Date: September 17, 2024
Author: Roberto Barata
How to cite: Barata, R. (2024). The So-Called “Predatory Aggression”- A Brief Critical Analysis. Human-Animal Science.
Introduction
The term “predatory aggression” is widely used in dog training and some laboratory studies within neuroscience, but it is fundamentally wrong. This term has been linked to the euthanasia of dogs “diagnosed with this condition” in the Netherlands, a practice that raises serious ethical concerns and warrants urgent discussion. This is an example of how inaccurate or misleading terminology, hijacked from other fields and not correctly defined, kills dogs without any consequence.
In veterinary medicine, behaviors are classified as symptoms, while ethologists assess them by function. This distinction is important when dog lives are involved. Such incorrect misclassifications perpetuate fear and stigma around certain breeds, misinforming public perception and legislation. This also raises the suspicion that the term “predatory behavior” is used by those advocating breed-specific legislation (BSL) in the Netherlands.
I’ll keep this brief and focus on the key points from my research, which I’ve been working on for several months. If you’re interested in learning more, I’ve included some references and suggested readings you can follow up on.
Definitions
“Aggressive behavior is behavior directed toward the elimination of competition from an opponent, by injuring it, inflicting it pain, or giving it a reliable warning of such impending consequences if it takes no evasive action. It is distinguishable from dominant behavior in as much as the latter does not include harmful behaviors though it may require some degree of forceful measures. Aggressive behavior ranges from reliable warnings of impending damaging behavior such as growling, roaring, and stamping, to injurious behaviors such as biting, staging, and kicking. Predatory behavior is not aggressive behavior.” (Abrantes, 2014)
Predatory behavior is “the behaviour by means of which an animal of one species, the predator, kills and eats a member of another species, the prey.” (McFarland, 2006).
Other definitions
My research, which spanned a range of sources, including dog training websites, law firms, and insurance companies, revealed varying definitions and explanations of the term.
“Predatory aggression occurs when a dog “hunts” something. Typically, this involves them chasing after a cat or another smaller animal. This type of aggression is not driven by hormones and is instead largely genetic.” https://www.dogster.com/dog-training/how-to-stop-dog-predatory-aggression
“Predatory aggression is usually limited to hunting dogs or dogs with the tendency to chase prey. If directed towards humans, it’s considered the result of a medical or mental condition for your veterinarian to address. Predatory aggression is the rarest of all forms of dog aggression.” https://www.ctvsh.com/services/dogs/blog/7-types-dog-aggression-and-how-nip-them-bud
“Predatory aggression: Motivated by an animal’s drive to hunt and consume food. Often, predatory behavior is seen in dogs chasing smaller dogs, cats or even young children.” https://www.animalhumanesociety.org/resource/aggression-dogs
“While that definition might sound a little murky, I offer it up by way of contrasting it with another aggressive behavior we tend to call “predatory aggression.” In these cases, dogs (and cats) tend to attack animals significantly smaller than themselves. In cases where predatory aggression (and not inter-dog aggression) is assumed, it’s because the attack appears outside the normal context of dog-on-dog violence. In other words, the attacker appears not to have considered his victim a member of his own species. Predatory aggression is normal in many cases. Indeed, when cats do it to birds and small rodents, for example, we call it “natural.” Yet when dogs do it to cats or small dogs, we use words like “vicious,” “dangerous,” or — more behaviorally accurate and biologically apropos — “predatory.”” https://www.embracepetinsurance.com/waterbowl/article/predatory-aggression
“Predatory aggression is an instinctual desire some dogs feel to pursue prey. It is more common in some hunting and tracking breeds – such as hounds and terriers – than others, but any dog can feel the compulsion to chase smaller animals.” https://www.k9ofmine.com/predatory-aggression-prey-drive-in-dogs/
“Predatory aggression in dogs refers to their natural instinctual behavior to chase, capture, and potentially harm prey animals.” https://petcreeks.com/predatory-aggression-in-dogs/
“Predatory Aggression: Some pet dogs show classic canine predatory behaviors, including chasing and grabbing fast-moving things.” https://www.aspca.org/pet-care/dog-care/common-dog-behavior-issues/aggression
“One of the key factors that distinguish predatory aggression from other forms of aggression is that movement often triggers it. In the wild, this movement is in the form of running and escape attempts of a small critter that the dog has honed in on as his prey. In the domestic situation, joggers, skateboarders, cyclists, automobiles, people on bicycles and running children frequently awaken the dog’s otherwise dormant predatory instincts.” https://acmecanine.com/predatory-aggression-in-dogs/
“Predatory aggression is usually recognized by the behavior sequence: visual or auditory stimulation triggering a generally silent and direct approach or chase, capture, and kill the prey. The prey is rarely eaten. If a group of dogs exhibit predatory aggression, the chase may not be silent. Many dogs will chase small prey or animals without capturing or killing them. There is therefore a distinction between chasing (part of the predatory behavior sequence) and predatory aggression (chasing, capturing, and killing prey).” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3659447/
VCA Animal Hospitals: “Predatory Aggression. Aggression directed toward typically another animal, yet occasionally a person, which is motivated by the desire to hunt, capture, kill, and consume species viewed as prey. Predatory aggression is typically silent or absent of vocalizations and the bite is often damaging or uninhibited.” https://vcahospitals.com/know-your-pet/fear-vs-aggression#:~:text=Predatory%20Aggression.,is%20often%20damaging%20or%20uninhibited.
“A canine may act aggressively towards anything it perceives as prey, most often smaller animals. This instinct has to do with the quick movement of the prey, so smaller animals—or even a person on a bicycle—can trigger predatory aggression.” https://dominguezfirm.com/injury-lawyer/dog-bites/what-causes-canine-aggression/
Wood (1998): “Predatory aggression involves such activities as stalking other animals for a kill, the violence that ensues when one animal infringes upon the marked territory of another, or the posturing and attacks exhibited by nursing mothers when any animal, even the mate, approaches the nest.” https://www.sciencedirect.com/science/article/abs/pii/B0080427073001668
The American Psychological Association defines it as “aggression directed toward the capture of prey. Predatory aggression is more properly considered a form of foraging than aggression per se. https://dictionary.apa.org/predatory-aggression
The US Legal says that “Predatory aggression refers to motivated attack behavior. It is directed to natural prey and the aggression is deeply routed in early hunting behavior. (…)Predatory aggression is an attack mode of violence.” https://definitions.uslegal.com/p/predatory-aggression/
There is also the term “Predatory drift,” coined by Ian Dunbar, which refers to situations when one dog “thinks” another dog is prey because of their wolf ancestry. In this situation, dogs are not being aggressive but rather doing what “comes naturally” because it’s what their ancestors did in these situations. I could not find academic references for this definition.
Discussion one
From all of them, Siegel’s definition was what caught my attention in his 2005 book “The Neurobiology of Aggression and Rage”, where all the “predatory attack” is based on former studies on cats, perhaps like this one (https://psycnet.apa.org/record/1965-06941-001).
Let’s analyze it: “Predatory aggression. This form of aggression is basically unrelated to the other forms of aggression described above and can be distinguished from them because (1) it is specifically triggered by the presence of a prey object within the visual field of the predator, and (2) a predator will display predation regardless of the environment in which it is placed. (…) However, it should be noted that because it is different from other forms of aggression, predatory attack may be viewed by some ethologists not as a form of aggression, but rather as behavioral strategy in association with feeding behavior.”
First, It is important to note that the term “predatory aggression” is not well defined, and most of it came from lab experiments using electric and chemical elements. In the dog world, I suspect that was Beaver’s 1999 Canine Behavior: A Guide for Veterinarians book that introduced this term, based on a study where p-chlorophenylalanine was injected in rats (https://psycnet.apa.org/record/1973-28324-001). It raises the suspicion that the veterinary field brings concepts from other fields and applies them as “symptoms.” Lindsay’s Handbook of Animal Training and Behavior Series also mentions the term, referencing it to Siegel & Edinger (1981), classifying it as a “quiet attack” and linking it to the Lateral Hypothalamus, which I’ll discuss further. Again, those studies had no precise definitions, especially in the first ones from the 1960s and the other mainly from the 70s. Perhaps the main reason for this ripple effect of using this term without an accurate analysis and using them as the main premise for other works, especially in the neuroscience field, which can inadvertently jeopardize all the research made since then and make it a challenge for a deep critical analysis in this term because it has become somewhat entrenched in the vocabulary of neuroscience and behavioral studies making it familiar even if technically wrong, like these, for instance, mixing terms from veterinary, psychology, neuroscience, and ethology (https://onlinelibrary.wiley.com/doi/abs/10.1002/bsl.842 , https://www.sciencedirect.com/science/article/abs/pii/S0166432815000479, https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1460-9568.2010.07429.x).
Below are a few links from my research to papers mentioning the term without a clear definition. Quite the opposite, chasing and biting seem to be the main factors for this classification, which I’ll discuss further.
https://www.ojp.gov/ncjrs/virtual-library/abstracts/kinds-aggression-and-their-physiological-basis
https://psycnet.apa.org/record/1974-06634-001
https://www.sciencedirect.com/science/article/abs/pii/0006899373905234
https://link.springer.com/chapter/10.1007/978-1-4684-3066-0_8
https://brill.com/view/journals/beh/69/3-4/article-p183_4.xml
https://www.sciencedirect.com/science/article/abs/pii/S0163104780927685
Second, the fact that the presence of a prey object triggers predatory behavior suggests that it is a response to a specific stimulus rather than a general state of aggression. This contrasts with other forms of aggression, often triggered by a perceived threat, competition, or territorial defense. The specificity of the stimulus and the predator’s response to it confirms that predation is a distinct behavioral category not driven by aggression.
Third, the fact that a predator will display predation regardless of the environment in which it is placed suggests that predation is a highly motivated and goal-directed behavior. The fact that predation can occur in various environments without being influenced by the specific context confirms that it is a behavior driven by a specific motivation (e.g., hunger) rather than a general state of aggression.
Finally, his mention of the ethology disagreement on this term confirms my previous statements and is a red flag when you read these terms in other fields, like veterinary and neuroscience.
Discussion two
In the book Brain & Behavior, Garret and Hough confirm my points on Siegel’s comment: “Predatory aggression occurs when an animal attacks and kills its prey or when a human makes a premeditated, unprovoked attack on another. Predatory aggression is cold and emotionless, whereas affective aggression is characterized by its impulsiveness and emotional arousal. Although these terms have been useful in animal research, the terms instrumental and impulsive seem more descriptive of aggression seen in humans. Instrumental aggression is unprovoked and emotionless, and is intended to bring about some gain for the aggressor, for example, to intimidate or rob the victim. Impulsive aggression occurs in response to a threat, real or imagined, and is characterized by heightened emotionality. These two types of aggression are sometimes referred to as proactive and reactive, for obvious reasons.”
This brings up five important points:
1- The term ‘predatory aggression’, according to the authors above, is often used in these fields to describe a “type of aggressive behavior” that occurs when an animal attack and kills its prey or when a human makes a premeditated, unprovoked attack on another and is characterized by being cold and emotionless, similar to instrumental aggression, which is unprovoked and aimed at achieving a specific gain, such as intimidation or robbery.
2- There seems to be confusion between “attack” and “aggression,” not only in these fields but also from the websites above. An attack is an “assault upon prey or rival, using weapons designed to kill or maim. In the context of predatory behaviour, attacks are usually the culmination of a period of ambush or hunting” (McFarland, 2006). I would add that there is also a misunderstanding regarding the term “threat.” A threat “is a stimulus that most often precedes a behavior that may harm, inflict pain or injury, or decrease an individual’s chance of survival. A social-threat is a threat (a threatening behavior) from another individual or group of individuals that may cause submissive behavior or flight resulting in the temporary loss of a resource, but not injury.” (Abrantes, 2011).
3- Although ‘predatory aggression’ is a term used in these fields for the reasons above, it is more accurate to categorize this behavior as proactive instrumental aggression rather than a separate form of aggression incompatible with its function (predation + aggression). Several scholars explicitly define “predatory aggression” as a proactive, instrumental form of aggressive behavior, which, by their own definition, is distinct from predation. This raises an interesting question as to why the term “predatory” continues to be used in this context, given its incompatibility with the concept and function of predatory behavior: https://www.sciencedirect.com/topics/psychology/predatory-aggression
4- Aggressive behavior can be categorized into two types: reactive and instrumental aggression. Reactive aggression is driven by a desire to create distance or terminate a confrontation and is often accompanied by intense emotional displays. Instrumental aggression, on the other hand, is goal-oriented and may appear more calculated with less overt emotional expression. (Nelson, 2006). Note that this author also uses the term “predatory aggression” on the same terms as all the other authors.
5- I consider it necessary to mention the other two terms used, which are sometimes used interchangeably and mixed with proactive (instrumental) aggressive behavior and reactive impulsive aggressive behavior: Affective and Appetitive aggression. Affective aggression refers to aggressive behavior driven by emotions. This type of aggression is often impulsive and typically responds to a perceived threat or provocation. Affective aggression is similar to reactive-impulsive aggression. On the other hand, appetitive aggression refers to aggressive behavior driven by a motivation to achieve a goal. This type of aggression is often premeditated, goal-oriented, and is typically characterized by a sense of pleasure or satisfaction derived from the aggressive act. Appetitive aggression is similar to proactive aggression.
Other considerations
Both the general public and some academic sources frequently overlook that not all attacks are driven by competitive motives. This oversight contributes to the common misconception of “predatory aggression.” The function of predatory behavior, primarily driven by the need to acquire food or ensure self-preservation, is fundamentally distinct from the function of aggressive behavior, which is typically aimed at eliminating competition.
Neuroscientifically, “predatory aggression” is often linked to the lateral hypothalamus (LH), a brain region that regulates feeding behavior. However, this association is based on misunderstanding the LH’s function. The LH is not a “center” for aggression but rather a region that integrates sensory information related to food and hunger. Stimulation of the LH can elicit feeding behavior, but it does not necessarily lead to aggressive behavior. (https://www.degruyter.com/document/doi/10.1515/nf-2016-A049/html)
The neural mechanisms underlying predatory behavior and aggression are distinct. Predatory behavior is primarily driven by the ventral tegmental area (VTA) and the nucleus accumbens (NAcc), part of the brain’s reward system. These regions are involved in processing sensory information about prey and the motivation to pursue it. The function of predation is to obtain food, characterized by focused and goal-directed behavior. In contrast, aggression is primarily regulated by the amygdala and the prefrontal cortex, which are involved in processing emotional and social information.
The brain regions involved in predation and aggression are distinct. The predatory sequence, which includes stalking, chasing, and killing, is mediated by the brain’s predatory circuitry, which involves the VTA, the substantia nigra, and the amygdala. In contrast, aggression is mediated by the brain’s defense circuitry, which involves the hypothalamus, the amygdala, and the periaqueductal gray.
The movement pattern of chasing, often associated with “predatory aggression,” is also distinct from aggressive behavior. Chasing is a specific locomotor behavior involving rapid and directed movement toward a target. In predation, chasing is often accompanied by a “pursuit curve,” a characteristic movement pattern involving rapid acceleration and deceleration as the predator approaches its prey. In aggressive behavior, the act of chasing is not merely a display of speed but a calculated approach aimed at achieving a specific goal—namely, the successful interception of the target. However, we should also consider that dog-chasing behavior can be driven by curiosity, play, allelomimetic behavior, and many other possible and complex contexts.
The same applies to some breeds’ “high prey drive” discussion. This drive can increase their likelihood of catching and killing prey, but it is not inherently related to aggressive behavior. As I wrote above, the drive to chase and pursue is an instinct separate from aggressive behavior.
When a large dog attacks a small dog or a human, calling it “predatory aggression,” the behavior’s function is wrongly analyzed. This is especially true considering domestic dogs have complex social behaviors involving aggression for reasons other than predation. More often, such incidents would be categorized based on aggression principles rather than predation unless there is clear evidence that the behavior was motivated by an attempt to hunt for food, which is relatively rare in well-fed domestic dogs.
Dogs can differentiate between other dogs and other species and have a complex understanding of social hierarchies and relationships. They can recognize and respond to species-specific signals, such as body language and vocalizations. Dogs have a unique brain structure dedicated to processing social information (Berns et al., 2012), and they can form complex social relationships with other dogs and humans. Dogs use body language and vocalization signals to understand the behavior and intentions of others. This process is known as “social referencing” (Miklosi, 2007).
The predatory sequence is a chain of behaviors evolutionarily adapted to capture and kill prey, and selective breeding has enhanced individual links in this chain for other purposes. The discussion point is that the function and brain circuits influencing these behaviors might have changed, even if they appear similar. For example, when a pointer stalks, it’s not driven by the same predatory sequence as a wild canid stalking prey. Instead, it can be driven by a learned behavior shaped by selective breeding and training.
To a certain degree, we can say that the individual links in the chain have taken on new functions, even if they originated from the predatory sequence. So, even if we assumed that the behaviors of pointers, cattle dogs, and greyhounds originated from the predatory sequence, they no longer operate as part of that sequence in the classical sense. I would argue that these behaviors have become maladaptive because they no longer serve their original function. As a result, they may reduce the species’ overall fitness by diverting energy and resources away from more adaptive behaviors, potentially leading to a loss of genetic variation and decreased ability to adapt to changing environments. Additionally, it is unclear how an individual would distinguish between a threat and potential prey. This could lead to confusion and maladaptive responses, bringing more questions about how it would work with smaller breeds. It also might result from the consequences of human selective breeding and domestication, which can disrupt a species’ natural behavioral repertoire and erode its evolutionary potential, and is another longer and necessary future discussion.
Some breeds, such as greyhounds and cattle dogs, have been selectively bred to accentuate their prey drive, challenging the distinction between predatory behavior and social behavior. However, even in these breeds, it’s possible to identify the characteristics of predatory behavior and differentiate it from social behavior. For example, if a Greyhound chases a Poodle, it can be an example of social or agonistic behavior related to conflict or competition. If a Cattle Dog attacks a skateboard, its behavior can be driven by its strong herding and chasing instincts, triggered by the skateboard’s movement and speed, not predatory behavior.
Other examples include terriers who still catch rats. Their behavior is still part of the predatory sequence, as they’re using their instincts to capture and kill prey. As for pit bulls that grab, shake, and kill other dogs, it is correct to assume that they’re showing instrumental aggression. In this case, the behavior is not driven by the predatory sequence but rather by the function of the aggressive behavior, following Abrantes’s definition.
Another possible source of confusion is the size of the ‘prey’, as a smaller dog may be targeted not necessarily due to its size but rather as a result of an optimal strategy, where the attacking dog may be more likely to succeed or achieve its desired outcome by targeting a smaller opponent rather than a larger one.
I also explored the hypothesis of conspecific predation, but the existing literature primarily focuses on cannibalistic species. I could not locate a specific study that applies this concept to non-cannibalistic species, such as dogs. Consequently, I will continue to consider the possibility that chasing is, among others, a component of conspecific or intra-species aggression.
Conclusion
The distinction between predation and aggression lies in the motivation and context of the behavior.
The function of the behavior determines its classification: if the goal is to capture or kill for sustenance, it is predation; if driven by play, excitement, or other motivations, it is not. Regardless of the hypothetical scenarios or illustrative examples, they are subjective and do not supersede the underlying functional context because the context and function of the behavior ultimately will determine its interpretation. Therefore, we must also bring Tinbergen’s four questions to the discussion. Whether a behavior is social, predatory, or exploratory depends on the specific circumstances and the dog’s characteristics. Therefore, interpreting a dog’s behavior always brings a degree of subjectivity to the process, and different observers may have different interpretations of the same behavior. Classifying a behavior only by the owner’s report is a wrong process, and it condemns dogs to death.
In conclusion, I find it extremely important that we start to examine and critically define this term across different fields. I refuse to be an accomplice of the current situation in the Netherlands and, indeed, in other countries with other terms. I urge you to step up on the messy scenario of terms and definitions. Nobody seems to really understand some behaviors or critically evaluate the existing ones. I also see that ethology is not being given the deserved recognition and consideration, perhaps because vague terms from other disciplines sound more appealing, like the tendency of the “one-theory = only-truth” in the dog world, which we cannot even question, and that is one of several structural problems that I can now clearly say that is killing dogs.
References and Suggesting Reading
Abrantes, R. (2011). Dominance—Making Sense of the Nonsense. Roger Abrantes. Retrieved September 17, 2024, https://rogerabrantes.wordpress.com/2011/12/11/dominance-making-sense-of-the-nonsense/
Abrantes, R. (2014). Aggressive Behavior- The Making of a Definition. Ethology Institute. Retrieved September 17, 2024, https://ethology.eu/aggressive-behavior-the-making-of-a-definition/
Abrantes, R. (2015). Agonistic Behavior Course. Ethology Institute.
Bandura, A. (1973). Aggression: A social learning analysis. Prentice-Hall.
Beauchamp, G. (2014). Social predation: How group living benefits predators and prey.
Berns, G. S., Brooks, A. M., & Spivak, M. (2012). Functional MRI in awake unrestrained dogs. PloS one, 7(5), e38027. https://doi.org/10.1371/journal.pone.0038027
Breedlove, S. M., & Watson, N. V. (2020). Behavioral neuroscience, Ninth edition. Oxford University Press.
Curio, E. (1976). The ethology of predation. Springer-Verlag.
Kappeler, P. M. (2010). Animal behaviour: Evolution and mechanisms. Springer Berlin Heidelberg.
McFarland, D. (2006). A Dictionary of Animal Behaviour. Oxford University Press.
Miklosi, A. (2007). Dog Behaviour, Evolution, and Cognition. Oxford University Press.
Nelson, R. J. (2006). Biology of aggression. Oxford University Press.
Scott, J. P., & Fuller, J. L. (1965). Genetics and the social behavior of the dog. The University of Chicago Press.
Siegel A, Edinger H (1981): Neural control of aggression and rage behavior. In: Handbook of the Hypothalamus, Vol. 3, Part B, Morgane Pi, Panksepp J eds. New York: Marcel Dekker
Sillar, K. T., Picton, L., & Heitler, W. J. (2016). The neuroethology of predation and escape. Wiley Blackwell.
