Excellent, well written article. However putting things in perspective it could be say that accident happen as a result of negligence on both the mother and the zoo employees. The duty of care lies on both, where mother responsibility to ensure the child dos not cross the safety barriers and the zoo staff to take every precaution possible for that not to happen. Having said that, zoo is manage by human being and we human make mistakes.
Why not sedate the animal rather than kill it? Is a question I would like to ask.