A peaceful haven only a short stroll from the main railway station, the ''Zolli,'' as Baselers affectionately call their small but beautiful zoological garden, has always been an imperative halt in all my visits to this medieval border town.
As a boy on long summer holidays in Switzerland, I spent several hours a day for weeks on end wandering along its tree-shaded paths, discovering its secrets, and making friends with both animals and zookeepers alike. The ''Zolli'' was never just a vast display of caged creatures, but a highly enjoyable rhapsodic adventure.
My ramblings regularly took me to different parts of its valleyed gardens. First the Shetland ponies, which I fed carefully hoarded bread crusts and carrots. Then I headed over to the old monkey house to watch the antics of the gorillas and chimpanzees as they ate their morning meal at wooden tables, clutching battered cups and spoons and acting up to the visitors like mischievous schoolchildren.
Continuing my rounds, I walked past ponds cluttered with vividly colored waterfowl from all continents to check out the Okapis in their open-air pens and then peered with expectant curiosity into the thickly foliaged bushes of the lesser panda enclosure, in the hope of catching a flicker of fur -- or perhaps even a rare, full appearance of this raccoon-like animal.
Nowadays, much has changed, although the overall magic remains. The apes still take their meals at wooden tables in good Swiss fashion, albeit in a magnificent new monkey house unobtrusively blended into the zoo's hillside surroundings. The Shetlands are still there, and so are the Okapis and the Pandas.
But new natural-looking enclosures, refurbished buildings, and relandscaped gardens have emerged in recent years. Founded in 1874, the ''Zolli'' has long established itself as one of the world's most highly rated zoological gardens with an excellent record of breeding rare animals.
Since the late '50s, the orangutans, gorillas, and chimpanzees have been producing offspring on a regular basis and are now in their second generation. Basel was the world's first zoo to breed rhinos and pigmy hippos in captivity. It was also the first in Europe to breed flamingos, whose thriving colony of pink birds and foot-high mud nests with fuzzy gray fledglings contrasts strikingly with a verdant background of plants and flowers as one enters the main gates of the zoo. Of particular note is the breeding nucleus of endangered Somali wild asses, formed in cooperation with the World Wildlife Fund.
While zoologists still find it difficult to successfully return creatures born in captivity to the wild, Basel plays an important role in furnishing other zoos with animals. Not only does this help provide the nonprofit zoo with funds, but it is also a vital conservation measure in an age when wildlife-collecting safaris are no longer feasible or ethical.
Like other progressive zoos around the world - such as San Diego or Frankfurt - Basel is not trying to maintain an indiscriminately varied assortment of animals with its 587 species. ''We have restricted ourselves to a selection of animals for which we can provide enough room for them to live and produce in families, small groups, or herds,'' explained Peter Studer, director of the zoo's recently constructed vivarium.
Despite attempts to provide the best possible living conditions for animals in captivity, the zoo recognizes that it cannot hope to fully substitute a natural environment: ''This is also not our goal,'' noted Studer. ''Our main purpose still remains recreational. A place for people to escape the noise and bustle of the outside world.'' The ''Zolli'' also doubles as a magnificent botanical garden with an impressive collection of trees, plants, and flowers.
The zoo nevertheless fulfills an important educational function, particularly for schools and universities. ''Captive animals will ultimately differ from those in the wild. Yet there is still much we can learn from them, such as feeding habits or reactions to outward changes,'' said Studer. ''We must however not kid ourselves that a fourth-generation gibbon will act the same way as one in the wild.''
Notwithstanding a shortage of funds and proper educational facilities, the zoo has already made considerable contributions to the study of certain animals, while gaining valuable veterinary experience.
As part of its concept of the modern zoo, Basel has made considerable efforts to create an environment more likely to stimulate the visitor's curiosity and imagination, while allowing one to enjoy the surroundings.
The vivarium is a good example of this. Virtually hidden by a luxurious growth of plants and bordered by water, its concrete exterior creates the impression of a thickly vegetated hill.
As one walks inside, one is immediately captivated by a multilevel aquatic world of marine and freshwater fishes in carefully-decorated tanks constructed at different angles in the walls. With each new display one is confronted by another type of environment or setting. One then gravitates to the reptiles and amphibians, ranging from Komodo dragons to Cuban boa constrictors.
''We don't want to provide everything on a platter,'' said Studer. ''The eye must be encouraged to search rather than glaze over. There must be a sense of adventure in what one sees.''