Evolutionary Strategies

ESS doves hawks

An evolutionarily stable strategy (ESS) is a strategy that no other feasible alternative strategy can better, provided sufficient members of the population adopt it. The best strategy for an individual depends upon the strategies adopted by other members of the population. Since the same applies to all individuals in the population, a mutant gene cannot invade a true ESS successfully.

Evolutionary biologists imagine a time before a particular trait existed. Then, they postulate that a rare gene arises in an individual and ask what circumstances would favor its spread throughout the population. If natural selection favors the gene, then the individuals with the genotypes incorporating that gene will have increased fitness. A gene must compete with the existing members of the gene pool and resist invasion from other mutant genes to become established in a population’s gene pool.

When considering evolutionary strategies that influence behavior, we envision a scenario in which changes in the genotype result in corresponding changes in behavior. By ‘the gene for sibling care’, we mean that genetic differences exist in the population such that some individuals are more likely to aid their siblings than others. Similarly, by ‘dove strategy,’ we mean that animals exist in the population that do not engage in fights and that pass this trait from one generation to the next.

At first sight, it might seem that the most successful evolutionary strategy will always spread through the population and eventually supplant all others. While this may sometimes be the case, it is far from always being so. Sometimes, it may not even be possible to determine the best strategy. Competing strategies may be interdependent. The success of one depends upon the existence of the other and the frequency with which the population adopts the other. For example, the strategy of mimicry has no value if the warning strategy of the model is not efficient.

Game theory belongs to mathematics and economics, and it studies situations where players choose different actions in an attempt to maximize their returns. It is a good model for evolutionary biologists to approach situations in which various decision makers interact. The payoffs in biological simulations correspond to fitness, comparable to money in economics. Simulations focus on achieving a balance that would be maintained by evolutionary strategies. The Evolutionarily Stable Strategy (ESS), introduced by John Maynard Smith in 1973 (and published in 1982), is the most well-known of these strategies. Maynard Smith used the hawk-dove simulation to analyze fighting and territorial behavior. Together with Harper in 2003, he employed an ESS to explain the emergence of animal communication.

An evolutionarily stable strategy (ESS) is a strategy that no other feasible alternative strategy can better, provided sufficient members of the population adopt it.

The traditional way to illustrate this problem is the simulation of the encounter between two strategies, the hawks and the doves. When a hawk meets a hawk, it wins on half of the occasions, and it loses and suffers an injury on the other half. Hawks always beat doves. Doves always retreat against hawks. Whenever a dove meets another dove, there is always a display, and it wins on half of the occasions. Under these rules, populations of only hawks or doves are not an ESS. A hawk can invade a population made up entirely of doves, and a dove can invade a population of hawks only. Both would have an advantage and would spread in the population. A hawk in a population of doves would win all contests. A dove in a population of hawks would never get injured because it wouldn’t fight.

However, it is possible for a mixture of hawks and doves to provide a stable situation when their numbers reach a certain proportion of the total population. For example, with payoffs as winner +50, injury -100, loser 0, display -10, a population consisting of hawks and doves (or individuals adopting hawk and dove strategies) is an ESS whenever 58,3% of the population are hawks and 41,7% doves; or, alternatively, when all individuals behave at random as hawks in 58,3 % of the encounters and doves in 41,7%.

Evolutionarily stable strategies are not artificial constructs. They exist in nature. The Oryx, Oryx gazella, has sharp, pointed horns, which it uses only in defense against predators and never in contests with rivals. They play the dove strategy. Up to 10% per year of MuskoxOvibos moschatus, adult males die as a result of injuries sustained while fighting over females. They play the hawk strategy.

Peer-to-peer file sharing is a good example of an ESS in our modern society. BitTorrent peers use Tit for Tat strategy to optimize their download speed. Cooperation is achieved when upload bandwidth is exchanged for download bandwidth.

Life is a box of wonder and amazement, isn’t it?

 ____________

Featured image: The traditional way to illustrate Evolutionarily Stable Strategies is the simulation of the encounter between two strategies, the hawk and the dove.

References

Dawkins, R. (1980). Good Strategy or Evolutionarily Stable Strategy. In G. W. Barlow & J. Silverberg (Eds.), Sociobiology: Beyond Nature/Nurture (pp. 331-367). Westview Press.
https://doi.org/10.4324/9780429306587-14.

Maynard Smith, J. (1972). Game Theory and the Evolution of Behavior. In R. Lewontin (Ed.), On Evolution (pp. 202–223). Edinburgh: Edinburgh University Press. ISBN: 978-0-85224-248-1.

Maynard Smith, J., & Parker, G. A. (1976). The logic of asymmetric contests. Animal Behaviour, 24(1), 159–175. https://doi.org/10.1016/S0003-3472(76)80110-8

Maynard Smith, J. (1982). Evolution and the theory of games. Cambridge: Cambridge University Press. https://doi.org/10.1017/CBO9780511806292

Life’s All About Food And Sex

Pandas at the Chiang Mai Zoo in northern Thailand.

To offer food to females in exchange for sex works well for most males in various species, except when one eats too much of it. At the Chiang Mai Zoo in Northern Thailand, the male panda, is apparently too fat to have sex and his partner, the female Lin Hui, has lost interest. Zoo keepers have done everything to spice up their sex life including showing them movies of other pandas having sex!... (photo from Chiang Mai Zoo).

The other day I went to my favorite bar (and yes, of course it’s Irish) to drink a couple of beers, play some pool and have a bit of fun. The regulars, my mates, are an eclectic mix of professions, trades, ages, economic status, ethnic backgrounds and sexual orientations, all with very different interests in life. Mostly, we just have fun, drink beers and martinis, play pool, discuss football and holidays, complain about how everything got to be so expensive and the incompetence of politicians, and we laugh at a good as well as a bad joke. Sometimes, someone throws in a kind of provocation, a more complex question.

“Cheers, mate!” someone shouts to me from across a table. “You’re a biologist, so you may be able to answer my question for the day: what’s life all about?”

Fruit Fly Boozing

Sex-deprived fruit fly males drink alcohol four times more than others (photo from Geekologie).

“Cheers to you too, mate. You can’t ask a thing like that. That’s not a bar question,” I say. “But, no problem there. Life is all about food and sex,” I add, taking a slug of my wonderfully cold beer and confirming my view that the first beer always tastes the best.

“Hey, I’m asking a serious question,” he protests, “gimme a serious answer!”

“I’m giving you a serious answer. Everything living organisms do is to get either food or sex. Food is a great thing. Firstly, it is necessary to survive and you need to survive in order to have sex, because, if you’re dead, you can’t have sex. Secondly, females in particular love food because they need food to survive, so they can have sex, so they can have progeny; and their progeny needs food, lots of food.”

“Maybe for other animals,” he argues. “But for us humans, there’s more to life than food and sex. What about science, for one?”

“Very simple—science is a means to an end. Why do you think there are many more male scientists than female? Because they need to invent easy ways to get food to give to females, because the females then get all crazy about them and they have sex. Then, they get more progeny who need more food, which implies more science, more sex…”

“You’re far out, mate, we’re more than that. We have a soul, we produce great art!”

“Most good art is produced by unhappy males. How often do  you hear of a great, happy artist? Do you know why they are unhappy? Because they don’t get the sex they want. That’s why they produce art. Females like beauty because the more beautiful sons or daughters they have, depending on the species, the more grandchildren they will have. Also, artists are normally safe, they are sensitive and it is unlikely they will kill their progeny. So, males produce all the art they can to impress the females so they have sex with them. Then, they get more progeny, and the progeny needs more food, which…”

“OK, I got it,” he says, “artists are sensitive, but what about power?  I guess you’ll say it’s another way of getting sex.”

“You’re right. You’re a quick learner. Powerful males can in theory provide better for their progeny so females like powerful males. For the males, this is good news because if they don’t have a clue about art, they can always try to become rich or powerful, which are basically the same thing. Power means more sex because progeny that are well provided for survive longer, have more sex and have their own progeny, which means grandchildren. This means they need more food, more science…”

“What if I’m not good at art or at the power game?”

“Then, mate, you are in deep s… in terms of sex, but don’t worry, it happens to most males in most species. You can always bluff. Most males do.”

“Well, that’s maybe why I’m here drinking with my mates…”

“Could be. Fruit fly males deprived of sex drink four times more than their mates that have sex.”

“You’re kidding me!” he exclaims.

“No, I’m not, that’s scientific proven. It’s all a question of maintaining the levels of a neuropeptide in the brain and if you can’t have sex, booze seems to do it—for fruit files, that is. Fruit flies don’t play pool though, so no worries about that,” I say.

“Doesn’t sound fair to me,” he replies, “but who programmed this bloody thing anyway? Don’t tell me it was…”

“Nobody. Genes have only one goal, which is to reproduce, no matter what genes we’re talking about. It’s all about surviving and reproducing, eating and copulating. It’s like an algorithm, a very simple one indeed.”

“Not that I’m complaining, mate, not too much anyway, but it does bother me. It seems like the females control everything.”

“They do. In most species they choose the males. Virtually all females will mate and reproduce. For the males, it’s a lot more difficult. Competition is fierce and females are picky. Many males never get a chance. That’s why they have to trick the females with all their cunning, but food is the best and most direct way. Males try desperately to improve their chances, in some species by means of attractive exteriors, in others by appearing powerful. Basically, it’s all a bluff to impress the females.”

“So, the females are picky so they can get the best progeny and the best progeny of the progeny. Did I get that right?’

“Too right, mate. Males bluff, but females get better and better at calling their bluff because their main concern is to produce good progeny.”

“OK, I understand that and I can see what the females get, but one things beats me: what about the males, what do they get?”

“Sex.”

Have a beautiful day!

R-

Dominance—Making Sense of the Nonsense

Abstract

This paper challenges the prevailing confusion and debate around the concept of dominance in dogs and other social animals, elucidating dominance from an ethological and evolutionary perspective. It argues that dominance is an observable, behavioral characteristic shared across species, not merely a human-imposed social construct. It defines dominance and submission as dynamic, situational behaviors aimed at gaining or temporarily maintaining access to resources without injury, distinct from aggression. Hierarchies, where they exist, are Evolutionarily Stable Strategies (ESS) that arise from individuals’ dominant or submissive behavior, adapted to the context. The paper emphasizes the importance of accurate, pragmatic definitions to avoid misunderstandings and advocates for viewing relationships—e.g., human-dog ones—as partnerships built on cooperation rather than rigid hierarchies. Dominance behavior, properly understood, is instrumental in resolving social conflicts and maintaining group stability, rather than being a fixed rank or power status. The paper calls for clear, science-based reasoning rather than emotional or ideological dismissals of dominance.

Roger Abrantes and Wolf
A relationship is a natural thing! (Photo by Monty Sloan)

Introduction

Stable and profitable relationships are not built in the long run through a series of dominant and submissive displays. Instead, these behaviors are necessary for resolving inevitable social conflict. Both humans and dogs (and wolves, of course) form relationships based on the need for partnership in overcoming common problems related to survival and, preferably, achieving an acceptable level of comfort. Relationships are not founded on hierarchies; however, hierarchies do exist and play a significant role in certain circumstances—for humans as well as dogs (and wolves, of course)—sometimes more, sometimes less, and sometimes not at all (Schenckel, 1947; Zimen, 1976; Mech, 1999; Chase et al., 2002).

Illustration showing the possible combinations of aggressive, fearful, dominant and submissive behavior in social canines (From "Dog Language" by Roger Abrantes, illustration by Alice Rasmussen). Copyrighted illustration.
Illustration showing the possible combinations of aggressive, fearful, dominant, and submissive behavior in social canines (From “Dog Language” by Roger Abrantes, illustration by Alice Rasmussen). Copyrighted illustration.

In everyday language, dominance refers to having “power and influence over others.” It means supremacy, superiority, ascendancy, preeminence, predominance, mastery, power, authority, rule, command, and control (Cambridge Dictionary; Merriam-Webster). The term has so many meanings and connotations that we cannot simply pick a dictionary definition and employ it as a scientific term in the behavioral sciences. We need to define terms accurately to avoid misunderstandings, meaningless discussions, and nonsensical claims. Unfortunately, the scientists who use the term dominance and its derivatives (as well as those who reject it) have not satisfactorily defined it, thereby contributing to the current confusion about the nature and function of dominant behavior (Drews, 1993).

I intend to remedy this by:

(1) demonstrating that dominance is an observable characteristic of behavior, not a trait of an individual;

(2) establishing that it refers to one and the same class of behaviors independent of species;

(3) presenting a precise, pragmatic, and verifiable definition of the term, which is compatible with evolutionary theory and our body of biological knowledge;

(4) arguing that, even though it is true that a good (in terms of being profitable and stable) relationship does not rely on continuous displays of dominance/submission from the same individuals toward the same other individuals, that does not imply that dogs cannot show dominant behavior.

Denying that dominant behavior exists in dogs has become a popular argument to defend the claim that we must not ‘dominate’ our dogs.

Indeed, the discussion on dominance has run away with us. There is only one thing more absurd and futile than attempting to prove that dominant behavior exists, and that is trying to prove that it does not. In the following, I shall commit the first of these futile acts.

Wolf Pack
In a stable pack, wolves mostly display dominant and submissive behavior and seldom aggressive and fearful behavior (photo by Monty Sloan).

On the similarities and differences of species

It is absurd to argue that dominance (as an attribute or property) does not exist when we have so many words for it, varying by context and nuance. If it didn’t exist, neither would all these terms (Wittgenstein, 1953; Millikan, 1984; Saussure, 2011). The numerous synonyms and connotations suggest that while the term is difficult to define, we have recognized a behavioral property whose characteristics are distinct enough from others to warrant classification in a specific category and a name. Whether the chosen names are suitable or well-defined is a separate issue and does not affect the behavior itself. We can argue that this attribute (dominance) has been observed and that (1) it only applies to certain human relationships, or that (2) it applies to certain relationships among humans as well as some other animal species. The second option seems more appealing, given that it is unlikely that a specific condition exists in only one species. That would contradict everything we know about the relatedness and evolution of species (Darwin, 1871; Mayr, 1982).

However, there is nothing implausible about stating that the term does not apply to the behavior of a particular species. On the contrary, two species that diverged from a common ancestor billions of years ago evolve and develop their own characteristics, ultimately differing from one another and from their common ancestor. By the same token, closely related species, which diverged from a single common ancestor a few thousand years ago, will exhibit various characteristics similar to or equal to those of the common ancestor and to one another. Some species share many common attributes in terms of phenotype, genotype, and behavior (which is a phenotype); others share fewer, and some none at all. It all depends on their shared ancestry and their adaptation to the environment (Dobzhansky, 1973; Futuyma, 1998).

English: Saarloos Wolfdog male Polski: Samiec ...
Wolf-dog hybrid (Image via Wikipedia).

Humans and chimpanzees (Homo sapiens and Pan troglodytes) diverged from a common ancestor about six to seven million years ago (maybe up to 13), so we can expect them to have fewer common attributes than wolves and dogs (Canis lupus lupus and Canis lupus familiaris), which only diverged from a common ancestor about 15 to 20 thousand years ago and definitely no more than 100 thousand years ago according to recent studies (Vilà et al., 1997; Savoilanen et al., 2002; Kumar et al., 2005)

The DNA of humans and chimpanzees differs more than that of wolves and dogs (which is almost identical except for a few mutations). Humans cannot interbreed with chimpanzees (Disotell, 2006; Presgraves & Yi, 2009); wolves and dogs can interbreed and produce fertile offspring. Thus, humans and chimpanzees are two entirely distinct species, whereas wolves and dogs are two subspecies of the same species (Wayne & Ostrander, 1999; Nowak, 2003).

Considering these facts, we can expect wolves and dogs to share a significant number of similarities, which indeed they do, not only physically but also behaviorally—and any layman would attest to that. Their similarities at certain levels enable them to mate, produce fertile offspring, and communicate effectively (Zimen 1981). Nobody questions that wolves and dogs share an extensive repertoire of communication behaviors, and rightly so, as multiple observations have confirmed that they communicate well (Feddersen-Petersen, 2004). Their facial expressions and bodily postures are remarkably similar. Dogs (most breeds) and wolves share similar facial musculature, although domestication has produced some structural differences in dogs that facilitate communication with humans (Coppinger & Coppinger, 2001), and dogs appear to have some limitations in producing the same range of affective facial expressions as wolves (Miklósi et al., 1998). However, these are relatively minor differences between the two subspecies, significantly smaller than the cultural differences observed among humans from geographically separated settlements.

If wolves and dogs can communicate, it suggests that the fundamental elements of their languages must be the same or very similar. That indicates that, despite evolving in seemingly different environments, they have preserved the essential aspects of their genotypic characteristics. There could be several reasons for this: (1) the common genotypes are vital to the organism, (2) the environments were not so crucially distinct after all, (3) evolution needs more time and more selective conditions (since it acts on phenotypes) for the genotypes to begin to differ radically.

Point (1) above means that there are more ways not to be alive than there are ways to be alive. In other words, evolution needs time to come up with different, viable life forms (Darwin, 1859; Mayr, 1963; Futuyma, 1998). Point (2) indicates that although wolves and (pet) dogs currently live in entirely different environments, the phenomenon is still too recent. It is only in the last century that dogs have become so over-domesticated. Before that, they were our companions, domestic animals that retained a considerable degree of freedom and relied (mainly) on the same successful selective factors as always. They were still not pets, and breeding was not predominantly controlled by human selection. Point (3) suggests that, given enough time—a million years or so—we may eventually have two entirely distinct species: wolves and dogs. By then, they will not mate, will not produce fertile offspring, and may exhibit completely different characteristics. Then, we may even change the domestic dog’s scientific name from Canis lupus familiaris to Canis civicus, or Canis homunculus. However, we are not there yet!

On similarities and differences

Recent trends suggest that “dominant behavior” does not exist in dogs (please check the internet), which poses some serious problems. There are two ways to argue in favor of this line of thinking. The first is to dismiss “dominant behavior” outright, which is absurd, as, for the aforementioned reasons, the term does exist, we have a rough understanding of what it means, and we use it in conversation. It must, therefore, refer to a class of behaviors that we have observed (Wittgenstein, 1953; Millikan, 1984; Saussure, 2011). The second way of arguing is to claim that wolves and dogs are entirely different and, therefore, even though we can apply the term to describe wolf behavior, we cannot use it to describe dog behavior. If they were completely different, the argument could be valid, but they are not, as we have seen. On the contrary, they are very similar, and, therefore, this argument is invalid (Copi, 1999).

A third alternative is to propose a brand new theory to explain how two such closely related species, as the wolf and the dog (actually a subspecies), can have developed in such a short period (thousands of years) with so many radically different characteristics in one single aspect, but not in others. This would amount to a massive revision of our entire body of biological knowledge, with implications far beyond wolves and dogs—an alternative I find unrealistic (Bromham, 2009).

That said, when comparing different species’ behavioral strategies, including social structures, we must be careful not to blindly extrapolate across species without regard for the particular ecology and evolution of each species. Comparing involves finding similarities and differences. For example, wolf societies, although similar to stray and feral dog societies in many respects, also (as expected) differ radically in others. Even within the same subspecies—wolves and dogs, respectively—societies vary slightly depending on ecological factors, such as the age of their members, pack size, and prey availability (Zimen, 1976 and 1982; Abrantes, 1997; Mech, 1999; Cafazzo et al., 2010).

Appeal to consequences

A far more appealing approach, it seems to me, is to analyze the concepts we use and define them properly. This would allow us to use them meaningfully when dealing with different species without running into incompatibilities with the entire body of science.

An accurate definition of “dominant behavior” is important because the behavior it describes is crucial to the survival of a particular type of individual, as we shall see.

Dismissing the existence of facts that underlie a term simply because that term is ill-defined or politically incorrect—meaning it doesn’t serve our immediate goals—seems to me to be a flawed approach. That is known as the appeal to consequences fallacy (argumentum ad consequentiam) and represents an error in reasoning (Copi 1999). Dominant behavior exists, but it is poorly defined (if defined at all). Most discussions involving dominant behavior are meaningless because neither party knows precisely what the other is referring to. However, we don’t need to throw the baby out with the bath water!

Definitions

Therefore, I propose that we establish precise definitions of dominant behavior and identify and define the factors necessary to understand what it is, what it is not, how it evolved, and how it functions. Thus:

Dominant behavior (or dominantness) is quantitative and quantifiable behavior displayed by an individual with the function of gaining or maintaining temporary access to a particular resource on a particular occasion, versus a particular opponent, without either party incurring injury. If any party is injured, the behavior is aggressive, not dominant. Its quantitative characteristics range from slightly self-confident to overtly assertive.

Dominant behavior is situational, individual, and resource-related. One individual displaying dominant behavior in a specific situation does not necessarily exhibit it on another occasion, either toward another individual or toward the same individual in a different situation.

Resources are what an organism considers to be life necessities, e.g., food, a mating partner, or a patch of territory. The perception of what an animal finds a resource is both species- and individual-related.

Aggressiveness (aggressive behavior) is behavior directed toward eliminating competition, while dominance (social aggressiveness) is behavior directed toward eliminating competition from a mate.

Mates are two or more animals that live closely together and depend on one another for survival. Aliens are two or more animals that do not live closely together and do not depend on one another for survival. Please note that I’m using the term ‘mate’ as it is commonly used in the UK, Australia, and New Zealand, without any sexual connotations.

Dominant behavior is particularly important for social animals that need to cohabit and cooperate to survive. Therefore, a particular social strategy evolved with the function of dealing with competition among mates, whilst conferring the greatest benefit at the least cost (Abrantes, 1997).

Animals display dominant behavior through various signals: visual, auditory, olfactory, and/or tactile.

While fearfulness (fearful behavior) is behavior directed toward the elimination of an incoming threat, submissiveness (submissive behavior), or social-fearfulness, is behavior directed toward the elimination of a social threat from a mate, i.e., losing temporary access to a resource without incurring injury.

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. 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.

Animals show submissive behavior through various signals: visual, auditory, olfactory, and/or tactile.

Dynamics of Behavior and Evolutionarily Stable Strategies

Persistent dominant or submissive behavior from the same individuals toward the same other individuals may or may not result in a temporary hierarchy of a particular configuration, depending on species, social organization, and environmental circumstances. In stable groups confined to a defined territory, temporary hierarchies will develop more readily. In unstable groups under changing environmental conditions or in undefined or non-established territories, hierarchies will not develop. Hierarchies, or rather the strategies involved, are Evolutionarily Stable Strategies (ESS), which are always slightly unstable, swinging forth and back around an optimal value, depending on the number of individuals in the group and the strategy each individual adopts at any given time (Maynard Smith & Price, 1973; Hines, 1987). Hierarchies are not necessarily linear, although in small groups and over time, non-linear hierarchies tend to become more linear (Noë et al., 1980; Chase et al., 2002).

Some individuals have a stronger tendency to exhibit dominant behavior, while others tend to show submissive behavior. That may depend on their genetic makeupearly learningmaturityexperiences, etc. There is no single factor that determines this; rather, it is a complex interplay of factors. Let us call this a natural tendency; this is not to say it is not modifiable. It is a fact that some individuals are more assertive than others, while others are less so. Neither is ‘good’ nor bad’ in a moral sense, simply more or less advantageous, depending on context. It is all a question of costs and benefits (Real, 1991; Krebs & Davies, 1993). In one-to-one encounters, all things being equal, individuals are more likely to adopt the strategy they feel most comfortable with, thereby maintaining their history of predominantly displaying either dominant or submissive behavior.

In larger groups, individuals tend to play roles that they feel most comfortable with. However, this can change due to the accidental makeup of the group. Imagine a group with a large proportion of individuals that are prone to showing submissive rather than dominant behavior, and with only a few members showing the opposite tendency. In this scenario, an individual with a tendency to primarily exhibit submissive behavior would be more likely to gain access to resources by adopting more dominant behavior. Success breeds success, and progressively, this individual, who tends to display submissive behavior, increasingly opts for a dominant strategy. If the scenario prompts one individual to change its preferred strategy, then others will also have the same opportunities. The number of individuals exhibiting dominant behavior will increase, but only to a point, as the group cannot sustain too many individuals adopting a dominant strategy. To avoid the risk of injury, it will eventually be more advantageous to adopt or revert to a submissive strategy, depending on the incurred benefits and costs (Maynard Smith & Price, 1973; Houston & McNamara, 1991; McNamara et al., 1991).

Therefore, the number of dominant and submissive individuals in a group (i.e., individuals adopting one of the two strategies as their preferred strategy) depends not only on individuals’ natural tendencies but also on the proportions of behavioral strategies within the group. Whether it pays off to play a dominant or a submissive role is ultimately a function of benefits and costs, as well as the number of individuals who adopt one particular strategy.

Understanding the relationship between dominant and submissive behavior as an ESS (Evolutionarily Stable Strategy) opens up exciting perspectives and could help explain the behavior adopted by any given individual at any given time. An individual will learn to display submissive behavior toward those who act more dominantly and display dominant behavior toward those who act more submissively. That means that no individual always behaves dominantly or submissively as a principle; instead, it all depends on the opponent’s choice of strategy and, of course, the value of the potential benefits and estimated costs (Maynard Smith, 1982; Gross, 1996; Dugatkin & Reeve, 1998).

As a corollary, hierarchies (when they exist) will always be slightly unstable, depending on the strategies adopted by individuals in the group; and will not be linear, except in small groups or subgroups (Chase, 2002).

In the opinion of this author, the mistake we have committed hitherto has been to regard dominance and submission (or, more correctly, dominantness and submissiveness) as more or less static. We haven’t taken into account that these behavioral characteristics, like all phenotypes, are constantly under the scrutiny and pressure of natural selection. They are adaptive, highly variable, and highly quantitative and quantifiable (Fisher, 1930; Lande, 1976; Roff, 1997)

As such, dominance and submission are dynamic features that depend on various variables, a view that is compatible with the ontogeny of behavior at the individual level, including the interaction of genetic predispositions and environmental factors, learning processes, adaptations, and, not least, the broader framework of evolutionary theory.

Dominance and submission are beautiful mechanisms from an evolutionary perspective. They enable (social) animals to live together and survive until they reproduce and pass their (dominant and submissive behavior) genes to the next generation. Without these mechanisms, we wouldn’t have social animals such as humans, chimpanzees, wolves, and dogs, among others.

Suppose an animal resolved all inter-group conflicts with aggressive and fearful behavior. It would be exhausted when subsequently compelled to find food, a mating partner, or a safe place to rest or take care of its progeny (all of which decrease the chances of its own survival and that of its genes). Thus, the alien and mate strategy originated and evolved (see my definitions above). It is impossible to fight everybody all of the time, so a mate is confronted using energy-saving procedures.

Submissive and dominant behavior also control population density, since they rely on individual recognition. The number of individuals an animal can recognize is limited by constraints on brain size and information-processing capacity (Dunbar, 1998; Cheney & Seyfarth, 1990). If this number exceeds a certain level, recognition becomes inefficient and hinders the alien/mate strategy; fearful/aggressive displays then replace submissive/dominant behavior.

The strategy of submission is sound. Instead of vainly engaging in a desperate fight, waiting may prove more rewarding. By employing pacifying and submissive behavior strategies, subordinates often shadow dominantly behaving animals and gain access to vital resources. By exhibiting submissive behavior, they retain their membership in the group, which also confers them several advantages—particularly defense against rivals.

Hierarchies

Hierarchies work because a subordinate will often move away, showing typical pacifying behavior, without too obvious signs of fear. Thus, the higher-ranking animal may displace a lower-ranking animal when feeding or at a desirable site. Hierarchies in nature are often subtle, making them difficult for an observer to decipher. The reason for this subtlety is the raison d’être of the dominance-submission strategy itself: the lower-ranking animal (adopting the submissive strategy) generally avoids conflicts, and the higher-ranking (adopting the dominance strategy) is not too keen on running into skirmishes either.

Fighting involves a certain amount of risk and can lead to serious injury or even death. Evolution, therefore, tends to favor the development of mechanisms that restrain the intensity of aggressive behavior. Most species exhibit clear signals indicating acceptance of defeat and an end to combat before injury occurs (Matsumura & Hayden, 2006; Natarajan & Caramaschi, 2010).

Sign stimuli, a venerable ethology term, designate specific stimuli that trigger instinctive behavior sequences (Tinbergen, 1951 and 1952). For infants, recognizing these sign stimuli is crucial for their survival immediately after birth. After mastering these essential life-saving responses, the most relevant lesson a social youngster learns is compromise. This skill is vital to maintaining a group’s cohesion and fitness. Natural selection has proven this, favoring those individuals who develop the particular behaviors that enable them to stay together when necessary for their survival and reproduction. In contrast, solitary predators, for example, need no such social traits as they have evolved alternative strategies to ensure their survival and reproduction.

Learning to be social

Learning to be social involves mastering the art of compromise. Social animals spend significant amounts of time together, making conflicts inevitable. It is therefore crucial for them to develop efficient mechanisms to manage hostilities. Limiting aggressive and fearful behavior through inhibition and ritualization is only partially efficient (and safe). For highly social, potentially aggressive animals, it is crucial to have more advanced mechanisms in place to prevent injury. Inhibited aggression is still a form of aggression—it’s like playing with fire on a windy day. It works reasonably well for less social or less potentially aggressive animals. However, animals that are both highly social and potentially highly aggressive need better strategies to ensure that the benefits of group living outweigh its costs (Alexander, 1974; Wilson, 1975; Creel & Creel, 1995).

In the long run, relying on aggression and fear to constantly address trivial problems would become too dangerous and exhausting. Animals exhibit signs of pathological stress when they face persistent threats or are repeatedly forced to attack others. That suggests that social predators require mechanisms beyond mere aggressiveness and fearfulness to resolve social animosities. I suggest that, through the ontogeny of aggressiveness and fearfulness, social animals have also developed two other equally important social behaviors. If the function of aggression is to convey “go away, drop dead, never bother me again,” then the function of social-aggression is to communicate “go away, but not too far, or for too long.” Similarly, social fear expresses “I won’t bother you if you don’t hurt me,” whereas existential fear leaves no room for compromise—“It’s either you or me.”

The key difference between the two types of aggressive behavior lies in their functions. Aggressiveness is directed toward an alien, whereas social aggressiveness is directed toward a mate. Conversely, fearfulness and social fearfulness pertain to the alien and the mate. These are qualitative distinctions that justify the coining of new terms, hence dominance (dominantness) and submission (submissiveness).

What implications does all this have on how we understand and connect with our dogs?

We, as all highly social animals, display dominant behavior (i.e., self-confident, assertive, firm, forceful) as well as submissive behavior (i.e., insecure, accepting, consenting, yielding) depending on many factors including our state of mind, social position, available resources, health status, and the presence of a particular opponent—humans as well as dogs (and wolves, of course). There’s nothing inherently wrong with exhibiting either behavior, except when we display dominant behavior where it would be more beneficial to show submissive behavior, or the other way around. Sometimes we may act more dominantly or submissively, and other times, less so. Our tendencies to act dominantly or submissively vary widely, influenced by numerous factors, since these behaviors are highly quantitative and quantifiable. There is no single, universally correct strategy. Like all Evolutionarily Stable Strategies (ESS), the appropriate behavioral strategy depends on the costs and benefits incurred and on the strategies adopted by others. One strategy cannot exist without the alternative(s). Each strategy keeps the others honest (Maynard Smith, 1982).

Stable and profitable relationships do not develop in the long run through a series of dominant and submissive displays. Instead, these behaviors are necessary for resolving inevitable social conflict. Both humans and dogs (and wolves, of course) form relationships out of a need for partnership in overcoming shared problems related to survival and, preferably, achieving an acceptable level of comfort. Relationships are not necessarily built on hierarchies, but hierarchies do exist and they play a crucial role in certain circumstances—for humans as well as dogs (and wolves, of course)—sometimes more, sometimes less, and sometimes not at all (Chase et al., 2002).

Epilogue (a kind of)

We establish a positive relationship with our dogs based on partnership. Our dogs provide us with a sense of accomplishment we often can’t find elsewhere. In return, they rely on us for essential needs such as food, protection, healthcare, a safe environment, and companionship, as they are social animals. It’s too hard to be a little dog all alone out there in the big world! Sometimes, in this relationship, one of the parties resorts to dominant or submissive behavior, and there’s nothing wrong with that, as long as they do not both show the same behavior at the same time. If both resort to the same behavior, they have a problem: they either run into a conflict that they will usually resolve without injury (the beauty of the dynamics of dominance and submission), or one of them will have to get their act together and find their bearings for both.

A good relationship with our dogs does not involve any mysterious mechanisms. It’s basically the same as in all good relationships, whilst taking into account the particular characteristics of the species and individuals involved. We need no new terms. We need no new theories to explain it. We aren’t, after all, that special, nor are our dogs. We are all made from the same fundamental components: phosphate, deoxyribose, and four nitrogen bases (A, T, G, C) (Alberts et al., 2002).

All we need are clear definitions and a more rational, less emotional approach. Use your heart to enjoy life with other living beings (including your dog), and your reason to explain it (if you need to)—not the other way around. If you don’t like my definitions, feel free to propose better ones (with more advantages and fewer disadvantages), but don’t waste your time, or anyone else’s, on meaningless discussions and knee-jerk reactions. Life is precious, and like with a tasty cake, every moment you waste is like one bite of that yummy cake that you’ve devoured without even realizing it.

That’s how I see it—enjoy your cake!

R~

Related articles

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Thanks to Simon Gadbois (merci), Tilde Detz (tak), Victor Ros (gracias), Sue McCabe (go raibh math agate), Parichart Abrantes (ขอบคุณครับ), and Anna Holloway (thank you) for conversations, exchange of messages, and suggestions to improve this paper. Any remaining flaws are mine, not theirs.

Note from the author: In September 2025, I have edited a few paragraphs to correct typos and improve clarity and conciseness.