Bava Kamma 35: The Burden of Proof

Cases of damage by the animal vs a person - where the question of who is liable that can be less pleasing to the person who has suffered damage, and might not get paid back. Specifically, when does a person's intent make a difference with regard to paying damages (or getting paid for them)? Plus, a new mishnah: One ox chases another ox, which is subsequently damaged, and the owner blames the other ox, but that ox's owner claims the damage took place in some other way. Who wins? The one seeking payment has to prove his case. Another case: two oxen chasing two oxen, of different sizes. How to identify which damaged which? Which is tam vs mu'ad, etc.? The Gemara puts all of this in the context of Sumchos' view that any dispute is solved by dividing the property.