Equality, peace and rights are so important. Different color, religion, gender, sexual orientation, or any other criteria, are all irrelevant for us granting everyone equality, peace, nonviolence and rights. Not only among humans, but among all species. In fact the unequality, violence and suffering that we inflict upon other species, and the justification of this unequality and violence based on this artificial and irrelevant criteria, is the root of the violence, suffering, and unequality in our culture. As we sow, we will reap.
"Fourth, as I argued in my chapter in The Great Ape Project and as I have said repeatedly since then, the right to full membership in the moral community and the right not to be treated as property is dependent on only one characteristic—sentience. If a nonhuman is sentient, then we have a moral obligation not to treat that being as a resource or commodity. The fact that a dog may not have the same sort of reflective self-awareness that a chimpanzee has does not mean that the dog and the chimpanzee are not equal for the purpose of not having their fundamental interests in life and in not suffering disregarded if it benefits someone else to do so.
Animals are killed everyday at zoos (and many, many other places) for a variety of reasons. The shooting of poor Johnny was surely tragic, but equally so are those deaths of nonhumans who are not “similar” to us in the way that Johnny was, beyond being creatures who had subjective awareness and who valued their lives in their own ways.
Go vegan, never patronize zoos, and resist the creation of new hierarchies based on anthropocentric values.
Humans are not the measure of things; we are only one measure among many.
I also recommend this wonderful lecture by Will Tuttle: http://www.youtube.com/watch?v=SvZpF1R6GUo