When a person’s property causes damage, obviously there is a need to pay restitution. Nevertheless, the Torah teaches that we distinguish between a shor mu’ad – an ox that has gored in the past – for which one pays full damages (nezek shalem), and a shor tam – an ox with no violent history – for which one pays for only half of the damage (hatzi nezek) that he caused.
Our Gemara explains that Rav Pappa and Rav Huna, son of Rav Yehoshua offer different approaches to the law of hatzi nezek. According to Rav Pappa, every ox is potentially dangerous and the owner really should pay full damages. Since this is a “first offense,” however, the Torah is lenient with him, and only obligates him to pay half of what he owes. Rav Huna believes that an ox that never showed any indication of violence does not need to be watched carefully, and because its behavior was unusual, its owner should not be obligated to pay any damages, at all. Nevertheless, the Torah imposed a penalty – a kenas – on the individual so that he should make sure to be more careful in the future.
The Gemara concludes that we follow Rav Huna’s opinion, and rule that hatzi nezek is a kenas. This leads to an interesting ruling. Unlike standard monetary rulings which are entrusted to all Jewish courts, penalties can only be applied by properly ordained judges. Since ordination was only given in the Land of Israel, cases involving kenas were not heard in Babylon. Thus the Gemara concludes that unusual cases of damage – like a dog eating a lamb or a cat eating a large chicken – would not be tried in Bavel.
From stories that appear in the Talmud it would seem that during those times cats were not fully domesticated. Although people did keep cats in their homes to protect the inhabitants from rats and snakes, it was fairly common to hear of a cat that attacked domesticated birds and even babies in the house. Similarly, dogs were not kept as pets, rather they were guard dogs or used for shepherding. The cases mentioned in our Gemara are unusual specifically because the animals that were attacked were larger than normal.