Most courts take the position that a retail establishment is not liable for injuries caused by a pet on its premises unless there is evidence that it knew the pet posed a danger and failed to protect its customer. Whether the store possessed this knowledge depends on a variety of factors, such as:
(a) did store employees observe the pet’s demeanor prior to the incident;
(b) was the animal a type that tends to be aggressive;
(c) did the incident take place in an area of the store that was frequented by customers or was it “off-limits;” and
(d) did the store’s business cater to pets (and thus it would be more commonplace for a pet to be on the premises). 
These factors all play into a key principle of premises liability: the incident must be a probable consequence of an act or omission on behalf of the landowner.
Pet-related incidences can present in numerous ways. Businesses must be cognizant of the ways in which claims can present so that they can develop store policies addressing the potential for pets on the premises and preventing the occurrence of injury, as well as potential liability. The following is a discussion of some courts’ handling of liability for pet-related events.
The case of Andrews v. Jordan Marsh Co., 186 N.E. 71 (Mass. 1933), presents the most frequently litigated pet-related incident: a dog bite to a customer. According to the Supreme Court of Massachusetts, a department store is not liable for a dog bite to a customer where there was no evidence the store knew of the dog’s dangerousness nor were there circumstances that would have aroused suspicion about the dog. Andrews v. Jordan Marsh Co., 186 N.E. 71, 72 (Mass. 1933). It appeared that the unleashed dog came into the store with a customer; it did not exhibit any dangerous tendencies prior to the incident; and the incident took place in the basement of the store. Id. These facts meant that the store had no notice of a potential issue with the dog and was fatal for the plaintiff’s claim. The court also noted that the store did not need to take steps to determine whether the dog was dangerous because that would have been an unreasonable burden to place on it. Id. at 74.
A more recent case is that of Porto v. Petco Animal Supplies Stores, Inc., 145 A.3d 283 (Conn. App. 2016), wherein the court addressed whether a plaintiff need not prove notice of a pet’s potential for danger under the “mode of operations” theory. In that case, the plaintiff slipped and fell in a pet store on dog urine. Porto v. Petco Animal Supplies Stores, Inc., 145 A.3d 283, 285 (Conn. App. 2016). The store had a sign permitting animals into the store as long as they were on a leash. Id. The plaintiff argued she need not prove the store had notice of the urine puddle because it was liable under the mode of operations theory, which permits liability where the store’s mode of operations created an “inherently foreseeable or regularly occurring hazard,” and the incident occurred within the identifiable zone of risk. Id. at 287. Specifically, the plaintiff argued that the store’s pet-friendly mode of operation of allowing leashed pets into the store created a foreseeable risk of pet messes and that the pets were “moving” zones of risks. Id. The Appellate Court of Connecticut vehemently disagreed, finding that pet messes are not inherently foreseeable for a store’s pet-friendly business, especially since there was no evidence that the pet messes occurred regularly there. Id. at 290. Although there was certainly the potential for a pet mess to occur, the court in Porto reasoned that potential alone did not necessitate holding the store liable under the mode of operations theory. Id. The court also found no identifiable zone of risk as there was no evidence that pet messes occurred most frequently in a certain area of the store. Id. at 291. In its holding, the court emphasized the importance that the mode of operations exception be construed narrowly as almost all businesses have some risk of customer interference causing injury to another. Id. at 288.
Regardless of whether there is proof of the retail establishment’s notice of a dangerous condition on its premises (or not needing to prove same), sometimes stores may be absolved of liability by virtue of the plaintiff’s own actions. In the case of Goodwin v. E.B. Nelson Grocery Co., 132 N.E. 51 (Mass. 1921), the plaintiff was at a grocery store with her dog when it fought with the store owner’s cat. After the fight, plaintiff reached down and grabbed the cat’s paw (allegedly out of fear the cat might attack her dog again), at which time the cat scratched and bit her. Goodwin v. E.B. Nelson Grocery Co., 132 N.E. 51, 52 (Mass. 1921). The court held there was no evidence the store knew its cat was vicious and could cause injury to a customer, even though once prior the cat had “shown its teeth and pulled the fiber from the stocking of a child in the store.” Id. at 53. Further, the fact plaintiff was bit and scratched was “expected,” and due care would have been to leave a strange cat alone. Thus, in a sense, plaintiff voluntarily and unnecessarily exposed herself to danger. Id. at 52. Although not discussed in detail by the court in Goodwin, facts such as these often warrant a finding in favor of the store because the plaintiff’s own negligence in disturbing an unknown animal would have outweighed any negligence- albeit here none found- attributable to the store.
The most important lesson to be learned by our delve into this area of the law is that retail establishments need not fear they are subjecting themselves to needless liability by permitting pets on their premises. Rather, the potential liability is similar to that of any other premise liability case. A store must be aware of who (as well as what) comes onto its premises and, if there is a concern that a pet on the premise will pose a danger, that the danger must be prevented. In this regard, businesses must create store policies as to the need for vigilance in determining whether a pet poses a danger and that these policies be communicated to the staff. Also, although case law does not say that an unleashed animal, on its own, enhance a store's potential liability, to ensure there is no argument that the store failed to take proper precautions, stores should consider having a policy that any pet brought on the premises should be restrained in some fashion (i.e., by leash, carrier, cage, etc.).