Bava Kamma 21: More Animal Behaviour

The rabbis discuss the differences between a house that is lived in and safeguarded and a house that has been left empty.  I wonder about squatters in the times of the Talmud.  Were there people who were homeless, perhaps those without family and its protection, who would find empty courtyards and buildings to live in?  Would these be the same people who collected food from pe'a?  Were the rabbis attempting to create a social safety net for those at greatest risk without imposing upon those who would make money from their spaces - is that why they seem to insist that an unused courtyard/home not intended for renting is permitted for squatting?

We are told the story of Rav Nachman's confiscation of a mansion. The mansion was built atop a garbage heap used by orphans.  The orphans were paid by Carmanian people who also used that land.  When the orphans were evicted for the building of that mansion, they lost their income. Rav Nachman confiscated the mansion from its owner when he refused to recompense the orphans for their loss.

The Gemara wonders when an animal's actions in the public domain create a situation where damages should be paid.  What if a cow is in the public domain but turns its head to eat from someone's private domain?  Does it matter where the body of the cow is placed?  Should we be considering the damage done by the cow or the benefit derived by the cow?  Or both?

A new Mishna tells us that the owner of a dog or a goat who jump from a rooftop and break a vessel is responsible for full damages, for animals are considered forewarned regarding jumping.  If a dog grabs a cake hot from the oven with a coal stuck to it and takes it to a stack of grain to eat it, igniting the grain, the animal's owner is liable to pay full damages for the cake and half damages for the destroyed grain.

Why is the owner of an animal that jumps from a roof liable to pay damages? Because this is typical behaviour, and the owner's neglect led to this accident.  If a dog or a goat jump from below up to something and break a vessel, the owner is not liable because this is unusual behaviour.