225 BUILDINGS A N D EXHIBITS

exiting the building the visitors find themselves next to the entry doors, so that they experience no disorientation.

Outdoor exhibits: Outdoors there is a small penguin pool which contains a group of Black- footed penguins Sphenisctrs dernersus and some Guanay cormorants Phafacrocorax bougainvillii. Within a few weeks of their introduction, the penguins had begun to excavate nesting burrows under the hollow fibreglass rockwork and a single chick was successfully reared in 1975. Along the southeast wall of the building there is a spacious bird of prey aviary, measuring 30.5~ 7'5x75 m high, housing several species of vultures, hawks and eagles. A rockwork cliff containing planting pockets, nesting ledges, caves and a waterfall successfully conceals the building wall. The enclosure is well planted and has proved large enough to permit limited soaring. An aviary for native birds is located on the south wall, and there is also a grassy yard for a pair of cassowaries Casuaritrs casuarius, with indoor quarters inside the building, on the southwest corner.

In addition to the kitchen previously mentioned, service facilities include two holding areas, an incubation room, a brooder room, and a locker-toilet room for the keepers. There is also a curatorial ofice. An auxilliary generator building is provided so that mechanical service can be continuous in the event of a power failure.

CONCLUSION

Bird World has now been operational for more than a year and can be reviewed critically. Problems have been minimal and not insur- mountable. Our chef concerns have centred around the mechanical equipment necessary to heat and air-condition the building and structural insufficiencies which caused extensive leakage in the Theme Hall's mountain stream exhibit. The latter had to be completely reworked. Three aspects of the project have proved most reward- ing. The reaction of zoo visitors has been highly positive and encourages us to create additional naturalistic exhibits of similar concept. In the main, the tropical plantings have thrived and the result has been a superb botanical display of great educational value. The bird collection has done very well and has exceeded our highest hopes. Besides the Black-footed penguin, species whch bred successfully in Bird World during its first year are Blue-crowned motmot Momotus momota, Red-crested cardinal, Black crake, Ringed teal, Mountain bluebird, Bali mynah and Malayan crested wood partridge.

SUPPLIERS M E N T I O N E D I N THE TEXT Artificial rockwork and watercourses: produced by the Julian George Corporation, Los Angeles, California, USA. Graphic information panels: produced by The Exhibigraphics Group, Salt Lake City, Utah, USA.

Manuscript submitted 6 April 1976

Tropical House for Apes at Krefeld Zoo [Plates 52-54]

PAUL VOGT Assistant Director, Kr@fd Zoo, 415 Kr@ld, Uerdinger Strasse 377, West Germany

The new Ape House at Krefeld Zoo, donated by a local citizen at a cost of 21 million DM, was designed to provide an open-plan exhlbit with climatic conditions similar to those of the tropical rain forest. To achieve this in the temperate latitude of Krefeld, the archtect, Dipl. Ing. K. Meywald, conceived the idea of surrounding the

entire complex with a large glass house, measur- ing 30x 65 m in area and 11 m high at its apex.

H E A T I N G

Temperature control in such a structure was expected to present a problem and in the first year of its use the building had to withstand

226 BUILDINGS AND EXHIBITS

extreme climatic conditions. For several weeks in the summer there were exceptionally high temperatures and during the winter there was an unusually cold period. In addition, severe storm occurred at the beginning of the year.

In fact, temperatures of c.2ooc were easily maintained with conventional greenhouse heating (convector and pipes running under the roof) plus thermostat-controlled warm air blowers, installed under the roof, for use in frosty weather. The main problem is to prevent the temperature rising above the acceptable maximum ( 3 0 " ~ ) on hot sunny days and roller blinds are fitted to shade the glass roof as necessary. Large windows give good ventilation and three large skylights, measuring 8X 6.5 m, above the main animal enclosurescan be opened in fine weather to give the animals the benefit of direct sunlight. Ultra-violet fluorescent lamps are installed for use in winter.

The following examples give some indication of the range of temperatures encountered and the control possible w i h the budding: Sutnrner (6 August 1975): sunny outside temperature 17.5-38"c range 20-5Oc inside: upper level 28.5-36.3'~ range 8"c

lower level (animal area) 28.5-29.5"c range I'C

Winter (29 January 1976): sunny outside temperature - I Z - ~ - O ' ~ ~ C range 13Oc inside: upper level I Y ~ - Z ~ . ~ ~ C range 7Oc

lower level (animalarea) 1 ~ s - 2 0 ' 5 " ~ range I'C

PLANTING

The dense tropical vegetation, which is watered with specially collected rain water, maintains a relative humidity which varies between 65-95 % but is usually in the region of 75%. The choice of plants was influenced not only by the necessity for species which would withstand changes in temperature and humidity but also by the requirement that they should be pest-resistent. In the vicinity of the enclosures, pest control was ruled out because of the possibility that shoots and leaves might be picked and eaten by the animals.

The species m a d y used were Ficus benjamini, Ficus pandurata, Ficus elastica, Scheflera, Philo- dendrotl, Monstera, Tetrastigma voinerianum, Cissus, Musa, Hibiscus, Codiaeum variegatum, Phoenix dactylifera, Kentia.

ANIMAL ENCLOSURES

The exhibition area consists of four enclosures, separated from the public by dry moats or 36

L

Fig. I. Ground plan of Ape House, Krefeld Zoo. A. exit. B. lever, hydraulic doors. CH. chimpanzee enclosure and sleeping dens. E. entrance. G. gorilla endosure and sleeping dens. K. kitchen. 0. orang- utan enclosures and sleeping dens. P. keepers' entrance. PW. service path. T. pond. V. visitors' path. W. cages for babies or monkeys. Z. cistern.

BUILDINGS AND EXHIBITS 227

mm-thick glass windows, and two glass-fronted cages which can be used for small monkeys or as nursery quarters for young apes. They are viewed from a walkway 155 m long, which can accom- modate up to 1000 people, affording a good view of the exhibits to 750 visitors at any one time. A one-way system is in operation.

Behind the public enclosures are the sleeping dens and the service area, containing a kitchen and nursery, store room and keepers' room (Fig. I).

At present the animals housed are 1.5 West African chimpanzees Pan troglodytes (3-5 years old); 1.3 Lowland gorillas Gorilla g. gorilla (3-5 years old) ; and 1.3 Bornean orang-utans Pongo p. pygmaeus (9-1s years). The two cages on public exhibit contain a group of Purple-faced langurs Plesbytis senex and a group of juvenile siamangs Symphalangus syndactybs.

The chimpanzee enclosure, covering 147 m2 and the gorilla enclosure 108m2, have moats 3.5 m deep and 45 m wide and the two orang- utan enclosures have areas of 8 6 m2 and 96 m2 with moats 3.0 m deep and 3.5 m wide. All are surrounded with plant troughs 3-5 m high. The walls and floors are covered with colourless epoxy resin which facilitates cleaning and also helps to protect the animals' pelts from rubbing by the rough surface. The floor has an orange

peel fd to prevent the animals slipping. Underfloor heating conduits c.1.2 m wide and heated to 4 5 ' ~ run along the back wall between the enclosures and the inner dens giving a floor temperature of c. 25'c.

The enclosures and exhibition cages are equipped accordmg to the needs of the species. Natural trees, up to 5 m high, protected and strengthened with fibre glass and polyester, provide climbing facilities. There are also climb- ing ropes, hammocks and rubber cables and nesting materials, such as twigs and wood wool, and dried leaves, sand and water are provided for play. In the gorilla enclosure large rocks offer the opportunity to climb and hde and pieces of 'iron-wood' (kambala) cover climbing poles, where the apes llke to hide themselves and to drum. Each enclosure contains a b a h g pool but with young chimpanzees and gorillas these can be left filled for only short periods or the animals will play in the water for too long.

The sliding doors to and between the back dens are hydradcdy operated and since they are positioned so that they can be easily seen by the keepers, separation of the animals when necessary has not proved difficult.

The 16 sleeping dens (three each for chimpan- zees and gorillas, four for orang-utans and six for small monkeys) have a total area of 120 m2 and

Fig. 2. Section through orang-utan exhibit O1. A. sliding door. B. plant trough. C. climbing tree. I). visitors' path. E. iron-wood (kambala). F. skylight.

228 BUILDINGS AND EXHIBITS

are 2’ 8 m high. They can also be used as isolation or sick dens or maternity quarters and are equipped with climbing bars, ropes and resting platforms. As they have grilles at the top and along the service passage, there is a free exchange of air within the cntirc building and daylight also reaches all the inner cages.

Up to the present no unforeseen problems have been encountered. The nlinimum distance of 5 m between public and animals reduces the dangr of cross-infection and the animals are

vaccinated against tuberculosis and poliomyelitis to guard as far as possible against these diseases.

The still young chimpanzees and gorillas settled into the new quarters without dfiiculty. The adult orang-utans, which had previously lived in temporary quarters behind glass, were somewhat shy at first but have settled well. Breeding activity has already been observed among the orang-utans.

Manuscript submitted 16 May 1976

Brown rat Raftrrs rrorvtgictrs [Plates 59 & 601

exhibit at Copenhagen Zoo PER SEATON St~peririt~rident of Brtildings and Grounds, Copetikagcrz Zoo , 2000 Copenhagen F, Denmark

Living as it does in the subterranean sewers of the large city, the domestic Brown rat Rattits rzorvqicirr is not, despite its vast numbers, a common sight and provides little opportunity for observation in its chosen habitat. It was this that prompted the idea of displaying the animal in its ‘natural’ surroundings. In the spring of 1974, we niadc a preliminary tour of inspection of the sewers of Copenhagen, and our impressions formed the basis of plans for an exhibit which was to make it possible for the zoo visitor to look directly into a cut-away section of sewer tunneland to watch therats behaving as they might do had they remained hidden from human eyes.

With animals such as these it is a basic pre- caution to ensure that the exhlbit is escape-proof, and to this end the sewer tunnel has been con- structed out of iron sheeting, 4 m m thick. The sheeting is rolled into the shape of a large C and welded together for its full length of 7 m; its diameter is 1.2 m. At either extremity there is a chamber, one for feeding and the other for breeding, which is an incentive for the rats to run up and down the tunnel with greater frequency. Water, circulated by an electric pump, covers the sewer floor and, as extra touches of realism, the interior surface is cement coated and there are several outlet pipes in the

background. Loose pieces of broken pipe, cloth- ing and other items such as might be found in a real sewer are scattered about (Plate 59).

The sewer has been installed in a former storage cellar, a location whose exhibition potential would otherwise have been wasted. Rats as a rule being nocturnal animals, they have here been displayed under reversed lighting conditions. It seems, however, as if this might well be un- necessary because even under full light they are extremely active. On the other hand, the daytime gloom in the exhibit does create a distinctly dramatic effect, and this is further accentuated by the darkly painted walls and dim lighting of its surroundings. The illumination of the sewer is only slightly brighter than that of the sur- rounding public area and the total impression that it generates is one of calculated unpleasant- ness (Plate 60).

The visitor views the rats through windows situated at intervals along the tunnel section, while above the breeding and feeding chambers concave, dome-shaped acryllic skylights invite him to put his head, as it were, right inside the installation and survey it from the interior. These skylights have been placed at different height levels to give small children the same viewing advantage as adults.