Text A: The modern ark

[1] The word 'zoo' still conjures cramped cages and pacing tigers, but the best modern zoos have left that grim picture far behind. Today they describe themselves, not unreasonably, as arks: places that keep a species afloat while the storm of habitat loss rages outside. When the last wild individuals of an animal vanish — as they have for several species in living memory — it is sometimes only a zoo population that stands between that creature and the void. To shut those doors, the argument runs, would be to drown the passengers in order to protest against the flood. The best of these institutions, their defenders insist, are no longer menageries built for our amusement but serious centres of science, conservation and education, and to judge them by the cramped, cruel zoos of the past is neither fair nor honest.

[2] The successes are real and specific. Animals that were declared extinct in the wild have been bred behind glass and, years later, released back into restored habitats, where their descendants now run free; a visitor to certain forests and grasslands today is looking at animals that exist only because a zoo refused to let them go. None of this is cheap or easy. It demands decades of patient science, meticulous record-keeping, and international cooperation between institutions that lend and share their animals rather than hoarding them. A single zoo cannot save a species, but a network of them, pooling knowledge and breeding stock across continents, sometimes can — and has.

[3] Zoos argue, too, that they quietly change the people who walk through their gates. A child who meets an elephant's eye, who feels the ground tremble under its feet, carries away something no documentary on a flat screen can give: a sudden, physical understanding that the animal is real, vast, and worth protecting. Millions of such visitors fund conservation projects in the wild with nothing more than the price of a ticket, and a surprising number of the scientists now fighting to save wild places will tell you that their life's work began on a single, ordinary childhood afternoon at a zoo.

Text B: A beautiful prison

[4] However gently it is decorated, a cage is still a cage. Critics point out that a great many zoo animals show what scientists call 'stereotypic' behaviour — the endless pacing, the rhythmic head-swaying, the obsessive over-grooming — that researchers recognise as the unmistakable signature of a mind under strain. An enclosure that looks like a generous slice of savannah to a passing visitor is, to a creature built to roam fifty kilometres in a day, merely a comfortable cell, and no amount of artful landscaping or painted backdrop changes its true dimensions.

[5] The conservation argument, opponents add, is far thinner than the zoos like to imply. The overwhelming majority of animals behind the glass belong to species that are in no danger whatever; they are there because they are popular and reliably draw a paying crowd, not because anyone is saving them. The handful of genuine reintroduction successes, real and admirable as they are, is utterly dwarfed by the number of animals living out their entire lives purely as exhibits. A polar bear, the critics say flatly, is not rescued by being displayed to schoolchildren in a hot country thousands of miles from any ice.

[6] As for education, the opponents are blunt about what is really being taught. The lesson a child absorbs at a zoo, they argue, is not reverence for wildlife but the quiet assumption that it is perfectly acceptable to keep a wild animal in a box for our amusement. And the money — the vast sums spent building, heating, staffing and insuring these collections — would, they insist, protect far more creatures if it were poured instead into the wild places those animals were taken from. Save the forest, they say, and you save everything that lives in it, from the tiger to the insect, without imprisoning a single creature to do it.