Until the 1980s, courts did not create or sanction different rules of law for different breeds of dog. Except for statutes that modified the common law's "one bite rule" (see The One Bite Rule), general principles of law were applied to all dogs more or less regardless of breed. These principles are contained in the Restatement of the Law of Torts, Second, and are summarized in other authoritative works, such as American Jurisprudence. It was stated in 4 Am. Jur. 2d Animals § 86, 90 (1962):

The owner or keeper of a domestic animal is bound to take notice of the general propensities of the class to which it belongs, and also of any particular propensities peculiar to the animal itself of which he has knowledge or is put on notice; and insofar as such propensities are of a nature likely to cause injury he must exercise reasonable care to guard against them and to prevent injuries which are reasonably to be anticipated from them. . . .

Even in the absence of any known viciousness in a domestic animal, its owner is obliged to exercise over it a certain degree of care depending upon the kind and character of the particular animal concerned, the circumstances in which it is placed, and the purposes for which it is employed or kept. The owner or keeper of a domestic animal is charged with knowledge of the natural propensities of animals of the particular class to which this animal belongs, and, if these propensities are of the kind that might cause injury he must exercise the care necessary to prevent such injuries as may be anticipated.

The 1980s saw a change in how the courts applied the foregoing general principles, as well as a number of rulings that were explicitly breed specific. No longer was a dog considered dangerous simply for behaving in a vicious or dangerous manner. New rules, both criminal and civil, were created for pit bulls because this breed became involved in a disproportionately high number of attacks upon people. (See Statistics.)

In a criminal prosecution, if the defendant is accused of assault or another crime in which a pit bull was used as a weapon, the courts always rule that the defendant had knowledge that the dog was vicious simply because of its breed, as opposed to its prior behavior. Pit bull dogs have even been considered weapons. See State v. Livingston, 420 N.W.2d 223, 230 (Minn. Ct. App. 1988) (for the purpose of first degree assault); People v. Garraway, 187 A.D.2d 761, 589 N.Y.S.2d 942 (1992) (upholding conviction of pit bull's owner of criminal possession of a weapon in the third degree). In People v. Nealis (1991) 232 Cal.App.3d Supp. 1, the dog was commanded to attack, so the court held that the dog was a deadly weapon. In People v. Henderson (1999) 76 Cal.App.4th 453, pit bulls were used to threaten police, so the court held that the dogs were deadly weapons, not necessarily because of their breed, but because the defendant was using them as such.

In a civil lawsuit, if the defendant is a pit bull owner and the dog has bitten a person, some (but not all) courts hold that the fact that the dog was a pit bull can be used to prove knowledge of viciousness even if the dog never before acted ferocious to people or bit another person. For example, in Edgar v. Riley, 725 So.2d 982 (Ala.Civ.App. 1998), the owners of a pit bull were deemed to be aware of its dangerous propensity to attack without warning, even though it never had done so in the past, thereby supporting a jury's finding of civil liability for a dog bite. However, many courts refuse to allow a jury to use the breed of dog as a basis for finding that the dog's owner knew it was vicious if the dog had never behaved viciously in the past.

Court decisions have included a wide variety of negative findings and remarks about pit bulls:

  • "The extreme dangerousness of this breed, as it has evolved today, is well recognized." Matthews v. Amberwood Associates Limited Partnership Inc., 351 Md. 544, 719 A.2d 119 (Md. 10/07/1998)
  • The pit bull is "a breed of dog that has achieved a remarkable notoriety for aggressiveness." Gentle v. Pine Valley Apartments, 631 So.2d 928, 932 (Ala. 1994).
  • "Pit bulls as a breed are known to be extremely aggressive and have been bred as attack animals." Giaculli v. Bright, 584 So.2d 187, 189 (Fla. App. 1991).
  • "Pit bulls bit[e] to kill without signal." Starkey v. Township of Chester, 628 F. Supp. 196, 197 (E.D. Pa. 1986).
  • "The Pit Bull's massive canine jaws can crush a victim with up to two thousand pounds (2,000) of pressure per square inch - three times that of a German Shepherd or Doberman Pinscher." State v. Peters, 534 So.2d 760, 764 (Fla. App. 1988), review denied, 542 So. 2d 1334 (Fla. 1989).
  • "[P]it bull dogs represent a unique public health hazard . . . [possessing] both the capacity for extraordinarily savage behavior . . . [a] capacity for uniquely vicious attacks . . . coupled with an unpredictable nature" and that "[o]f the 32 known human deaths in the United States due to dog attacks . . . [in the period between July 1983 and April 1989], 23 were caused by attacks by pit bull dogs". Hearn v. City of Overland Park, 244 Kan. 638, 650, 647, 772 P.2d 758, 768, 765, cert. denied 493 U.S. 976, 110 S.Ct. 500, 107 L.Ed.2d 503 (1989).

In Colorado, the city of Denver established a breed ban even though the state legislature opposed it. In a case involving Denver's ban against pit bulls, the city's ordinance was held to supercede a state statute banning all breed specific laws. See Nelson, Kory A., "One City's Experience: Why Pit Bulls Are More Dangerous and Breed-Specific Legislation is Justified," Municipal Lawyer, July/August 2005, Vol. 46, No. 4., pp. 12 et seq., discussing the case, City and County of Denver, et al., v. State of Colorado, No. 04CV3756 (Denver Dist. Ct.).

In City of Toledo v. Tellings, the Supreme Court of Ohio ruled that a Toledo city ordinance that restricts and regulates the ownership of pit bull dogs does not violate the constitutional rights of dog owners. (Download the entire opinion or read the court's detailed press release.) The majority of the court relied heavily upon a number of verified, negative facts about pit bulls that were proved in the trial court. The dissenting judge gave her approval to the ordinance but said that the overwhelming evidence should lead to law enforcement activity against dog owners who make their dogs more violent. The court's majority opinion stated there is "substantial evidence" that:

"[P]it bulls, compared to other breeds, cause a disproportionate amount of danger to people. The chief dog warden of Lucas County testified that: (1) when pit bulls attack, they are more likely to inflict severe damage to their victim than other breeds of dogs; (2) pit bulls have killed more Ohioans than any other breed of dog; (3) Toledo police officers fire their weapons in the line of duty at pit bulls more often than they fire weapons at people and all other breeds of dogs combined; (4) pit bulls are frequently shot during drug raids because pit bulls are encountered more frequently in drug raids than any other dog breed.... The evidence presented in the trial court supports the conclusion that pit bulls pose a serious danger to the safety of citizens. The state and the city have a legitimate interest in protecting citizens from the danger posed by this breed of domestic dogs."

Justice Maureen O'Connor concurred in judgment only, and entered a separate opinion expressing her "disapproval" of the provision of state law classifying all pit bulls as "vicious dogs." She wrote that data cited by the trial court regarding pit bull attacks did not reflect inherent violent characteristics of the breed but rather arose from deliberate efforts by some owners, including drug dealers, to increase a dog's aggression and lethalness through abuse or aberrant training.

"Almost all domestic animals can cause significant injuries to humans, and it is proper to require that all domestic animals be maintained and controlled. Laws to that effect are eminently reasonable for the safety of citizens and of the animal," wrote Justice O'Connor. "Because the danger posed by vicious dogs and pit bulls arises from the owner's failure to safely control the animal, rational legislation should focus on the owner of the dog rather than the specific breed that is owned."

Pit bulls are not the only dogs that come with a legal "handicap." In the Diane Whipple case, the court permitted a great deal of evidence that the Presa Canario dog is inherently dangerousness, and allowed the prosecution to argue to the jury that the defendants had to have known of that evidence and therefore that their possession of dogs of that breed demonstrated evil intentions that warranted convictions of crimes all the way up to second degree murder. Attorney Kenneth Phillips, whose commentaries on the trial were carried by all the major American media, called the Whipple trial a "breed specific prosecution." (See The Diane Whipple Case.) The Whipple case illustrates the modern approach to the legal liability, both criminal and civil, of dog owners based entirely upon the breed of the involved dog.

In State of West Virginia v. Michael and Kim Blatt, the Supreme Court of West Virginia refused to allow a lower court to take judicial notice of the proposition that all pit bulls are inherently vicious:

The inquiry into whether breed-specific presumptions are appropriate or justifiable has been the subject of numerous court cases and scholarly publications. Those opposing such presumptions argue that any dog, regardless of its breed, “can become dangerous under the right set of circumstances[; thus,] banning particular breeds will not achieve the result that communities desire—to reduce the number of dog bites and the injuries sustained from such bites.” Heather K. Pratt, Comment, Canine Profiling: Does Breed-Specific Legislation Take a Bite Out of Canine Crime?, 108 Penn. St. L. Rev. 855, 876 (2004) (footnote omitted). Others question whether “there [is] a rational relationship between public safety and subjecting dogs . . . to unusual restrictions based on their appearance [instead of] their behavior.” Swann, supra note 2, at 851. Those in favor of pit-bull-specific presumptions rely on what are “allegedly immutable pit bull characteristics,” Id. at 852, tied to the breed’s “genetic constitution,” Id. at 835, or the fact that pit bulls were bred as fighting dogs. Id. at 841 (“Thanks to the perverse ingenuity of those who cultivated aggressiveness in the breed, the pit bull now epitomizes a paradox: man’s best friend turned natural enemy of humanity.” (internal quotation marks omitted)). Similar positions have been taken with regard to other breeds, ncluding German Shepherds and Rotweillers. See Mcneely & Lindquist, infra Part III.B.2, at 109.

In view of the disagreement surrounding breed-specific presumptions, it is clear to us that the viciousness or dangerousness of any breed within the meaning of W. Va. Code § 19-20-20 is not a simple factual matter of which a magistrate or circuit court can take judicial notice. See Rivers v. New York City Hous. Auth., 694 N.Y.S.2d 57, 58
(N.Y. App. Div. 1999) (concluding that the court below had erred by taking judicial notice of “the vicious nature of pit bulls”); Carter v. Metro North Assocs., 680 N.Y.S.2d 239, 240 (N.Y. App. Div. 1998) (“On the subject of the propensities of pit bull terriers as a breed there are alternative opinions that preclude judicial notice such as was taken by the Court.”); Tracey v. Solesky, 50 A.3d 1075, 1091 (Md. 2012) (Greene, J., dissenting) (“[W]hy should appellate courts even consider taking judicial notice of facts relating to dog bite statistics that are clearly in dispute?”); cf. syl. pt. 2, Johnston v. Mack Mfg. Co., 65 W. Va. 544, 64 S.E. 841 (1909) (“The habits and propensities of domestic animals are matters of common knowledge to all men, and expert testimony to prove the vicious propensities of a particular kind of animals in general, after they become a certain age, is inadmissible for the purpose of proving that the owner of an animal of that class had knowledge of his vicious propensity.”). Given the conflicting positions with regard to breed-specific presumptions and the public policy underlying such presumptions, it is apparent to us that the Legislature is far better equipped than the judiciary to consider the adoption of a breed-specific presumption . . . . " (Ibid., pp. 25-28.)