Chimpanzees in the wild, Bossou, West Africa
Vertical space is essential for chimpanzees. Chimpanzees in the wild spend more than half of their days in trees, up as far as 30m high above the ground. We can observe a variety of natural behavioral patterns above the ground, such as climbing, eating leaves and fruits, making a bed and so on. It is highly recommended to construct some three-dimensional climbing structures in the captive chimpanzees' living environment in the aim to simulate the life style of wild chimpanzees.
In 1998, we have built a 15m high climbing structure, called "triple tower", made up of three towers and joined together in an equilateral triangle at the Primate Research Institute, Kyoto University (KUPRI) by adding each tower to the former structure. The former climbing structure of KUPRI, had built in 1995, was 8m high. Our chimpanzees at KUPRI spent 55.8% of the day in the upper part of the structure. Our observational data shows that our chimpanzees spend more than 80% of the day in the upper part of the triple tower.
The triple tower are supported by strong foundation and secured together with numerous cables. Additionally we use ropes, fire hoses and logs fastened at the triple tower to provide easy resting and climbing for the chimpanzees. These are like lianas in the wild that allow chimpanzees to move freely in every direction. Climbing and brachiating within these "artificial webs" they can easily avoid each other during squabbles and conflicts, escape injuries; even help them not to fall easily and directly to the ground.
Upon introducing the triple tower, we have noticed that a chance to observe a variety of natural behavior highly increased. For example, we can observe these behaviors below:
Crossing on the ropes.
We can observe our chimpanzees moving on the ropes in a variety of ways.
Looking at scenery. We can enjoy the beautiful scenery of Inuyama city from the top of the triple tower. Our chimpanzees seem to enjoy the landscape. Unlike to them, it is difficult for us, humans to climb up high as 15 m!
We can observe our chimpanzees as they bring up plants and objects onto the top of the triple tower and make their bed there.
The outdoor enclosure is kept lush and verdant, and since our chimpanzees love to use the triple tower, they spend a lot less time on the ground, thus the trees and bushes in the enclosure are “protected.”