The Mother lifted her child onto the fence as in the illustration.She was stupidly irresponsible,but why the zoo couldn't forsee this and mesh or glaze the viewing area God only knows.In picture two another observation area is partly wired.From what I can gather there is a mesh guard under the observation area...but the child bounced off this INTO the compound.
I blame both the Mother and the zoo in this case.A few years ago a child fell from a wall into a gorilla compound where luckily a silverback protected the lad from the other gorillas and he survived.A mesh fence would have avoided this too.Zoo planners worry that too much wire will spoil 'the experience' but surely low walls or fences are going to be useless as a barrier for the stupid or suicidal.
As for this earlier comment...
"I don't know the exact situation as to what happened, but surely there must've been someone around who was capable of jumping in after the kid to save him, it's not as though they are tigers or lions."
African wild dogs are much feared by lions, and single animals will run if they see a pack approaching.The Indian wild dogs (Dholes) regularly tree tigers and leopards who also have a healthy respect for them.