03/04/2014 12:59 BST | Updated 03/06/2014 06:59 BST

Animals Should Never Be 'Surplus to Requirements'

The storm of protest that rained down on Copenhagen Zoo following the killing and butchery of Marius, a healthy young giraffe, did not discourage its officials from announcing a few weeks later that a pride of lions - maybe even the ones to whom Marius was publicly fed - had similarly been killed...

The storm of protest that rained down on Copenhagen Zoo following the killing and butchery of Marius, a healthy young giraffe, did not discourage its officials from announcing a few weeks later that a pride of lions - maybe even the ones to whom Marius was publicly fed - had similarly been killed.

Marius was killed because he was considered surplus to requirements, genetically undesirable for the zoo's breeding programme. The four African lions - two cubs and two adults - were ostensibly euthanised to make way for a new young male lion to start a new breeding group. They too had become unnecessary. Lion cubs, it seems, are ten-a-penny in European zoos, so no suitable place for them could be found. According to the zoo the adults were simply 'too old'.

In the face of massive public outcry, zoo officials remain unrepentant. The European Association of Zoos and Aquaria (EAZA) stands resolutely behind the decisions to kill Marius and the lions, noting that Copenhagen Zoo has 'not broken any of its codes of conduct and that the zoo has been consistent in its approach to animal population management'.

Clearly not only is there something rotten in the state of Denmark, but throughout the European zoo community.

Raising public awareness

It may sound perverse coming from an animal campaigner, but perhaps we should be thanking Copenhagen Zoo. Its candour and blatant disregard for public sentiment has stimulated an important debate and raised awareness about what goes on behind the scenes in these much frequented institutions. Most other zoos would prefer us not to know, but the fact is that zoos routinely kill animals deemed surplus to requirements.

Cute sells

As EAZA has confirmed, thousands of sentient animals may lose their lives each year in Europe alone because they are considered useless for the purposes of breeding for 'conservation programmes' and/or cannot be relocated to other suitable facilities.

So why do zoos allow these animals to breed in the first place? The answer is quite simple: zoos are a business and baby animals attract more visitors. Zoo births, particularly of the most charismatic species, are often loudly trumpeted in the media to pull in the crowds. They become the latest special attraction and help zoos maximise their income.

In so doing, zoos routinely exploit what biologists have called the 'cute response'. This is a seemingly innate 'parental' reaction that humans tend to have to most baby vertebrate animals. People are attracted to baby animals who have rounder faces, bigger eyes, softer fur or feathers, shorter limbs and clumsier movements than their adult counterparts.

Yet once these animals reach maturity, they become inherently less interesting. Not only do they no longer provoke the crowd-pleasing cute response, but in practical terms - unless they have desirable genes - they will have no further role to play in the zoo's breeding programme. They may also pose a problem within their social group within the zoo, with the resulting increased and inconvenient demand on space. If there is no chance of re-homing, then a death sentence becomes the default.

Unethical practices

No animal should be deliberately bred as a crowd pleaser if that animal is likely to become surplus later on. It is both unethical and irresponsible to allow animals to reproduce in the full knowledge that their offspring will be genetically superfluous to a conservation programme, and if no other zoo has a place for them. In the case of Marius, something even more questionable was going on. Reticulated giraffes are not considered to be endangered so he wasn't bred for conservation purposes, and when the world learned that he was on death row, several institutions came forward to offer him a lifeline. So why did Copenhagen Zoo kill him anyway? Regardless of your view on zoos, for as long as animals are held in captive situations, we humans have an ethical responsibility towards them.

Planned Parenthood

There is a wide range of safe and effective contraceptive options available to zoos that should enable them to not only manage the reproduction of animals, but also allow them to live in natural family groups. It's not rocket science. If a zoo has limited space, it has no business breeding animals it cannot maintain.

Reproduction in captivity should be carefully planned and there should be close cooperation across the zoo community to ensure that animals can be re-homed when necessary. It should be possible for zoos throughout Europe, particularly those that are members of EAZA, to manage their populations without killing healthy animals.

EAZA's American and Canadian counterparts swiftly issued statements following Marius's globally publicised slaughter to emphasise that 'zoothanasia' would not happen in their accredited facilities. Their officials say their captive breeding programmes are carefully designed to manage and relocate their animals to ensure that no surplus animals are produced. Amongst other methods, they use contraceptives.

Why should it be any different here in Europe?

While the killing of Marius and the Copenhagen zoo lion family is shocking, we must hope that their callous deaths will not have been completely in vain.

The massive publicity surrounding their deaths may not only cause the public to stop and think about what happens to wild animals kept in captivity, but also to demand that the zoo industry gets its act together and stops the needless breeding when an animal's future is to be killed when he or she is no longer considered worthy.