As Jeremy Hance has extremely well pointed out in his article on Mongabay of May 2014, the last few decades zoos have been paying more and more attention to nature conservation efforts. So, not just prevention of extinction by keeping species alive in captivity, but prevention of extinction in the wild. Improvements have been made in 'Zoo thinking' about conservation efforts and the contribution zoos can make to prevent the ongoing man-made 6th global mass species extinction. Nevertheless, zoos are not doing enough.
Two things in Hance's article stood out, in my opinion. Firstly, the unequal distribution of the contribution to conservation by well-respected zoos and that only a general 2% of the revenues of zoos in the US are being used for their conservation efforts. I don't know about the situation in Europe, but I expect this to be similar. Secondly, the WAZA%20Visitor%20Survey%20Report.pdf">survey that the World Association of Zoos and Aquariums (WAZA) conducted amongst zoo visitors to measure the biodiversity understanding and knowledge of actions to help protect biodiversity. The results indicate that zoos (and aquariums) can contribute to increasing the number of people who understand biodiversity and know actions they can take to help protect biodiversity. But let's not be too positive about these results because it appears that only an 8% increase of understanding could be identified amongst people after their zoo visit.