Is there any justification for keeping animals, living beings, in strict captivity? A question that creates debate right at the moment of posing it. Many people have strong feelings against keeping animals in captivity, and would like to ban the concept of “Zoos”. Others don't give it any attention as long as they are entertained when visiting the Zoo.
The mission of well-respected Zoos, those accredited as members of the global zoological association (WAZA) and/or regional associations such as EAZA, AZA and ZAA, officially addresses conservation, research, education and recreation. The first two with regard to ecosystems and (endangered) animal species, and the latter two aiming at the Zoos' visitors.
Since recreation means for the average visitor that he wants to have a good time when visiting the Zoo, this is a caveat that Zoos have to deal with. To get the message across about the peril situation of Planet Earth, the need for better protection of ecosystems and saving endangered species, together with better understanding of these ecosystems and species, education is the perfect instrument of course.
For children the recreational part (entertainment) can support the more serious aspects of the Zoos' mission. In other words, learning can be made fun. And many Zoos have succeeded in developing entertainment/education programmes for children that incorporates the serious message there is to tell. Whether or not this message is about to stay after the visit to the Zoo (do children increase their knowledge in a sustainable manner?) is under debate. Dr Eric Jensen has published an interesting report in 2011 on the evaluation of the educational impact of the ZSL London Zoo formal learning programme. Regarding the debate on the impact of educational instruments of Zoos this PLOS Sci-Ed blog is a must read, especially the comments. 
Let's not linger on the entertainment and education of children in Zoos too long, because many Zoos have established excellent ways to attract children's attention, including education programmes for the young. But what about the adults, the parents and grand-parents that want to be educated beyond the basic information their (grand-)children are provided with. Not all adults settle for some of those colourful cartoonish Zoo websites or information leaflets, nor settle for brief information. Adults shouldn't even settle for the mere message that humankind is destroying ecosystems and forcing species to the brink of extinction. They should be provided with background information and solutions about how they can contribute to decrease their impact on Planet Earth's impaired situation. For example, when they want to save orangutans in Borneo which is caused by the extensive logging, Zoos should provide a blacklist of tropical woods that people should avoid purchasing. Or, when being explained that climate change is disrupting ecosystems, it should be accompanied by the message that we are causing the current climate change and how we can do something about it (use less fossil fuels, etcetera).
This is where Zoos can influence people's attitude. This even justifies that some specimens of (endangered) species are kept in captivity to help raising awareness on the peril situation of ecosystems and the world we live in. Provided the enclosures are state-of-the-art, and animal welfare is ensured by meeting the freedoms from hunger and thirst, from discomfort, from pain, injury and disease, from fear and distress, and to express natural behaviour (Brambell's five freedoms, originally developed for farm animals but became ubiquitous in the assessment of welfare for all animals, including those kept in zoos).
A more comprehensive and visualised presentation of my personal view about the importance of Zoos and the justification for their existence can be watched below:
Of course, there are Zoos which are able to provide information as requested by interested visitors. For example by well educated volunteers that can answer many question, or by leaflets with extensive information on the Zoo's contribution in conservation programmes. But how many of these Zoos do you know?
Let's be clear about this. When Zoos take their mission seriously, which is a very mature mission, they should take all adult visitors seriously, and address them with dedicated and targeted information that suit both the needs of the Zoo and the visitor. Do not get me wrong, I like to see children enjoy themselves with entertainment programmes while at the same time being taught important things about nature, but Zoos should give due consideration to the required level of information for adults too. Adults are not children, and they influence the world now, while the impact of children on Planet Earth can only be expected in due course!
(Source: Life is Good (chapter 8) by Jeremy Leon Hance, 2012; PLOS-blogs Sci-Ed; Academia.edu; Zoo Animal by Geoff Hosey, Vicky Melfi, Sheila Pankhurst, 2009; Wikipedia)
