This surely was not a 'first time' for these teens who found such pleasure in mistreating an animal.
I remember one at FW who had a very bad temper, if you even looked at him wrong he would get pissed, jump around, then beat on the glass till you thought he would break through and go on a king kong rampage.
Another female chimp used to enjoy eating her own feces in front of the crowds, they finally got rid of her. (she went on to be 1st lady in the 90s)
This article makes it sound like the teens were stoning this gorilla like a group of palestinians would like to do to do Sharon right now.I am not buying that at all.
I think the zoo staff and city are trying to pass blame from their cage building incompetence and lesson their risk of a law suit from the injured.
Here is an idea, build a cage dangerous animals cant escape from, and that unruly teens cant throw objects into..