In some law schools, first year torts finals involve "Issue spotting," where the student is required to identify the legal issues raised by a hypothetical This case is a perfect example.
(A comment on Facebook disapproved of the exploitation of a human tragedy to illustrate Talmudic principles. I responded that doctors and lawyers and insurance people all use real life to illustrate and clarify the rules and principles that they need for their field. If understanding hilchos nezikin matters, then this is a perfect case, a case that involves many Gemaros in the first three perakim. I said this to my shiur yesterday, and every single person there felt that it was very helpful.)
Here are some of the questions one must address:
Is this shein, or regel, or keren? If it is keren, is it tam or mu'ad? If it is regel or shein, is this chatzer hanizik? Is someone obligated to pay kofer? If not kofer, what about regular nezikin? If someone is liable, who is it that is liable? Does it matter if the victim is a child?
If there is a chiyuv, both the Zoo owners and the attendant would be liable. The Zoo owns the animals and is obligated to watch them, and the attendant is equally obligated to do so. According to many rishonim, an owner is not absolved from chiyuv nezikin by hiring a guard- both of them are now liable.
The answer for Kofer is forthright, based on Rashi on 41b DH Veakati- there is no din of kofer by tzroros, and this is obviously tzroros.
The answer for whether it's called chatzeir hanizik is clear as well, as stated on 14a. Where both are entitled to be there, Shein and Regel are pattur and keren is chayav, like a reshus harabbim. What remains to be seen is whether it is regel or keren- this clearly is meshuneh, so it's probably not shein or regel.
Whatever motivated the elephant, it was not a desire to kill someone, so it would be like the Mishna of rubbing against a wall to relieve an itch, causing the wall to fall and kill a man. The mishna there says the animal is not executed because it did not intend to kill.
But there really isn't any nafka minah. Although we pasken like Shmuel et al, that Regel does pay Kofer, everyone agrees that oneis patters kofer. You can't have more of an oneis than an elephant throwing a stone that kills a person that's watching at a safe distance. So even if we would say that where there is no kofer there remains a chiyuv under the rules of nezikin, no such chiyuv would exist here.
So here's the new Mishna:
פיל בגן החיות שזרק את האבן, ופגע האבן בקטנה ומתה,....