By Tom Geoghegan
BBC News Magazine
A zoo in Germany has refused to help two polar bear cubs who were rejected by their mother and are now believed to have been eaten by her. So if zoos won't help to save the lives of animals, what are they for?
The time when visitors to British zoos enjoyed watching chimpanzees drink high tea has long gone.
After much soul-searching, today's zoos are no longer a showcase for exotic animals, rather places for conservation, education and interaction. But not always saving animal life, it would appear.
Despite a storm of protest a zoo in Nuremberg, Germany, has resisted helping an adult polar bear Vilma to rear her baby cubs and officials there think she may have now eaten them.
The authorities insisted nature should be allowed to take its course and were keen to avoid the kind of global publicity given to Knut, a bear hand-reared at Berlin Zoo last year.
are the largest land carnivores and live for up to 25 years
spend most of their time on Arctic ice floes
are the most likely species to kill humans for food
can smell a carcass 32km away
Knut (above) appeared on the cover of Vanity Fair
However, critics point out that "nature" can't take its course in such an artificial environment - Nuremberg is not the Arctic, after all. And Vilma's offspring would have stood no better chance of survival had they been born in the UK. The British and Irish Association of Zoos and Aquariums backs Nuremberg to the hilt - and shares the same policy.
Its director Miranda Stevenson sets out the current practice: animals are only hand-reared by humans if there is a chance they can be re-introduced to the wild as soon as possible afterwards, with their natural behaviour characteristics retained.
"Primates can be hand-reared and returned to their own species but with polar bears it is impossible because they are solitary animals and it would be impossible to re-introduce a young polar bear cub to an adult because it would be killed. The mother rears its own cubs and is programmed to kill other cubs."
Another reason not to intervene is that mothers in some species do not rear their first litter because they lack experience and don't know what to do. By going through that process - letting nature take its course - they are more likely to raise their second.
"It's a common dilemma. What zoos try to do is parent-rear. Hand-rearing isn't as obvious an option as it was 20 to 30 years ago."
There's also a practical issue of a limited amount of "good zoo space" for such big and potentially dangerous animals, she says, and while it may seem odd to let an animal within its care die, the policy is thinking what is best in the long-term.
Polar bears are very charismatic beasts and command more media attention than, say, lemurs. Such affection will only have increased since their incarnation as wise guardians in the Philip Pullman-inspired film The Golden Compass.
The UK's only polar bear, Mercedes, lives in Edinburgh Zoo. She gave birth to two cubs, in 1988 and 1991, and reared them herself before they were given to other zoos for breeding programmes.
Nuremberg's stance has surprised conservationists such as Charlotte Uhlenbroek. She is uncomfortable with polar bears being held in zoos and believes it's "mad" to say events should unfold according to nature in an enclosure so far removed from their natural habitat.
The zoo has probably learnt from experience that hand-rearing a polar bear leaves it with the question of what to do with a large, semi-tame animal, says the zoologist, because it's difficult to get captive polar bears to reproduce.
However, she thinks hand-rearing can help save very endangered species and it can work for smaller primates like lemurs going back to the wild. But there are risks.
"If they're a social animal they have to become part of a social group and being hand-reared they could forever be slightly removed from the rest of their kind which would seem rather pointless."
Professor Andrew Linzey, director of the Oxford Centre for Animal Ethics, says the real story is the plight of animals in zoos and Nuremberg is further evidence of the harm they cause.
Polar bears are mythologised
"When we've taken over their lives, made them dependent on us, and submitted them to an unnatural regime, we have a special moral responsibility for them," he says.
"The creation of dependency always involves direct duties. It's implausible to argue that just because it happens in nature, we should allow it to happen in an environment where we have artificially made them dependent on us," he adds.
"If you really like polar bears and care for them and think they are an important part of the ecosystem then help to preserve their natural habitat. Zoos actually make a minuscule contribution to conservation."
And they make polar bears neurotic, says Daniel Turner of the Born Free Foundation, which campaigns against zoos. They pace up and down their enclosures, bobbing their heads and twisting their necks, he says.
"The problem is that the zoos have been allowed to play God with the animals and they shouldn't be doing that. It should be a privilege to keep these animals and not a business.
London Zoo has changed since 1920
"Unfortunately there are zoos, and the best we can hope for is that the animals are well cared for and the public be guaranteed the zoos are going to look after them for life."
Despite a Europe-wide intensive breeding programme, few species and no polar bears are ever reintroduced to the wild from zoos.
And two macaques at Newquay Zoo were controversially put down in November because they were fighting, he says. Abroad, tigers have been known to fall into the hands of taxidermists.
Mr Turner questions how much zoos have really changed over the years.
"They've taken away the concrete and bars and put in wood and glass but the size of the enclosures is the same."
Below is a selection of your comments.
It's a self-contradictory philosophy of the zoo officials who say nature should take its course in such cases. These animals are simply not in their natural habitat and often tend to behave very differently in many cases including caring for their off-springs. It is fully the responsibility of the zoo authorities to intervene in such circumstances and save wildlife which is not actually living in the wild.
Sharad Sharma, Stuttgart, Germany
Given that the polar caps are melting and the polar bears' habitat is disappearing, endangering the species, all efforts should be made to make sure we do not lose this beautiful creature. Sometimes this means we have to interfere in the natural way of things.
Jill Gibson, Maidenhead
Zoos should exist solely for conservation purposes. They are not the natural habitat! Letting an endanger species die goes against all logic. Polar bears are solitary anyway, they don't really need to be reintroduced to a herd. Ultimately, I believe it all boils down to money and the cost of raising the cubs, later adults
Maurice, Boulder, USA
I would like to support Jerzy. Anti-zoo activists cannot have it both ways. Every since Berlin Zoo decided to hand rear Knut they have been complaining that this is unnatural and irresponsible as they now have to re-home a "tame" adult polar bear. Yet Nurnberg is being attacked for doing the opposite. I wish that we all lived in the same world as these activists seem to, but unfortunately I live in the real one where humans have left most of the earth's species on the brink of extinction. I would like my children to grow up and be able to see tigers, gorillas and polar bears alive rather than as pictures in a book and I am sorry to say the only way that this is going to be possible for most species is in zoos.
Gemma, Milton Keynes
The only argument justifying the existence of zoos, and in my view it is a fairly tenuous argument, is the conservation of certain species and the possible return of animals to the wild. This approach towards "letting nature run its course" is not only absurd (how natural is a zoo enclosure?) it negates entirely the conservation argument.
Piers Dalgarno, Belfast
Given the bears would never be released anyway, why not hand-raise them and give them to other zoos so that fewer are taken from the wild?
Mat, Sofia, Bulgaria
While I accept that zoos can do only a little to conserve natural world, I see no use whatsoever of anti-zoo activists. A year ago Berlin zoo was attacked for hand-raising a polar bear cub. Now Nurnberg zoo is attacked for not hand-raising a cub. And yes, zoos are attacked for feeding meat to their predators. Maybe zoo critics could tell how many species and habitats THEY saved?