This is almost as bad as the "But what if you have a gang of sixteen drug crazed lunatics that can't feel pain because if the magical drugs they are on chasing you wearing body armor and you only have a revolver?" How many crazy hypothetical situations that will likely never happen can we come up with?
No, I don't think you need to strap on your .44 mag because you are taking your family to the zoo...
EDIT: Realized that sounded harsh, no offense intended, I've just read some ridiculous hypothetical situations recently. To answer your question politely, your normal carry will be fine, as another person will be your biggest threat, and I think you might be stretching it even there to say you don't feel safe at your local zoo unless you have a gun on you. Our local zoo is pretty safe, maybe others are vastly different...