The term "common-law" merely refers to the body of law that has developed over time, from accumulating appellate court cases, dealing with specific subjects. Generally speaking, when a cases is appealed to a higher court, that higher court's ruling can have the force of law, because that higher court is interpreting what they consider to be the then current state of the law, on any particular subject. The term "common-law negligence" merely refers to the body of law that has developed over time, on the specific subject of negligence, its elements and defenses.
In order to prove a "common-law negligence" case, one must show that:
- The bite victim was in a public place, or was lawfully on the property of the owner, or the one in lawful possession of the animal; and
- That the owner, or dog-sitter had actual knowledge, before the incident, that the dog had vicious tendencies ("actual notice"); or
- That the owner, or dog-sitter had the dog long enough, before the incident, to know that the dog had vicious tendencies. If the owner or dog sitter had the dog for a long enough period of time, it would be irrelevant that he/she did not actually know; the law would say that they "should have known", by virtue of the long period of time they had the dog in their care ("constructive notice"); or
- There was some other negligent act/omission by the owner/dog-sitter, that caused the attack to occur; and
- The dog attacked; and
- Damages were sustained.