certain dog breeds more dangerous than others?
Whether or not certain dog breeds are more dangerous than others has
been the subject of considerable discussion among ethologists and
veterinarians, especially with regard to the usefulness of
breed-specific legislation as an attempt to protect a community’s
citizens from dog attacks/bites. Breed-specific legislation is
based on the assumption that there are genetic differences among
breeds with regard to their dangerousness/aggressiveness.
However, many veterinarians and ethologists oppose breed-specific
legislation, arguing that the genetic make-up of an individual
animal is only one of many components that may enhance its
Factors that may influence the specific danger of a dog bite/attack
imposed by an individual dog include (1) the temperament and (b) the
body characteristics of a dog, (3) the individual personality of the
dog owner, (4) the specific circumstances of a bite incident, and
(5) the individual personality of the victim4.
Breed-specific legislation is based on the assumption that the first
two criteria, characteristics of the animal itself, are the most
important factors that influence the potential danger imposed by
dogs. If this was true, comprehensible differences in
temperament and/or body characteristics among dog breeds would be
expected. For example, we would expect that all pit bull-type
dogs differ significantly in their temperament from other breeds.
Just operationalizing the notion of temperament is complex.
The temperament of a dog is defined as the sum of all his inherited
and acquired physical and psychological traits, characteristics and
abilities, which determine, shape and regulate the dog’s responses
to his environment3. Experiments investigating
temperament differences among breeds must be based on objective
temperament evaluation, which proves extremely difficult, since the
environment is a variable difficult to control and standardize.
This is also true for the investigation of specific temperament
traits such as aggression4.
Aggressive behavior in dogs is a species-specific trait which is
genetically firmly established, because it has been highly
influenced by natural selection during evolution as well as by
artificial selection through man (e.g., selecting for inter-specific
aggression in most guarding breeds and so-called fighting dogs)2.
However, the fact that the aggression level of members of certain
breeds can be increased (or decreased) through artificial selection
does not prove that aggression itself is a highly hereditary trait4.
In most cases, dogs that have been selected for high levels of
aggression are raised in a very aggression-stimulating environment.
Unfortunately, the blame for aggressive behavior in these dogs is
usually solely placed on their genetic make-up, while environmental
factors are often ignored. Environmental and learning effects
however, are always superimposed upon genetic influences1.
Thus, early isolation and neglect as pups (e.g., in so-called “puppy
mills”), training to attack other dogs and humans, and a
low-stimulus environment with inappropriate exercise are factors
that “create” dogs with social deficits (i.e., lack of appropriate
interdog communication) which have an unstable position in their
group (unstable dog-owner relationship), and are hard to influence.
Aggression in these dogs is rather a symptom of a behavioral
disorder than a regulative species-specific behavior1.
The “dangerousness” of a particular breed is also often blamed on
certain physical characteristics, which are generally easier to
evaluate than temperament, since most of them can be measured.
They include parameters such as body weight and height, power, jaw
strength, pain threshold, as well as age and sex of the dog.
Body weight, height and length are measurable parameters which vary
immensely among breeds. Power and speed also differ among
breeds. However, the power of a dog is not only based on his
genetic make-up, but also depends on his training condition.
Jaw strength is another measurable parameter. Although certain
dog breeds such as rottweiler or American Pitbull Terrier have the
reputation of stronger jaws than others, valuable scientific studies
showing significant differences in jaw strength among breeds do not
currently exist4. It is obvious that a larger and
more powerful dog can potentially do more harm than a smaller,
weaker dog. Even a friendly greeting behavior such as jumping
up on a person can become a potentially dangerous situation,
depending on the size of the dog. It is a fallacy to assume
that all members of large breeds are generally more dangerous than
all members of small breeds. It is not the breed of an
individual dog that makes a situation dangerous, but rather the
The sex of the dog is another body characteristic that plays an
important factor in aggressive behavior. It has been shown
that a majority of dog bites is inflicted by intact young males5.
Thus, intact male dogs are, independently from their breed,
potentially more dangerous than female dogs. Other physical
characteristic influencing a dogs the tendency toward aggression
include a dog’s pain threshold, as well as the animal’s age and
overall health2. No valuable scientific method is
currently available to objectively evaluate differences in pain
tolerance among dog breeds4. Health conditions that
may elicit aggressive behavior can occur in all breeds and do not
justify indiscrimination of certain dog breeds.
In summary, “the classification of dog breeds with respect to their
relative danger to humans makes no sense, as both, the complex
antecedent conditions in which aggressive behavior occurs, and its
ramifying consequences in the individual dog’s ecological and social
environment are not considered”1.
Dr. Cornelia Wagner, DVM, MS
October 18, 2001
D. U. (2001): Zur Biologie der
Aggression des Hundes. Dtsch. Tierärztl. Wschr. 108 (3),
R. (1995): The ethology and epidemiology of canine aggression.
In: Serpell, J. (ed.) The domestic
dog: its evolution,
behaviour and interactions with people. Cambridge University
Press, Cambridge, UK.
E. (1972): Wesensgrundlagen und
Wesensprüfung des Hundes. Cited in: Feddersen-Petersen, D. U. (1992)
Hunde und ihre Menschen. Frankh-Kosmos, Stuttgart, Germany.
(2000): Zur Frage der besonderen
Gefährlichkeit von Hunden auf Grund der Zugehöhrigkeit zu bestimmten
J. C. (1985): Severe attacks by dogs: characteristics of the
dogs, the victims and the attack settings. Public-Health-Reports