Marshall v. Ranne
In Marshall v. Ranne, 511 S.W.2d 255 (Tex. 1974), the Texas Supreme Court adopted section 509 of the Restatement Second of Torts, which provides that "a possessor of a domestic animal that he has reason to know has dangerous propensities abnormal to its class, is subject to liability for harm done by the animal to another although he has exercised the utmost care to prevent it from doing harm." Id.
In Marshall, the Supreme Court also recognized that even though a finding of viciousness is necessary in a strict liability claim, it is not necessary in a negligence claim. Marshall, 511 S.W.2d at 259.