Never mind the animals. Can ourzoos save themselves?

They have come a long way since the days of chimps' tea parties, and are now on the front line of the worldwide conservation battle. But the public's growing interest in animal rights means that to survive, zoos will have to become very different beasts

A quarter of all the birds in the world have become extinct over the past 200 years. Almost all large wild mammals are threatened: 90 per cent of black rhinos have been killed in the last 18 years, more than a million metric tons of animals, mainly primates, are slaughtered yearly as bushmeat in tropical Africa. We hear almost daily reports of the natural world going awry: of coral bleaching, infectious plagues in pearl oysters, unusual phytoplankton blooms, peat bogs petering out, dry wetlands and wet drylands, fish cancer and female frogs that once were male. At present rates of deforestation, the last tropical evergreen tree will fall before 2045.

With such an endless catalogue of destruction, it seems almost impossible to believe that keeping wild animals locked up can do any good. But could zoos play a role in helping to protect our fragile wilderness and its wild animals in the 21st century? Zoos have changed from places of entertainment where visitors went to gawp at exotic animals to conservation-oriented institutions intent on breeding and reintroducing animals into the wild and providing "infotainment" - an amalgam of education and fun.

"We've made it clear that conservation is our raison d'être," says Dr Jo Gipps, director of London Zoo. "People come to us for a brilliant day out, but it's an educative experience." Only 30 years ago we were watching chimp tea parties, now Wildcams are hooked up to the internet allowing anyone with a computer to spy live on gorillas, hippos and flamingos in Washington Zoo.

Dr William Conway, of the Wildlife Conservation Society, New York, said in his address to the World Zoo Organisation last autumn: "To survive and fulfill their obligations to society, [zoos] must become proactive conservation organisations, not living museums, and they must do it now." This dramatic shift in social attitude has forced zoos to embrace conservation ideals, but can an institution that enslaves animals be any good at setting them free?

One of the most highly publicised conservation goals zoos have taken part in is the breeding of endangered species and their reintroduction into the wild. The re-release of golden lion tamarins is estimated to have initially cost more than $20,000 per animal. "Reintroduction programmes are in their infancy," says Dr Gipps. "They're expensive and they're limited. No one has introduced a big cat, for instance, and in many cases we must not and cannot introduce animals for the sake of it."

Simon Garrett, who is the head of education at Bristol Zoo is sceptical of some of the claims that are made about the success of reintroducing

animals. "Personally I'm amazed that any reintroductions work given the state the planet is in. It's not ethical to put animals back into the wild when they could be shot, poached or eat people."

As small as a squirrel, golden lion tamarins are hardly likely to eat anyone, and despite the expense and loss of some of the animals, according to Dr Gipps, they are one of the most successful examples of reintroduction programmes.

Although reintroductions are few and far between, Dr Gipps argues that raising the profile of one charismatic species can save others. If the habitat is conserved for that species, and local people made aware of its needs, then other animals within the environment will also be saved. By concentrating on these "flagship" animals, zoos do not need to become like Noah's Ark and save everything.

But if conservation programmes such as these are to work, then zoos will have to move out of the cage and into the field, not only conserving land, but also helping local people. In the future, zoos could be proactive enough to design and recreate whole habitats. Bristol Zoo is currently working with the local people of the Comoro Islands in the Indian Ocean to preserve the last remaining 400 fruit bats on the islands. It is also aligned to the Cameroon Wildlife Aid Fund to try to raise awareness about the bushmeat trade in central Africa.

Many zoos argue that even if they have no intention of introducing animals back to the wild, it is important for them to continue to breed endangered species. A number of species will become extinct over the next few years and zoos can act as "reservoirs" of animals preserved solely in captivity but which could then be released - if there is any wilderness left.

Human population growth has slowed, but nearly a billion people are added to the population every 12 to 13 years. "When the population is stable we'll work out what's left and what to do," says Dr Gipps. "The rate of destruction is so great the world will look very different." He believes we will have lost most of our big animals, such as the mountain gorillas of war-ravaged Rwanda, a particularly unsafe area for man and beast alike. Their numbers have dwindled to fewer than 200. "I wouldn't put your savings on mountain gorillas surviving until 2050," says Dr Gipps. There are no mountain gorillas in captivity; if there were and should the gorilla become extinct, it might be possible to reintroduce them. This was successfully done with the black-footed ferret when only 15 animals remained in the wild.

To facilitate the breeding of endangered species, zoos have started to freeze eggs, sperm and even fertilised embryos. Dr Bill Holt, the acting director of science at the Institute of Zoology, in London, says that the institute's research is part of an on-going programme and not yet at the stage of a viable gene bank that could be used to support practical conservation efforts. However, sperm from giant pandas will be given to China as part of their endangered species programme, and the institute has already helped Spain reintroduce the Mohor gazelle to Morocco by providing and storing gazelle sperm.

In spite of all these laudable aims, is it even ethical to keep animals in captivity in this day and age? After all, wildlife films are of a high calibre and the internet combined with CD-roms provides digital images of many species. Yet Simon Garrett believes zoos still have a role to play: "I was watching Life in the Freezer the other day, and the bull elephants are enormous, but you don't get that from the film. You can't see, hear, or smell animals for real. The role of zoos should be to let people see them up close and make an urban-based population empathic with nature."

Dr Robert Garner, from the University of Leicester, is the author of Animals, Politics and Morality. He says that whether zoos are a good thing or not depends on your ideological predisposition. "From a strict animal-rights perspective, zoos are morally illegitimate as they deprive animals of freedom. Personally, I think zoos are justified if the needs of the animal are met and this has to be independent of entertainment and conservation. This rules out keeping some animals in zoos, such as polar bears, which travel huge areas in the wild." Dr Garner says that this means there can be a discrepancy between the needs of an individual animal and the conservation of the species.

Arguments about the ethics of keeping wild animals locked up, even for the benefit of their species, are not going to go away. Dr Gipps is more familiar than most with the continuing debate. "Some people believe zoos are simply wrong. It's a point of view I can't argue with if it's held strongly. But if you accept zoos as a concept, then it becomes the welfare of those individual animals that is important - you've got to keep an animal in good condition even if it's rare and part of a breeding programme." An animal in good condition is more likely to breed and an animal that is breeding is usually content.

So what will the zoos of the future be like? One idea is the "At Bristol" concept. It is an almost animal-free zoo; when it opens it will have a library of film footage of endangered species as well as an on-line resource. There will also be an electronic hide using high definition TV with live footage of wild animals, such as a seabird colony. "What is acceptable now won't be acceptable in 30 years time," says Dr Gipps. He accepts there will be changes but emphasises the need for zoos to continue to act as a reservoir of endangered species. London Zoo is aiming to breed and create a gene bank that will preserve 95 per cent of a species' genetic diversity over the course of 100 years. "This shows we're in it for the long haul," Dr Gipps says.

History shows that zoos need to change as public attitudes towards caged animals also change. Zoos also need to take into account new developments in the technology of conservation and breeding. Just as the zoos of 100 years ago are viewed as barbaric places by today's sophisticated public, then zoos of today may find themselves unpopular and outdated if they fail to address growing concerns about wildlife protection and animal husbandry.

Dr Conway sees zoos as vital elements in the continuing battle to preserve what is left of life on earth. "The 21st-century zoo must be redesigned as a hedge against biological impoverishment; a time-machine buying continuance for faltering wildlife populations; a corridor of care between park and reserves; and, more than ever, humanity's primary introduction to wildlife, promoter of environmental literacy and recruiting centre for conservationists."

Zoos may not stop the drastic destruction of wild animals, but they could at least help to protect some species from being totally lost.