The Cincinnati police have investigated the incident and determined that no charges will be brought against the mother or the zoo. I believe that this is most likely the correct decision, as they have interviewed all of the witnesses and checked the barriers.
I do have some lingering concerns. The design at the great ape exhibit in Cincinnati was a great leap forward in design, and has been used as the prototype for large animal enclosures worldwide, including here at Zoo Atlanta (Jon Coe used some of these basic immersion concepts, including barrier design, at Woodland Park and then here). The basic design, a 36-42 inch railing or fence facing the guests, followed by about four to six feet of dense shub barrier and a 2-3 foot tall stub wall facing the crowd, which is actually the top of about a 20 foot sheer wall on the animal side. Some modifications have included a low metal fence concealed within the shrubbery, but it doesn't appear that Cincinnati had this at that particular enclosure. The barrier is designed to first and foremost keep the animal inside the enclosure while offering an unobstructed view of nearly all of the habitable enclosure. Secondarily it is to present an obstacle to discourage the overly curious, both young and old, from trying to get a closer look. In broad general terms, the brush is so dense that it should be uncomfortable at best to approach beyond the railing, and the twenty foot drop on the back side should be daunting for even a toddler who is old enough to make it that far in the first place.
In almost 50 years of this design being in use, I cannot recall but two or three instances of a young child getting across, and a handful of (usually drunk) adults doing the same. However, this is a zoo, not a prison, and it must be assumed that the guest assumes some responsibility for their own safety and the safety of their children. There are signs all over the grounds warning parents to watch their kids closely, but as was brought up kids are kids. The question now becomes how "impenetrable" should a wild animal enclosure be from the guest side? What if anything can be done to make them safer without a gigantic investment in remodeling, and what would be the advantage if any? Can any reasonable modification keep a determined four year old from doing the seemingly unthinkable? I'm sure we will hear more about these questions after the lawyers arrive.
