Tokiwa Zoo
Asian Forest: Gibbons

Kenji Wako (Professor at Osaka University of Arts and Zoo Designer, Author for Tokiwa Zoo)
Jonas Homburg, Monika Fiby (Editors for ZooLex)

Published 21 Dec 2017



3-Chome 4-1, Norisada, Ube, Yamaguchi Japan
Phone: +81 836 213541
URL: http://www.tokiwapark.jp/zoo


Habitat environment exhibition


Family:Species:Common Name:Capacity:
Hylobatidae Hylobates lar White-handed gibbon 8


  • 2015 Urban Park Competition Director-General Award of the Ministry of Land, Infrastructure and Transport (Parks and Open Space Association of Japan)


Asian Forest zone at Tokiwa Zoo displays several Asian primate species together in typical naturalistic environments. The aim is to closely replicate the animals’ natural forest habitats encouraging natural behaviors and enhancing visitor experience.

The exhibit for the white-handed gibbons consists of two islands and adjacent indoor facilities. Each island houses a gibbon family group composed of a breeding pair with offspring. A 4m wide water moat separates the animals from the visitors. Fallen trees of 5m connect the indoor huts to the islands across the water moat. The side of the building facing these bridges is additionally secured by overhanging electric wires, so the gibbons cannot climb the walls and escape. The two sleeping huts are modeled after typical Sumatran farm houses and thus represent the characteristic local architecture.

The enclosure reproduces the structure of the Sumatran island forest which allows the gibbons three-dimensional movement, and their habitat, based on a habitat survey of the island, elicits active brachiation jumping among branches.



The entire Asian Forest Zone comprises 6000m² of which the gibbon area is about 1800m². Island 1 measures 165m² with an indoor room for the animals of 6m². Island 2 has 182m² outdoors and two indoor rooms of 6.2m² each. The outdoor visitor path covers 380m², the indoor viewing 11m².

Space allocation in square meters:

Use:Indoors:Outdoors:Total Exhibit:



These are the costs for the whole Asian Forest Zone.

Yen 688,000,000 including 5% for design.



21 March 2015


Beginning: 2011

  • Total design: Kenji Wako, Osaka, Japan
  • Basic plan, basic design, implemented desig: Kukan-Soken. Co.,Ltd., Osaka, Japan


Beginning: 2012


walter.gif This is a climatic diagram for the closest weather station.



A habitat survey was conducted on Sumatra in order to reproduce an environment which would encourage the gibbons’ characteristic behavior, brachiation. A result was that their brachiation is not a movement parallel to the ground but a three-dimensional movement behavior up, down, left, and right in the forest. To provide a satisfying exhibit for this behavior, various tall trees such as Celtis sinensis, Quercus serrata, Ilex rotunda, Apjananthe aspera and Quercus glauca from around the park where the zoo is located were selected and transplanted to the site. Under these trees, particularly medium and low trees with horizontally extended branches were chosen, such as quercus and ubame oak (Quercus phillyraeoides) with a height of about 3-5 m, making it easy to brachiate up and down among the planted trees. Trees with a particular tree shape have been arranged above and below, because bending of branches is also important for the brachiation. For landscaping, hedge bamboo, Alocasia odora and Ostrich ferns, etc. were planted as accents. Also, in planting, the focus was laid on providing leafy shade from trees with a crown to protect animals from summer heat.

During the design of the facility, a 1/50 clay model was used to confirm the location of the trees and to understand the relationship of heights, shapes, etc. by re-arranging tree models with typical tree shapes.

Maintaining the planting in the enclosure is especially important because many plants may wither due to animals' feeding and branch folding. Periodic sowing and replanting are necessary, and trees (eg. Fatsia japonica, Evergreen lindera, etc.) that animals are not fond of are also introduced. In addition, regular pruning is necessary along the water moat to maintain a certain distance between the animal area and the observation aisle so that the primates do not escape using the branches of tall trees inside and outside the enclosure.

The plant list specifies the Latin names of the plants used for this exhibit.


Shade from tall trees softens summer heat to the animals. In addition to the living trees, the enclosure area is also equipped and structured with fallen trees, tree stems, branches, ropes and rocks creating a three-dimensional environment for the primates. The specific choice and arrangement of the trees in their exhibit allows the gibbons to follow their natural movement patterns. As a result, the gibbons swiftly branchiate up, down, left and right.

Several feeders and feeding boxes are devised and placed throughout the enclosures that blend in with the landscape by using natural objects such as trees or artificial fruits.
The primates are also fed leaves of the trees called ‘green food’ to encourage this feeding behavior over time. Giving the leaves of selected trees for food and a smaller amount of conventional fruits reduces sugar intake.

As the two islands are physically separated and have their own indoor rooms, they can be used housing two groups of gibbons in separate enclosures. The larger island has two sleeping rooms for housing individuals separated, when necessary, while the smaller island has only one sleeping room. All indoor rooms have wooden boards and large branches for the gibbons to sit on. Windows let in natural light and additional lamps are mounted to light up the room.



The keepers reach the islands via stones placed in the shallow water. If necessary, they can also use a boat. Since the ground of the islands is mainly soil and ground covering plants, cleaning is basically only to remove feces. It takes less time and labor compared to cleaning with high pressure water. It is also safe from the sanitation aspect and there is less smell. Water pipes were installed for cleaning.

The sleeping rooms can be reached from a keeper room through metal bar doors that can be securely locked by two bolts. All shifting gates from the indoor to the outdoor exhibits are operated manually, at island no. one it is horizontal, and at island no. two they are vertical with counter weights.



The Asian Forest zone is the first themed area on the visitors’ way throughout the zoo. The path leads around the islands and provides different viewpoints.

The gibbons can be observed without any visual barrier across the water moat. The gibbons’ resting area is designed in the style of regional villages to make it easier to grasp the regional environment. One of the two larger sleeping rooms (for island 2) can be viewed by the visitors through a glass window while standing under a canopy which also offers an additional view on the island.

A wooden swaying bridge leads to a Sumatra island rural-style house located on the edge of the gibbon islet so visitors can observe the gibbons while crossing the water. On the visitors’ side, a fallen tree is used as a bench. In addition, sculptures of animals created by local chainsaw artists are placed in the area and e.g. arranged as benches.



Because the thematic zone is centered on primates living in Asian forests, the theme of interpretive signs conveys the structure of their troop in an easy-to-understand manner. The signage not only shows the gibbons’ way of life in a small pair-type group but also a schematic diagram of brachiation.

In the last interpretive sign of the complex, the theme compares human society with the life of animals. At first sight, a troop of primates looks like a human family with parents, children and grandchildren, but the questions is whether their troop makes up a unit that can be called a family. For this reason, an important question for humans is asked in this zone with the title “What is a family”.

A voice guide explanation about the animals is also available for smartphones.



The two enclosures allow to house family groups separately. The second indoor room connected to island 2 offers additional space for separating individuals if necessary. The gibbons can be securely shifted from indoors to outdoors and are locked out during the day.



The behavior of the white-handed gibbons is investigated.



The zoo takes part in a Japanese conservation breeding project.
The habitats in the park are investigated, including insects, aquatic organisms and wild birds.



Publicity activities were conducted with citizens, for example holding a workshop to make the plans public to citizens, incorporating their opinions and holding a backyard tour during the construction period. Furthermore, the zoo is attracting tourists from all over the country by organizing planned tours with local accommodation companies.



© Kenji Wako, 2017


Site Plan

Site Plan

© Kenji Wako, edited by Jonas Homburg, 2017


Picture Views

Picture Views

© Kenji Wako, 2017


White-hande gibbon

White-hande gibbon

© Tokiwa Zoo, 2017


View from the entrance

1. View from the entrance

© Tokiwa Zoo, 2015


Gibbon island

2. Gibbon island

© Tokiwa Zoo, 2015


Water moat

3. Water moat

© Tokiwa Zoo, 2017


Trees for brachiating

4. Trees for brachiating

© Tokiwa Zoo, 2015



5. Brachiation

© Tokiwa Zoo, 2015


Gibbons in the trees

6. Gibbons in the trees

© Tokiwa Zoo, 2015


Feeding box in the trees

7. Feeding box in the trees

© Tokiwa Zoo, 2017


Bridge to sleeping hut

8. Bridge to sleeping hut

© Tokiwa Zoo, 2017


Sleeping hut 2

9. Sleeping hut 2

© Tokiwa Zoo, 2015


Swinging bridge

10. Swinging bridge

© Tokiwa Zoo, 2015


Wooden bench

11. Wooden bench

© Tokiwa Zoo, 2015



12. Signage

© Tokiwa Zoo, 2017


Information panel

13. Information panel

© Tokiwa Zoo, 2017


Pattern of brachiation

14. Pattern of brachiation

© Tokiwa Zoo, 2015


Keeper access to sleeping hut 1

15. Keeper access to sleeping hut 1

© Tokiwa Zoo, 2017


Sleeping room in hut 1

16. Sleeping room in hut 1

© Tokiwa Zoo, 2017


Shifting system

17. Shifting system

© Tokiwa Zoo, 2017


Floorplan of sleeping huts

18. Floorplan of sleeping huts

© Kenji Wako, edited by Jonas Homburg, 2017