There are three rules for liability concerning domestic animals:
- A majority of states impose strict liability if an owner knows or has reason to know that a domestic animal has vicious propensities abnormal to its class.
- Generally, breed does not matter.
- If the owner does not know or have reason to know, a negligence standard is used.
- Some states set a rule by statute, often doing away with the requirement that a plaintiff prove scienter.
- (Scienter is the "knows or has reason to know" part.)