While a lot has been written about recognizing relationships between people and their animal companions, few authors have confronted those relationships under the law, and fewer still have addressed the ability to evidence such relationships in a courtroom. Everyone knows that a great many types of animals, especially dogs, have personalities. Under the law, however, evidence rules don't usually allow those personalities to be explained through testimony, especially testimony as to an animal's meaning or intent. While animals, lacking the capacity for speech, themselves could not be witnesses in a trial about such things, many human witnesses certainly seem competent to testify about what they might believe an animal was truly thinking or feeling. So why is such testimony often prohibited?
The law considers animals to be personal property, and – like hats, hammers, and hamburgers – animals have always been subject to rules affecting trade: animals are owned, bought, and sold as products on the open market; used as equipment or tools; and harvested as sources of food and raw materials for production. On the other hand, animals are fundamentally distinct from all other types of personal properties in three ways. One, they can manifest intent. Two, they can independently move themselves from location to location in expressing that intent. Three, they can reproduce. Hats, hammers, and hamburgers cannot do those things. All laws regulating hunting, trapping, animal domestication, and animal husbandry owe their basis to the unique capacity of animals to independently transport themselves over large distances and to compound their value over time. In short, animals are the only personal properties with intentions and with the means to express them. Since that intent is a significant component of the "personality" of the animal, you would think that evidencing that personality on the witness stand is a necessary component of recognizing what animals truly are to people.
Another thing animals are not, of course, are machines, and intentional, as opposed to automatic, behavior is a main key to unlocking a significant legal distinction in type between dogs and dishwashers. Intentionality is manifested by the phenomena of expression, and animals express themselves in numerous ways, including by showing strong preferences and strong dislikes, slight interests and slight disinterests, seemingly uncontrollable assertions and seemingly unalterable hesitancies, piercing attentions and vague distractions, persistent dispositions and temporary desires. Dishwashers do nothing of the sort.
Recognizing those differences does not require our acceptance that we also know what animals must think in general, or that they always have thoughts, or what their particular thoughts might be at all in a certain situation – only that their expression of intent can often be shown. Since Descartes, many have been concerned about whether animals do or do not have "thoughts hidden in their bodies", yet whatever that answer is, it should not constrain evidence that equates particular behaviors with particular intents: "[T]he idea that we cannot determine whether dogs have thoughts in them is a dreadful confusion…The relevant question is whether they express thoughts."
The subject of whether a dog's intent could truly be ascertained has historically been the domain of the philosophizing field biologist, the armchair animal behaviorist, or the itinerant veterinarian. Lawyers, however, are very well acquainted with the practical difficulties of expressing in words the internal experience of another – about their heart, their mind, whatever it is one cannot see but feels – in a systematic way, in a way that relates their experience to everyone else's:
"What we call explaining behavior requires a certain kind of generalization: I tell you what someone did by describing his mind, and we all have minds, so you understand his experience and can compare it with your own experience and the described experience of others. The pressure to keep unfolding the unique is resisted in favor of an explanation that connects, that makes experience common. So it is that we have theories of psychology and morality, images or models that enable us to speak of the normal mind and the abnormal."
Many people are not so certain that animals even have minds, and become uncomfortable, at least in a formal legal setting, suggesting that people share generalized mental experiences with any other group other than themselves. While they are fairly certain that animals such as dogs probably have some manner of internal experience, they are not sure at all what manner it is and whether they personally would be able to identify or relate to the experience in any like manner. Theories of psychology and morality are nearly exclusively theories of human psychology and morality; it is the rare philosopher that has attempted to assess animal psychology or animal morality as a subset of the human realm. It is probably for that reason that judges and legislators consistently resist applying to animals the evidentiary rules that allow (and prohibit) witnesses from speaking of other's internal experiences.
To that end, courts historically have forbidden witnesses from assessing animal intentionality. As one judge put it, any attempt to determine a dog's present intent would apparently mire juries in a "morass of subjectivity." Instead, an animal's intent is simply presumed to flow from the animal's past conduct. Evidence rules usually provide that an animal's intent be determined solely from its "propensity" for engaging in certain types of behaviors.
As to dogs specifically, the presumption has been that dogs have a natural propensity for just being good. Judicial determinations of dog intent, for instance, often do not extend any further than the fairly pedestrian assumption that dogs are, in general, harmless animals. People, to the contrary, are not assumed in the law to be "naturally good" creatures, and do not appear to have a judicially determined propensity for anything nearly as straightforward as digging or running. Human intent is whatever the actor in question says it is, and the validity of the statement may be and often is challenged by showing the actor's nonconforming conduct. Evidence of other acts, while admissible to show things like motive or opportunity, is not admissible to prove the character of a person in order to show that he or she acted in conformity. "Propensity" evidence of a person's history of bad acts is normally excluded due to the danger of unfair prejudice, of confusion of issues, and of misleading the jury. Nevertheless, it is hard to describe what is so different between people and animals (in the way they non-verbally express their respective traits) that it requires rejecting propensity evidence for the one and demanding it for the other. In a sense, as to character traits and character overall, "propensity," while the rule for dogs, is the exact opposite of the rule for people – yet there is little sense to why this is so other than that one group can talk and the other can't.
The lack of a spoken language does not have to be an insurmountable obstacle in the law Some courts recently have allowed factual disputes as to the "playfulness" and "maliciousness" of dogs to go to the jury. Such cases suggest that animal intentionality based on the informed interpretation of behaviors, at least for dogs, might slowly be on the verge of becoming a proper topic for witnesses. Mostly, however, the law on whether and how an animal's personality may be presented to a jury remains a confused muddle. In most cases, testimony is simply about an animal's particular behaviors, rather than about what those behaviors might signify as to larger aspects of its personality. In criminal nuisance actions brought by municipalities against dangerous animals, courts have allowed consideration of some basic traits of an animal, but are loathe to consider others. Many courts have indicated that the "habits, characteristics, and instincts" of domestic animals may be judicially determined. How a particular animal may have manifested its character is more and more a pertinent question in adjudicating municipal ordinance violations regarding animal control; recently, an expert witness was allowed to testify about a dog's "dominant personality" and stated that when the owner fails to show dominance, the dog will view the owner as subservient.
In addition, in at least one civil case, a witness was allowed to describe the personality of a dog at the time it was sold in circumstances where the seller was claimed to warranty changes in a dog's future personality. In doing so, the court noted that such a warranty would be inappropriate given that "animals are exposed to an ever-changing environment and may also change, themselves, accordingly." At least that judge recognized individual personalities as dynamic. Still, these cases are the exceptions, not the rule. Normally, testimony about a dog's personality is simply excluded, and even witnesses who wish to testify simply as to particular physical qualities of an animal must pass a threshold showing that they are someone sufficiently acquainted with the animal to so testify.
Worse, and as to dogs specifically, some courts have held "breed personalities" to subsume any individual personality of a dog, the capacity of an animal to express individuality notwithstanding. In those cases, what a dog actually intended, therefore, or is actually like in character, is given a back seat to what a judge feels its breed relegates it to have to be like. The idea of breed profiling has gained some legitimacy even though it reduces dog status back to that of uncontrollable automatons. One would think that the common law presumption about dog behavior -- that all dogs are presumptively good dogs – is reasonable, and should be unassailable. Nevertheless, certain courts have sought to reverse the rule and accept instead the "innate viciousness" of certain breeds.
Can any breed be legally determined to be "innately vicious," or is the focus on those with culturally tarnished reputations? While the idea of breed profiling appears to be a step backward from progressing the concept that animal personalities should be relevant, the practice of breed profiling nevertheless accomplishes the same goal: the only difference is that it will simply be owners rather than victims who will be compelled to utilize such testimony to contest animal ethology experts and evolutionary biologists enlisted to prove that animals cannot overcome certain innate qualities.
For example, in a case in which expert testimony from an experienced dog trainer concerning the characteristics and propensities of boxer dogs was allowed, an expert testified that boxers are a protective type of dog and have a propensity for jumping, yet admitted that he was not familiar with the specific dog at issue and that dogs have different personalities within their own breed. In allowing that testimony, the court admitted that while jurors have some knowledge about the characteristics of dogs in general, they might not be familiar with the propensities of a particular breed. More and more detail as to what an animal's conduct "means" (both to itself and to people) seem to be required.
A large part of the problem is semantics, and a set of definitions could be established. The terms courts employ frequently overlap as well as fail to intersect at crucial junctures. In another case, an experienced veterinarian held an "evaluation session" with a Rottweiller and its mixed breed daughter, and testified on the stand simply that "[t]he pair had a predatory aggression…toward other animals, but did not have an aggression or vicious disposition toward humans." The judge nevertheless accepted and relied upon other observations that the two dogs in the case were, respectively, "dominant" and "a follower," that one dog was "sweet and docile," and that one was "tougher" whereas the other was "readier to back off." The terms used were a smorgasbord of human psychological and regionally colloquial phrases neither internally consistent with each other, nor externally consistent with the expert's own limited determination. Though it is not uncommon for a court to rephrase an expert's technical characterizations, the laxity with which intentionality terms are applied to animals, when compared to the rigor with which they are applied to people, is striking – and unsupportable.
Personalities are composed of traits, there being two primary types:
A. Traits expressed through physical acts (what the law calls "behaviors")
1. Genetically programmed behaviors (what the law calls "instinctual acts")
2. Learned behaviors (what the law calls "intentional acts")
a. Spontaneous or unique learned behaviors
b. Certain patterned learned behaviors (what the law calls "habits")
B. Traits expressed through symbolic acts (what the law calls "demeanor")
1. Genetically programmed demeanor (what the law calls "propensities")
2. Learned demeanor (what the law call "character")
In sum, personalities manifest themselves through an individual's physical and symbolic acts, acts that in turn may be either innate or learned. Reconsider words such as "playful" and "vicious", words prevalent in cases on animals which really are only descriptors, free-floating adjectives that may be applied in different ways. One can engage in a vicious act, that is behave viciously, or, alternatively, one can have a vicious demeanor, that is, appear vicious in attitude without specifically doing anything vicious. In either case, the reason for doing so may be that the person is programmed to have done so (he is "innately vicious") or that the person has learned to do so from others or his environment (he is "intentionally vicious"), yet in both cases, viciousness is still considered part of his personality. In the former scenario – being innately vicious – the conduct is outside the person's control, whereas in the latter scenario – being intentionally vicious – the conduct is under some manner of control. True, the control may be impaired by a universe of circumstances, from the ingestion of substances to an unhappy upbringing to the evil influence of others, but at least control may be presumed to exist at the inception.
Judicial notice of the habits and instincts of domestic animals is based on outmoded and simplistic perceptions about the real and complicated nature of the interactions that occur between people and animals in modern society. People as a group simply do not often have a good handle at all on what many animals' "habits," "instincts," or "impulses" are truly like, even though the law presumes that they should. The select faction of people that do have a good handle on an animal's "habits," "instincts," or "impulses" are invariably the animal's owners. It is they who are most familiar with an animal's past, present, and likely future; it is they who are most aware of what it took to obtain the animal, what it took to control the animal, what it took to tamp down the animal's instincts and propensities, and what it took to raise up the animal's habits and character.
Because owners are socially bound to understand and account for their animal's personality, they must be allowed as well to evidence what they know personally about the animal's mind as well as about its body. It would not be that hard to adjust rules already in place that protect the relevance and materiality of facts elicited from the witness stand, even though the issue is of an animal's character, behavior, or value as opposed to a person's. People and animals have personalities, composed of all the myriad and sundry traits to which any personality is potentially subject, albeit learned or genetic. Yes, under that definition, the "personality" of an earthworm does exist, although it may be expressed as the sum of one single trait, the relatively boring, genetically-programmed instinctual behavior of digging. And yes, the personality of an Irish Setter as well exists, and in turn may be both more complex than the earthworm while somewhat less complex than the human who owns him. A setter's act of digging, sitting on a spectrum of many traits acting in concert, is merely a smaller piece to a much larger puzzle than that presented by an earthworm, and reflective of a host of relatively interesting forces stemming from both nature and nurture. Biology and ownership jointly contribute to animal personalities.
 Malcolm, N. Thoughtless Brutes. Proceedings and Addresses of American Philosophical Association, 46:5-20,
quoted in Griffen, D. The Question of Animal Awareness: Evolutionary Continuity of Mental Experience.
Rockefeller University Press, New York (1976).
 White, J.B. The Legal Imagination University of Chicago Press, Chicago (1973) at p. 181.
 Lewellin v. Huber, 456 NW 2d 94 (Minn. App. 1994); Eritano v. Com., 690 A.2d 705 (Pa. 1997).
 Johnson v. Lindley, 41 F. Supp. 2d 1021 (D. Neb. 1999).
 See, e.g., Cullinane v. Board of Selectmen of Maynard 50 Mass. App. Ct. 851, 855 (Mass. 2001).
 Hill v. President and Trustees of Tualatin Academy and Pacific University 61 Or. 190 (1912); Mitchell v.
Newsom 360 SW 2d 247 (Mo. App. 1962); Lloyd v. Alton R. Co. 159 SW2d 267 (Mo. 1941). ); Jarvis v. Koss
427 A2d 364 (Vt. 1981).
 Rothenbusch-Rhodes v. Mason, 2003 WL 22056565 (Ohio App. 10th Dist. 2003).
 Blaha v. Stuard 640 NW 2d 85 (South Dakota 2002). See also, Whitmer v. Schneble 29 Ill. App. 3d 659 (Ill.
1975)(finding no warranty by a seller that a dog's personality would not change in the future).
 Gaffney v. Kennedy, 2003 WL 22149640 (N.Y. Slip Op. 51267(U) 9/2/03); Cayetano v. New York City Housing
Authority, 2003 WL 21355410 (N.Y. Slip Op. 50981(U) 6/4/03).
 Chance v. Ringling Brothers Barnum & Bailey Combined Shows Inc., 478 P.2d 613 (Or. 1970).
 For a particularly egregious example, see Arnold v. Lair 621 P.2d 138 (Wash. 1980) (using "tendencies,"
"disposition," "demeanor," "condition," and "propensities" interchangeably).
 Cullinane v. Board of Selectmen of Maynard 50 Mass. App. Ct. 851, 855 (Mass. 2001).
Personality: complex of personal and social traits that distinguish one individual from another
Trait: one of the several distinguishing qualities that make up a personality
Behavior: to conduct oneself in a particular way
Instincts: inheritable and unalterable tendency to specifically respond to stimuli without involving reason
Habits: pattern of intentional behavior acquired by frequent repetition
Demeanor: conduct or bearing expressed symbolically, aka attitude
Propensity: inheritable and unalterable inclination for a certain type of behavior toward others, aka disposition
Character: complex of mental and ethical traits marking a person formed from the influence of one's environment
 Lorenz, K. Man Meets Dog. Kodansha International, New York (1953) at pg. 21: "Everybody who has owned
more than one dog knows how widely individual canine personalities differ from each other."