It may not seem so but shooting in a zoo might turn into a totally exciting matter. "Will the picture be good despite a smudged glass, strong steel bars, frequent apathy of animals or omnipresent crowds of tourists?" Sometimes it works out well :)
My images have no specific message, but I believe that they leave some space for personal imagination and foreshadow a deeper story of animals portrayed. I also suppose that the black colour simply suits the animals and presents them in a more dignified environment than the stark walls of the enclosures do.