I was inn Nongkodjadjar, a health resort at an elevation of 1400m found in the Tengger Mountains of East Java. The pavilion of the hotel in which I was residing lay on the edge of a rather deep gorge, and the necessity for rest, which was forced upon me by malaria, often drove me to observe the animal life through a pair of binoculars. My greatest interest fell upon the apes, which were drawn to the gorge day by day so as to harvest the fruits from the numerous ficus trees, or to pay a visit to the neighbouring maize fields. A troop of 20 to 25 animals passed almost regularly at 5 o'clock in the afternoons through the trees which mainly lay in my field of sight, and an impressive forest giant, whose fruits were apparently of little interest to the four-handed animals, regularly served as a bridge from one thicket to another despite, as I was able to convince myself, plenty of other trees being available which could have served the same purpose. Furthermore, only two strong branches were used, and these were at the same height on the trunk but spread in opposite directions. The apes came from a tree to the right, which was well covered, into a position in open view that could only be reached with an impressive leap to the thin, outermost twigs, from which they quickly worked their way to the strong branches. They followed each other at intervals of about a metre. Each ran along the ascending branch to the horizontal part, and each stopped for a moment in the middle of the branch in order, so it seemed, to relax and take a look around. Mothers with young at the breast took this opportunity to rearrange the position of their children in readiness for the next leaps. Then, they went slowly and carefully further along the trunk, along the horizontal part of the left branch and then, at a high gallop, aimed for a destination diagonally upwards, and this then allowed them, after a skilful bound of about 3m, to reach the branch of the next tree. -During the three months I spent at Nongkodjadjar, I observed this troop on many evenings and always saw them, as they took exactly the same route, and this also applied for apes travelling on their own. I observed the animals in all parts of the slope of the gorge and always, if they wanted to go from right to left, their route went via this tree. A different path was apparently available for the opposite direction.

A horde of apes provides a magnificent sight as they cross a chasm in full flight. The deep and steep gorges of the Tengger Mountains provided often enough with this view. One of my morning strolls was down an old post path that led along the edge of a deep chasm, the slopes of which were decked with isolated, massive jungle trees. To the side of the path stood a tall ficus tree, and from this I heard furious screams. A group of the black-grey Tengger apes with one or two red animals, as has regularly been reported by natural historians and, as I could hear, they were completely furious at having their breakfast disturbed, and very angry at this sudden appearance of a person in a white suit. The females, with arms slung around the young at the breast, slowly retreated to the other side of the tree; the juveniles climbed screeching into the higher branches, but the mature males came closer, sat themselves on the boughs above my head, and shook with vigour as they bared their teeth and threateningly shouted with a lively "igh-ogh-ugh" scream. It looked dangerous, but I did not allow myself to be put off, but rather I remained calm and tried to imitate the call. That was too much for the animals, so their leader gave the signal for flight, and the wild chase began. The females with young simply allowed themselves to drop to the lower lying branches of the tree, but the younger generation reacted with more energy. Upwards pointing branches served as spring boards and, with accomplished arcs, they flew through the air with flights of 3-4m across but 15 to 20m downwards. More watchfully, and now and then again willing to present a united front against the enemy, the mature males followed. Their deportment is the same for each. The body is bent, the head somewhat stretched forward, hands and feet are poised to grab. The branch of the lower part of the tree is gripped with the hands after a leap; it bends deeply with the burden, and then springs back upwards. This swing helps the ape bring its body up onto the branch, then run quickly along the branch, round the trunk and, with an accomplished bound, to reach the next lower lying tree. The image reminded me of a school of leaping dolphins in the moving sea. The massed foliage of the trees is in motion like powerful waves, and again and again the dark bodies of the apes break through the surface, and then fly through the air as if shot from a cannon. Finally, the ground of the gorge is reached, but the flight is not yet at an end. It carries on at another cliff of the chasm, but less energetically; this is because it involves climbing to the highest point of a tree and from there, in leaps, reaching the lower standing branches of the next high tree. When the danger is far enough away, then the urgency fades, and I can soon watch through binoculars as the society continues quietly with its breakfast on the other side of the gorge.

An index of more of my translations of old Kosmos articles can be found at:

Kosmos Translations Archive

A number of Mesozoic (and post-Mesozoic) location summaries can be found at Localities.