Laughter is the shortest distance…



We laugh, but we are not the only ones.

As you have figured out by now, I enjoy finding proof that humans are not that different from other forms of life. We share many characteristics with the other living creatures on our blue planet. Today, I have one more example for you—laughter.

Laughing is an involuntary reaction in humans consisting of rhythmical contractions of the diaphragm and other parts of the respiratory system. External stimuli, like being tickled, mostly elicit it. We associate it primarily with joy, happiness, and relief, but fear, nervousness, and embarrassment may also cause it. Laughter depends on early learning and cultural factors.

The study of humor and laughter is called gelotology (from the Greek gelos, γέλιο, meaning laughter).

Chimpanzees, gorillas, bonobos, and orangutans display laughter-like behavior when wrestling, playing or tickling. Their laughter consists of alternating inhalations and exhalations that sound to us like breathing and panting.

Rats display long, high frequency, ultrasonic vocalizations during play and when tickled. We can only hear these chirping sounds with proper equipment. They are also ticklish, as are we. Particular areas of their body are more sensitive than others. There is an association between laughter and pleasant feelings. Social bonding occurs with the human tickler, and the rats can even become conditioned to seek the tickling.*

A dog’s laughter sounds similar to a regular pant. A sonograph analysis of this panting behavior shows that the variation of the bursts of frequencies is comparable with the laughing sound. When we play this recorded dog-laughter to dogs in a shelter, it can contribute to promoting play, social behavior, and decrease stress levels.*

Victor Borge once said, “Laughter is the shortest distance between two people.” Maybe, it is simply the shortest distance between any two living creatures.


* Panksepp & Burgdorf, 2003, ‘Laughing’ rats and the evolutionary antecedents of human joy?; Simonet, Versteeg & Storie, 2005, Dog-laughter: Recorded playback reduces stress related behavior in shelter dogs.

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"Ethology" by Roger Abrantes

If animal behavior fascinates you, you will enjoy "Ethology—The Study of Animal Behavior in the Natural Environment," the book and course by ethologist Roger Abrantes.
Enrolling for this course puts you in direct contact with the author to whom you can pose any question while you complete your coursework. Click here to read more and enroll.

How Wolves Change Rivers


The wolves changed the rivers of the Yellowstone. Picture by photographer Ronan Donovan, NG.


In 1926, there were no longer wolves in Yellowstone, once the natural habitat of this species. Between 1977 and the re-introduction in 1995, we have reliable reports of wolves being seen throughout the park. Most of them were either lone wolves or pairs, probably only transiting. Finally, in 1995, grey wolf packs were reintroduced in the Lamar Valley of Yellowstone National Park and Idaho.


“How Wolves Change Rivers” produced by Sustainable Man and narrated by George Monbiot.


Before the extirpation, the wolves living within the park belonged to the subspecies Northern Rocky Mountains wolf, Canis lupus irremotus. The reintroduced species of 1995 belong to the subspecies Mackenzie Valley wolf, Canis lupus occidentalis.

The reintroduction of the wolves has shown a greater impact on the biodiversity of the Yellowstone than anticipated.

The wolves’ predation on the elk population, until then unchallenged, produced a significant increase of new-growth in various plants. Aspen and willow trees, previously grazed by the elks more or less at will, got suddenly a chance to grow. With the presence of the wolves, the elks stopped venturing into deeper and for them dangerous thickets where they could easily be surprised. They began to avoid areas of low visibility, which would increase the chances of wolf attacks.

The elks began avoiding open regions such as valley bottoms, open meadows and gorges, where they would be at a disadvantage in case of an attack from a wolf pack. William J. Ripple and Robert L. Bestcha dubbed this process top-down control. In ecology, top-down control denotes that top predators regulate the lower sections of the trophic pyramid. In other words: a top predator controls the structure or population dynamics of a particular ecosystem.

With new vegetation growing and expanding came subtle changes in the waterways running through the park. That had an impact on other species as well. Various bird species came back to Yellowstone with the increased number of trees. The beaver, previously extinct in the region, returned to the park. Their dams across the rivers attracted otters, muskrats, and reptiles.

Probably due to the wolves keeping the coyote populations at bay, the red fox got suddenly a chance to survive because the number of rabbits and mice grew considerably. The raven, always the wolf follower, came back to the park as well, now able to feed on the leftovers of the wolves.

The wolves changed the rivers, in as much as they readdressed the lost balance within the region, one we had created when we exterminated them. With a better balance between predator and prey, top meat eaters and top grazers, came the possibility for other species to thrive. With the increased vegetation growth, erosion decreased and the river banks stabilized.

Every time we produce drastic changes in nature, we interfere deeply with the whole eco-system.

Nature is indeed a beautiful act of balance.


References and further reading

"Ethology" by Roger Abrantes

If animal behavior fascinates you, you will enjoy "Ethology—The Study of Animal Behavior in the Natural Environment," the book and course by ethologist Roger Abrantes.
Enrolling for this course puts you in direct contact with the author to whom you can pose any question while you complete your coursework. Click here to read more and enroll.

The 20 Principles of Genes, Environment and Breeding

Golden with puppies.

Hereditary traits are inherited equally from both parents. However, the mother will have more influence on the puppies’ behavior than the father because she spends more time with them.


Genes code for the traits an organism will show, physical as well as behavioral, but genes are not all. The environment of that organism also plays a crucial role in the way some of its genes will express themselves.

Genes play a large role in the appearance and behavior of organisms. Phenotypes (the appearance of the organism) are determined, in various degrees, by the genotype program (the sum of all genes) and the interaction of the organism with the environment. Some traits are more modifiable by environmental factors, others less. For example, while eye color is solely determined by the genetic coding, genes determine how tall an individual may grow, but nutritional, as well as other health factors experienced by that organism, determine the outcome. In short: the environment by itself cannot create a trait, and only a few traits are solely the product of a strict gene coding.

The same applies to behavior. Behavior is the result of the genetic coding and the effects of the environment on a particular organism. Learning is an adaptation to the environment. Behavioral genetics studies the role of genetics in animal (including human) behavior. Behavioral genetics is an interdisciplinary field, with contributions from biologygeneticsethologypsychology, and statistics. The same basic genetic principles that apply to any phenotype also apply to behavior, but it is more difficult to identify particular genes with particular behaviors than with physical traits. The most reliable assessment of an individual’s genetic contribution to behavior is through the study of twins and half-siblings.

In small populations, like breeds with a limited number of individuals, the genetic contribution tends to be magnified because there is not enough variation. Therefore, it is very important that breeders pay special importance to lineages, keep impeccable records, test the individuals, and choose carefully, which mating system they will use. Failure to be strict may result in highly undesirable results in a few generations with the average population showing undesired traits, physical as well as behavioral.

We breed animals for many different purposes. Breeding means combining 50% of the genes of one animal (a male) to 50% of the genes of another animal (a female) and see what happens. We can never choose single genes as we wish and combine them, so we get the perfect animal, but knowing which traits are dominant, which are recessive, and being able to read pedigrees helps us.


Siberian Husky puppies.

Litter mates share on average 50% common genes, but only on average. Each got at random 50% of its genes from the male (father) and 50% from the female (mother), but not necessarily the same 50% from each (Photo by


Here are some guidelines for breeding (inspired by “20 Principles of Breeding Better Dogs” by Raymond H. Oppenheimer). The objective of the following 20 principles is to help breeders strive for a healthy and fit animal in all aspects, physically as well as behaviorally.

1. The animals you select for breeding today will have an impact on the future population (unless you do not use any of their offspring to continue breeding).

2. Choose carefully the two animals you want to breed. If you only have a limited number of animals at your disposition, you will have to wait for the next generation to make any improvement. As a rule of thumb, you should expect the progeny to be better than the parents.

3. Statistical predictions may not hold true in a small number of animals (as in one litter of puppies). Statistical predictions show accuracy when applied to large populations.

4. A pedigree is a tool to help you learn the desirable and undesirable attributes that an animal is likely to exhibit or reproduce.

5. If you have a well-defined purpose for your breeding program, which you should, you will want to enhance specific attributes, but don’t forget that an animal is a whole. To emphasize one or two features of the animal, you may compromise the soundness and function of the whole organism.

6. Even though, in general, large litters indicate good health and breeding conditions, quantity does not mean quality. You produce quality through careful studies. Be patient and wait until the right breeding stock is available, evaluate what you have already produced and above all, have a breeding plan that is, at least, three generations ahead of the breeding you do today.

7. Skeletal defects are the most difficult to change.

8. Don’t bother with a good animal that cannot reproduce well. The fittest are those who survive and can pass their survival genes to the next generation.

9. Once you have approximately the animal you want, use out-crosses sparingly. For each desirable characteristic you acquire, you will get many undesirable traits that you will have to eliminate in succeeding generations.


Wolf mother and cubs.

Adult wolves regurgitate food for the cubs to eat. Many dog mothers do the same (Photo by Humans For Wolves).


10. Inbreeding is the fastest method to achieve desirable characteristics. It will bring forward the best and the worst of your breeding stock. You want to keep the desirable traits and eliminate the undesirable. Inbreeding will reveal hidden traits that you may consider undesirable, and want to eliminate. However, be careful, repeated inbreeding can increase the chances of offspring being affected by recessive or deleterious traits.

11. Once you have achieved the characteristics you want, line-breeding with sporadic outcrossing seems to be the most prudent approach.

12. Breeding does not create anything new unless you run into favorable mutations (seldom). What you get is what was there to begin with. It may have been hidden for many generations, but it was there.

13. Litter mates share on average 50% common genes, but only on average. Each one got at random 50% of its genes from the male (father) and 50% from the female (mother), but not necessarily the same 50% from each.

14. Hereditary traits are inherited equally from both parents. Do not expect to solve all of your problems in one generation.

15. If the worst animal in your last litter is no better than the worst animal in your first litter, you are not making progress.

16. If the best animal in your last litter is no better than the best animal in your first litter, you are not making progress.

17. Do not choose a breeding animal by either the best or the worst that it has produced. Evaluate the total breeding value of an animal by means of averages of as many offspring as possible.

18. Keep in mind that quality is a combination of soundness and function. It is not merely the lack of undesirable traits, but also the presence of desirable traits. It is the whole animal that counts.

19. Be objective. Don’t allow personal feelings to influence your choice of breeding stock.

20. Be realistic, but strive for excellence. Always try to get the best you can. Be careful: when we breed animals for special characteristics, physical as well as behavioral, we are playing with fire, changing the genome that natural selection created and tested throughout centuries.


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Canine Ethogram—Social and Agonistic Behavior


Behavior is the response of the system or organism to various stimuli, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary.

Behavior does not originate as a deliberate and well-thought strategy to control a stimulus. Initially, all behavior is probably just a reflex, a response following a particular anatomical or physiological reaction. Like all phenotypes, it happens by chance and evolves thereafter.

Natural selection favors behaviors that prolong the life of an animal and increase its chance of reproducing; over time, a particularly advantageous behavior spreads throughout the population. The disposition (genotype) to display a behavior is innate (otherwise the phenotype would not be subject to natural selection and evolution), It requires, though, maturation and/or reinforcement for the organism to be able to apply it successfully. Behavior is, thus, the product of a combination of innate dispositions and environmental factors. Some behaviors require little conditioning from the environment for the animal to display it while other behaviors require more.

Pictures illustrating canine social and agonistic behavior.

Pictures illustrating canine social and agonistic behavior. For the classification of the behavior, please see ethogram below. Behavior is dynamic (not static). All interpretations are therefore only approximate and as pictures allow.

An organism can forget a behavior if it does not have the opportunity to display it for a period, or the behavior can be extinguished if it is not subject to reinforcement for a period.

Evolution favors a systematic bias, which moves behavior away from a maximization of utility and towards a maximization of fitness.

Social behavior is behavior involving more than one individual with the primary function of establishing, maintaining, or changing a relationship between individuals, or in a group (society).

Most researchers define social behavior as the behavior shown by members of the same species in a given interaction. That excludes behavior such as predation, which involves members of different species. On the other hand, it seems to allow for the inclusion of everything else such as communication behavior, parental behavior, sexual behavior, and even agonistic behavior.

Sociologists insist that behavior is an activity devoid of social meaning or social context, in contrast to social behavior, which has both. This definition does not help us much. All above-mentioned behaviors do have a social meaning and a context unless ‘social’ means ‘involving the whole group’ (society) or ‘a particular number of its members.’ In that case, we should ask how many individuals we need in an interaction to classify it as social. Are three enough? If so, then, sexual behavior is not social behavior when practiced by two individuals, but becomes social with three or more being involved, which is not unusual in some species. We can use the same line of arguing for communication behavior, parental behavior, and agonistic behavior. It involves more than one individual, and it affects the group (society), the smallest possible consisting of two individuals.

Agonistic behavior includes all forms of intraspecific behavior related to aggression, fear, threat, fight or flight, or interspecific when competing for resources. It explicitly includes behaviors such as dominant behavior, submissive behavior, flight, pacifying, and conciliation, which are functionally and physiologically interrelated with aggressive behavior, yet fall outside the narrow definition of aggressive behavior. It excludes predatory behavior.

Dominant behavior is a 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 of the parties incur injury, then the behavior is aggressive and 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 one specific situation does not necessarily show it on another occasion toward another individual, or toward the same individual in another situation.

Dominant behavior is particularly important for social animals that need to cohabit and cooperate to survive. Therefore, a social strategy evolved with the function of dealing with competition among mates, which caused the least disadvantages.

Aggressive behavior is behavior directed toward the elimination of competition while dominance, or social-aggressiveness, is behavior directed toward the elimination of competition from a mate.

Fearful behavior is behavior directed toward the elimination of an incoming threat.

Submissive behavior, or social-fear, is behavior directed toward the elimination of a social-threat from a mate, i.e. losing temporary access to a resource without incurring injury.

Resources are what an organism perceives as life necessities, e.g. food, mating partner, or a patch of territory. What an animal perceives to be its resources depends on both the species and the individual; it is the result of evolutionary processes and the history of the individual.

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 close together and do not depend on one another for survival.

A threat is everything that may harm, inflict pain or injury, or decrease an individual’s chance of survival. A social-threat is everything that may cause the temporary loss of a resource and may cause submissive behavior or flight, without the submissive individual incurring injury. Animals show submissive behavior by means of various signals, visual, auditory, olfactory and/or tactile.

Canine ethogram social agonistics

Canine ethogram for social and agonistic behavior. The colors illustrate that the categories are constructed by us. When a behavior turns into another one is a matter of convention and interpretation (illustration by Roger Abrantes).

The diagram does not include a complete list of behaviors (please, click on the diagram to enlarge it).

PS—I apologize if by chance I’ve used one of your pictures without giving you due credit. If this is the case, please e-mail me your name and picture info and I’ll rectify that right away.

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"Ethology" by Roger Abrantes

If animal behavior fascinates you, you will enjoy "Ethology—The Study of Animal Behavior in the Natural Environment," the book and course by ethologist Roger Abrantes.
Enrolling for this course puts you in direct contact with the author to whom you can pose any question while you complete your coursework. Click here to read more and enroll.

Pacifying Behavior—Origin, Function and Evolution

— by Roger Abrantes

Pacifying behavior (Latin pacificare, from pax = peace and facerefacio = to make) is all behavior with the function of decreasing or suppressing an opponent’s aggressive or dominant behavior or restoring a state of tranquility. There are two ways of classifying pacifying behavior: (1) to include all behaviors with the function of diffusing social conflict, and (2) to restrict it to a particular range within the broader spectrum of conflict decreasing behavior (see diagram below). This author prefers the latter because the broad use of the term in the first option makes it synonymous with conflict decreasing behavior in general, without reference to any particular sub-class of this behavior.

Roger Abrantes And Rottweiler.

This Rottweiler female shows me friendly behavior licking my face and ear. I show that I accept her friendly behavior by turning my face away from her, closing my eyes and mouth and making champing noises. Mostly, dogs show friendly and pacifying behavior to humans as they do to other dogs (photo by Lisa J. Bain).

Pacifying behavior is closely related to friendly behavior (including greeting behavior), insecure, submissive and fearful behavior. In general, the differences between these behavior displays are quantitatively small, but we can classify them separately and qualitatively according to their respective sub-functions. An animal pacifies another using a complex sequence of different behaviors as we can see in the diagram below. An animal very seldom shows a single behavior. Also, the same behavior may achieve different functions depending on its intensity, and the sum of all behaviors displayed at a given moment.

Pacifying behavior did not originate as a deliberate and well-thought strategy to manipulate an opponent. Initially, it was probably just a reflex. Like all phenotypes, it happened by chance and evolved thereafter.

Pacifying Behavior in Canids

Pacifying behavior in dogs: licking own lips, licking and pawing (images by Alanic05 and Colorado Great Pyrenee Rescue Community).

Natural selection favors behaviors that prolong the life of an animal and increase its chance of reproducing; over time pacifying behavior spread throughout the population. Evolution favors a systematic bias, which moves behavior away from the maximization of utility and towards the maximization of fitness.

pacifying behavior animals

Many species show pacifying displays in their behavior repertoire (photos by J. Frisch, AFP and Aleixa).

The origin of pacifying behavior—Animal A facing aggressive opponent B registers (sensory system) B’s behavior, processes it (neurological system) and responds with a behavior. The aggressive animal B registers this behavior (probably an infantile behavior); some behaviors tend to pacify it (probably eliciting parental behavior) while others do not. The pacified state of B benefits A and reinforces its behavior, i.e. it is likely it will repeat the same behavior in similar circumstances. Most importantly, animals that show appropriate pacifying behavior (such as A) survive conflicts and avoid injury more often than not and subsequently pass their genes onto the next generation.

Pacifying behavior also pacifies the pacifier, which is an important feature of this behavior. By displaying pacifying behavior, an insecure animal attempts to regain some security (homeostasis) by displaying a behavior it knows well and has previously served to reassure it.

Dog and Cat

Cat and dog use the pacifying behavior of their own species to communicate with one another successfully because of the common characteristics of the behavior (photo by Malau).

Some pacifying behavior has its origins in neonatal and infantile behavior and only becomes pacifying behavior through redirection and eventually ritualization. Other forms of pacifying behavior rely on concealing all signs of aggressive behavior. Sexual behavior can also function as pacifying. Young animals of social species learn pacifying behavior at a very early age; it is important for young animals to be able to pacify adults when they begin interacting with them. The disposition (genotype) to display the behavior is innate (otherwise the phenotype would not be subject to natural selection and evolution), although it requires reinforcement for the young animal to be able to apply it successfully. In canines, adults (initially the mother at the time of weaning) teach the cubs/pups the intricacies of pacifying behavior, a skill they will need to master in order to prevent or resolve hostilities that could cause serious injuries.

Even though pacifying behavior is more relevant and developed in social species, we also find pacifying displays in the behavior repertoire of less social species. Animals successfully use the pacifying behavior characteristic of their species with individuals belonging to other species (if possible) because of the common elements of pacifying behavior across species. It is not unusual to see our domestic animals, dogs, cats and horses interacting peacefully and exchanging pacifying signals. Dogs also show friendly, insecure, pacifying or submissive behavior to their owners and other humans with their species characteristic displays. Licking, nose poking, muzzle nudging, pawing and twisting are common behaviors that dogs offer us.

This diagram shows the placement of pacifying behavior in the spectrum of behavior in canids. The diagram does not include a complete list of behaviors. A conflict is any serious disagreement, a dispute over a resource, which may lead to one or both parts showing aggressive behavior. Resources are what an organism perceives as life necessities, e.g. food, mating partner or a patch of territory. What an animal perceives to be its resources depends on both the species and the individual; it is the result of evolutionary processes and the history of the individual.

Pacifying Spectrum

The spectrum of pacifying behavior in canids (by R. Abrantes). The colored background illustrates and emphasizes that behavior is a continuum with fading thresholds between the various behaviors. The vertical lines are our artificial borders, a product of definition and convention.



  • Abrantes, R. 1997. The Evolution of Canine Social Behavior. Wakan Tanka Publishers.
  • Abrantes, R. 1997. Dog Language. Wakan Tanka Publishers.
  • Abrantes, R. 2014. Canine Muzzle Grasp Behavior—Advanced Dog Language.
  • Abrantes, R. 2014. Canine Muzzle Nudge, Muzzle Grasp And Regurgitation Behavior.
  • Abrantes, R. 2014. Why Do Dogs Like To Lick Our Faces?
  • Coppinger, R. and Coppinger, L. 2001. Dogs: a Startling New Understanding of Canine Origin, Behavior and Evolution. Scribner.
  • Darwin, C. 1872. The Expressions of the Emotions in Man and Animals. John Murray (the original edition).
  • Fox, M. 1972. Behaviour of Wolves, Dogs, and Related Canids. Harper and Row.
  • Lopez, Barry H. (1978). Of Wolves and Men. J. M. Dent and Sons Limited.
  • Mech, L. D. 1970. The wolf: the ecology and behavior of an endangered species. Doubleday Publishing Co., New York.
  • Mech, L. David (1981). The Wolf: The Ecology and Behaviour of an Endangered Species. University of Minnesota Press.
  • Mech, L. D. 1988. The arctic wolf: living with the pack. Voyageur Press, Stillwater, Minn.
  • Mech. L. D. and Boitani, L. 2003. Wolves: Behavior, Ecology, and Conservation. University of Chicago Press.
  • Scott, J. P. and Fuller, J. L. 1998. Genetics and the Social Behavior of the Dog. University of Chicago Press.
  • Zimen, E. 1975. Social dynamics of the wolf pack. In The wild canids: their systematics, behavioral ecology and evolution. Edited by M. W. Fox. Van Nostrand Reinhold Co., New York. pp. 336-368.
  • Zimen, E. 1982. A wolf pack sociogram. In Wolves of the world. Edited by F. H. Harrington, and P. C. Paquet. Noyes Publishers, Park Ridge, NJ.

Is it possible for all of us to become givers—no takers at all?

—by Roger Abrantes


Bird Mouse Alturism


Wouldn’t it be nice if we all gave without expecting anything in return? What a beautiful world we would have. At one time or another, most of us have embraced such thoughts. But is it possible at all? Is it possible for all of us to become givers—no takers at all?

An evolutionary biologist will tell you right away that it is not possible. Every behavioral strategy, when adopted by everyone in a group, is vulnerable to any variation or mutation that will carry a slight advantage. Were we all to become givers, we would be at the mercy of the first taker that would show up. More takers would follow for if it works for one, it works for others as well.

All relationships are a trade, a “give and take.” How much we give and how much we take depends on the benefits and costs involved. The goal is to come out of any trade with gain. Occasional deficits are acceptable as long as the overall balance stays on the plus side. That is the law of life. We spend energy to gain energy, to keep alive. Sometimes, we need to plan long-termed. There are both benefits and costs that we do not incur immediately. The law is still the same: the balance must end up on the positive side or life will end.

Apart from our dream of a better world full of unselfish givers, it looks at first sight like taking and not giving is the most profitable strategy. The problem is that we cannot all be takers. Takers can’t take from takers, they can only take from givers. Thus, it would appear that the givers would always be at a loss, but that is not the case. Givers receive from other givers, and they don’t spend energy fighting with takers. On the other side, takers spend energy when facing other takers without gaining anything. While giver/giver allows both to come out on the plus side of the balance, taker/taker always comes out with a deficit.

Givers and takers keep each other at bay. The ideal number for each, so that there is stability, depends solely on the value of benefits and costs.

To analyze how different strategies influence one another, the evolutionary biologist strips the strategies to their core and assigns some values to the variables, i.e. benefits and costs.

Let’s assume that when a taker meets a taker, they benefit nothing and spend much energy. When a giver meets another giver, they both give and take equally, and they spend some energy (they have both benefits and costs). When a taker meets a giver, the taker benefits 100%, and the giver spends energy (costs). We set the value of benefits and costs as follows:

  • benefit (b) 20 (conferred by the givers to anyone)
  • cost (c) -5 (the cost of giving)
  • taker/taker cost (e) -50 (this is the energy takers spend when fighting one another to take without giving).

Let’s now calculate the percentage of takers and givers necessary to achieve an equilibrium so that both strategies give the same profit.

The proportion of takers = t
The proportion of givers (g) = (1-t)
The average payoff for a giver (g) is G = ct + (b+c)(1-t)
The average payoff for a taker (t) is T = et + b(1-t)
There is an equilibrium (stability) when G=T.


Strategy Opponent’s strategy
Takers Givers
Takers e b
Givers c b+c


Example 1—With the above values for benefits and costs, 10% takers and 90% givers gives both a profit of 13 and there is stability. If the cost of takers fighting one another decreases, then it pays off (for more individuals) to become a taker.

Example 2—The figures in example 1 seem to suggest that takers should avoid one another as much as possible. Let’s say they do it in three out of four times. Then, and still with the same values, the number of takers can rise to 40%, and we still have an equilibrium, i.e. an ESS (Evolutionarily Stable Strategy). However, the profit will be less for both givers and takers, namely 7—more takers equals less profit for all.

That is a good example of what happens in our capitalistic human societies dominated by the idea of taking more and more. Takers take all they can but end up poorer than if they took less. The capitalistic instinct says, “take more,” but a more rational approach would clearly show that taking less would amount to profiting more. The strategy of taking maximally works only for a limited time. In the end, it backfires (depression, recession, etc.) because it upsets the balance between the available strategies, which, by then, have become evolutionarily unstable.

Example 3—Encounters between takers ar very expensive. What if takers would avoid takers all the time? In this case, the number of takers can rise up to 80%. Beyond that the strategies become evolutionarily unstable. The interesting is that even thought there would be stability with such a high number of takers, both takers and givers would come at a loss of -1. That is not at all a healthy strategy for any individual, let alone a group. It’s the sign of a society in decay. It’s what happens in a group, which is dominated by greed and selfishness.

Example 4—Since our wish is a world full of givers let us see how we can maximize the number of givers. We need to change the values for benefits and costs. Let’s decrease the cost of giving and increase the costs incurred by takers when fighting one another.

  • benefit (b) 20 (remains the same)
  • cost (c) -1 (lower cost than above)
  • taker/taker cost (e) -100 (much higher cost than above)

With these values, we can reach a maximum of 99% givers versus 1% takers. Both will have a profit equal to 18.80. Note that this the highest achieved profit in all our simulations.

The only variables that reduce the number of takers are the cost (e) and the probability of facing another taker. If we keep the values of benefits and costs the same as initially (b=20, c=-5) the costs of the struggle between two takers must rise to -500 for the strategies to be evolutionarily stable. The profit, then, would be 14.80 instead of 18.80.

These are artificial figures we use to analyze the necessary conditions for an Evolutionarily Stable Strategy to emerge. We may question the unlikeliness of the costs of an interaction to rise as high as we have set the taker/taker encounters. And yet, conflicts between male Northern elephant seals, Mirounga angustirostris, often end with a critical injury or the death of one of the parties. The costs are high, but so are the benefits: in Northern elephant seals, fewer than 5% of the males are responsible for 50% or more of the copulations. A red deer stag, Cervus elaphus, has about a 25% chance to be injured permanently from fighting (like in our example 2).

Also interesting is that the value of the benefits does not change the proportion of takers versus givers, only the profit. For example, with b=40, the profit is 34.60 (versus 18.80 and 14.80 for the other values for benefits in the examples). The values we used are all fictive, but it doesn’t matter. They show us the trends created by increasing or decreasing a variable. To evaluate real situations, we can use realistic figures inasmuch as we can get them. We can assign values to benefits and costs according to gain or loss of calories, body weight, number of progeny, available mating partners, fitness or even quality of life (if we find a reliable way to measure it).

The conclusion is that there will always be givers and takers—or that any strategy needs a counterpart to form an ESS. We can influence the trend of adopting one or the other strategy with the benefits and costs involved, but we can’t eliminate either one completely—and this is the universal law of life. In other words: every mountain has a sunny and a shady side.


The Mathematician Rat—An Evolutionary Explanation

— by Roger Abrantes


Giant Gambian Pouched By Xavier Rossi

Giant Gambian Pouched finds a landmine (photo by Xavier Rossi).

JG is a rat, a Cricetomys gambianus or Giant Gambian Pouched Rat; she is also a Hero Rat, a landmine detector at Apopo in Tanzania. In December 2009, she performed uncharacteristically badly and puzzled everybody as Hero Rats don’t make mistakes. What was the problem with JG? Had she lost it? Had the trainers made a crucial mistake?

Apopo in Morogoro, Tanzania, trains rats to detect landmines and tuberculosis and the little fellows are very good at what they do. In Mozambique, Apopo has so far cleared 2,063,701 square meters of Confirmed Hazardous Areas, with the destruction of 1866 landmines, 783 explosive remnants of war and 12,817 small arms and ammunitions. As for tuberculosis, up until now the rats have analyzed 97,859 samples, second-time screened 44,934 patients, correctly diagnosed 7,662 samples and discovered 2,299 additional cases that were previously missed by the DOTS centers (Direct Observation of Treatment, Short Course Centers in Tanzania). More than 2,500 patients have since been treated for tuberculosis after having been correctly diagnosed by the rats.

In December 2009, I was working full time at Apopo in Morogoro. I wrote their training manual, trained their rat trainers, supervised the training of the animals and analyzed standard operating procedures. At the time of writing, I still do consultancy work for Apopo and instruct new trainers from time to time. Back then, one of my jobs was to analyze and monitor the rats’ daily performance and that’s when I came across the peculiar and puzzling behavior of JG in the LC3 cage.


LC3 is a cage with 10 sniffing holes in a line and the rats run it 10 times. On average, 21 holes, randomly selected by computer, will contain TNT samples. We train rats in LC3 everyday, recording and statistically analyzing each session. We normally expect the rats to find and indicate the TNT samples with a success rate of 80-85%. Whenever the figures deviate from the expected results, we analyze them and try to pinpoint the problem.

On December 19, we came across a rat in LC3 that did not indicate any positive samples placed from Holes 1 to 6. She only indicated from Holes 7 to 10. In fact, from Hole 1 to 6, Jane Goodall (that’s the rat’s full name) only once bothered to make an indication (which was false, by the way). From Hole 7 to 10, JG indicated 10 times with 9 correct positives, only missing one, but also indicated 11 false positives. Her score was the lowest in LC3 that day and the lowest for any rat for a long time. What was the problem with JG? She seemed fine in all other aspects and seemed to know what she was doing. Why then did she perform so poorly?

Giant Gambian Pouched Rat By Silvain Piraux

Giant Gambian Pouched Rat searching TNT in a line cage (photo by Silvain Piraux).

Analysis of searching strategies

Whenever an animal shows such a behavior pattern, and it appears purposeful rather than emotional, I become suspicious and suspect that there is a rational explanation.

In order to analyze the problem, I constructed simulations of two searching strategies: (1) searching ALL HOLES, and (2) SKIPPING Holes 1 to 5 (I didn’t want to be as radical in my simulation as JG). In addition, I ran simulations with two different sample placement configurations: (1) evenly distributed between the two halves, i.e. two positives in Holes 1 to 5 and two positives in Holes 6 to 10; and (2) unevenly distributed — one positive in the first five holes and two positives in Holes 6 to 10.

In order to run the simulation, I needed to assign values to the different components of the rat’s behavior. I chose values based on averages measured with different rats.

  • Walking from feeding hole to first hole (back walk) = 3 seconds.
  • Walking from covered hole to covered hole = 1 second.
  • Walking from uncovered hole to uncovered hole = 2 seconds.
  • Analyzing a hole = 2 seconds.
  • Indicating a positive = 4 seconds.
  • Walking from last hole to feeding hole = 1 second.
  • Eating the treat = 4 seconds.

All time variables were converted into energy expenditure in the calculation of energy payoff for the two strategies and the different configurations. Also the distance covered was converted into energy expenditure. The reinforcers (treats) amounted to energy intake. In my simulation I used estimated values for both expenditure and intake. However, we could measure all values accurately and convert all energy figures into kJ. 

The results

In terms of energy,  (in this simulation I make several assumptions based on reasonable values, e.g. the total energy spent is a function of distance covered and time spent), the results show that when the value of each treat is high (E gain is close to the sum of all treats amounting to the sum of energy spent for searching all holes), it pays off to search all holes (the loss of -5.50 versus -7.88). The higher the energetic value of each treat, the higher the payoff of the ALL HOLES strategy.This is a configuration with four positives (x) and six negatives (0). The results show that neither strategy is significantly better than the other. On average, when sniffing all holes, the rat receives a treat every 31 seconds, while skipping the first five holes will produce a treat every 31.5 seconds. However, there is a notable difference in how quickly the rat gets to the treat depending on which strategy the rat adopts. ALL HOLES produces a treat on average 5.75 seconds after a positive indication. SKIPPING produces a treat 3.5 seconds after a positive indication. This could lead the rat to adopt the SKIPPING strategy, but it’s not an unequivocally convincing argument.


However, when the energetic value of each treat is low, skipping holes will reduce the total loss (damage control), making it a better strategy (-17.88 versus -25.50).

However, if we run a simulation based on an average of three positives per run, with one in the first half and two in the second half  (which is closest to what the rat JG was faced with on December 12), we obtain completely different results. This first analysis does not prove conclusively that the SKIPPING strategy is the best. On the contrary, it shows that, all things considered, ALL HOLES will confer more advantages.

The energy advantage is also detectable in this configuration, even when each treat has a high energetic value (a gain of 3.13 versus a loss of -0.75).With this configuration, the strategy of SKIPPING is undoubtedly the best. On average, it produces a reinforcer every 27.5 seconds (versus 28.7 for ALL HOLES) and 2.5 seconds after an indication (versus 5 seconds).


This second simulation proves that JG’s strategy was indeed the most profitable in principle. However, the actual results for JG are completely different from the ones shown above, as they also have to take into account the amount of energy spent indicating false positives (which are expensive).

It is now possible to conclude that the most advantageous strategy is as follows. Whenever the possibilities of producing a reinforcer are evenly distributed, search all holes. It takes more time, but on average you’ll get a reinforcer a bit quicker than if you skip holes. In addition, you either gain energy by searching all holes, or you limit your losses, depending on the energetic value of each reinforcer. Don’t be fooled by the fact you get a treat sooner after your indication when searching all holes then when skipping.

Whenever the possibilities of producing a reinforcer are not evenly distributed, with a bias towards the second half of the line, skip the first half. It doesn’t pay off to even bother searching the first half. By skipping it, you’ll get a lower total number of reinforcers, but you’ll get them quicker than searching all holes and, more importantly, you’ll end up gaining energy instead of losing it.

Finally, avoid making mistakes by indicating false positives. They cost as much as true positives in spent energy, but you don’t gain anything.          

An evolutionary explanation

Of course, no rat calculates energetic values and odds for certain behaviors that are reinforced, nor do they run simulations prior to entering a line cage. Rats do not do this in their natural environment either. They search for food using specific patterns of behavior, which have proven to be the most adequate throughout the history and evolution of the species. A certain behavior in certain conditions, depending on temperature, light, humidity, population density, as well as internal conditions such as blood sugar level etc., will produce a slightly better payoff than any other behavior. Behaviors with slightly better payoffs will tend to confer slight advantages in terms of survival and reproduction and they will accumulate and spread within a population; they will spread slowly, for the time factor is unimportant in the evolution of a trait. Eventually, we will come across a population of individuals with what seems an unrivalled ability to make the right decision in circumstances with an amazing number of variables, and it puzzles us because we forget the tremendous role of evolution by natural selection. Those individuals who took the ‘most wrong decisions’ or ‘slightly wrong’ decisions inevitably decreased their chances of survival and reproduction. Those who took ‘mostly right’ or ‘slightly righter’ decisions gained an advantage in the struggle for survival and reproduction and, by reproducing more often or more successfully, they passed their ‘mostly right’ or ‘slightly righter’ decisions genes to their offspring.

This is a process that the theory of behaviorism cannot explain, however useful it is for explaining practical learning in specific situations. In order to explain such seemingly uncharacteristic behaviors, we need to recur to the theory of evolution by natural selection. This behavior is not the result of trial and error with subsequent reinforcers or punishers. It is an innate ability to recognize parameters and behave in face of them. It is an ability that some individuals possess to recognize particular situations and particular elements within those situations, and correlate them with specific behavior. What these elements are, or what this ability exactly amounts to, we do not know; only that it has been perfected throughout centuries and millennia, and innumerable generations that accumulate ‘mostly right’ or ‘slightly righter’ decisions—and that is indeed evolution by means of natural selection.


Related articles


  • Catania, A. C. (1997) Learning. Upper Saddle River, NJ: Prentice-Hall. 4th ed.
  • Chance, P. (2008) Learning and Behavior. Wadsworth-Thomson Learning, Belmont, CA, 6th, ed.


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Why Do Dogs Eat Poop?—an Evolutionary Approach

Wolf Cubs At The Den

Canine mothers (wolf, African wild dogs and domestic dogs) eat their puppies poop when they are still in the den. The function of this behavior is to keep the den fairly clean, free of parasites, and probably also odor free.


Why do dogs eat their own poop? I’ll come back to this question, but allow me an introduction which I think might be relevant for your further studies of behavior. I believe that a little more knowledge about evolution and the processes that bring traits about, including behavior, would reduce drastically the number of erroneous explanations of the behavior of our pets. It would also spell the end of many old wives’ tales

I find on the Internet one horrendous explanation after the other, which the authors could avoid with a 101 course in Evolution. Even scarier is to read some rebuttals of perfectly scientifically valid accounts because of blatant ignorance.

That is why we offer our course ‘Evolution’ free of charge. Our students are doing very well. They have taken the test 753 times since Darwin’s birthday last year (February 12). Students try to take tests several times. We discovered that they took (and take) tests like they play computer games, which is perfectly all right. While playing, they learn. Therefore, the records show an alarming 55% of failed tests (412 tests) because many do attempt to take the test without reading the book. In the end, 86% have passed evolution. That is good (and this figure will be even better, closer to 100%) because those who failed are still attempting to pass—to win the game). 42 students (6%) have even scored 100% correct answers, which is brilliant (and difficult).

So, knowledge to everyone everywhere is working—and congratulations to our students. You are the brave ones creating a new world with the help of knowledge—not the sword.

The following questions are those that our students find more difficult. Here’s some help for you.

  • Natural selection acts on the _________.  Only 48% answer correctly. Yes, natural selection acts upon the phenotype, not the genotype. Recently, epigenetics have uncovered that the environment can act upon the way genes manifest themselves, but this is the exception, not the rule.
  • A _______ is a taxonomic level, one of the basic units of classifying living organisms. 56% answer species, which is correct. Most of the wrong answers are cell. A cell is a basic unit, but not at taxonomic level. I guess what tricks you here is the word taxonomic. Taxonomy (from Ancient Greekτάξις taxis, arrangement, and νομία nomia, method) is the description, identification, nomenclature, and classification of organisms. 
  • Natural selection is a random process. 57% answer no, which is correct. I think what confuses the others, who answer yes, is that mutations happen at random. However, whether these mutations confer an advantage or not, is not a random process. It’s still under the sharp scrutiny of the survival of the fittest algorithm. Natural selection is not a random process.
  • Artificial speciation (caused by human intervention) is just one particular case of speciation due to ____________ selection, not an exception. 46% answer natural selection, which is correct. In popular language, we call artificial in nature everything that is human made. However, humans are also part of nature and, therefore, their impact on other organisms is part of the same universal process—it is as natural as the influence of any predator on its prey.

I will give you now two examples of how a bit knowledge of evolutionary biology can help you analyze statements and avoid making claims that don’t make sense or are very unlikely to be true.

Why does my dog eat its own poop? That is a common question that I have been asked many times. Here are some popular answers.

Explanation 1: The dog knows that fewer predators will pay it any attention if there is no evidence of his having been around.

Is this probable? First, adult canines in nature are not particularly predated by any other species. They tend to defecate where that can, sometimes even using it to scent mark their territory, which is anything but concealing it. The only occasion where this occurs is when canine mothers eat their puppies’ feces while they are still in the den. The function of this behavior is to keep the den reasonably clean, free of parasites, and probably also odor free. Evolutionarily, those that didn’t do it suffered more cases of their progeny succumbing to disease. It might also have reduced the scent signature of the den helping it remaining concealed, but again that would only have been an advantage where predators with a reasonable sense of smell would share the same environment. It might have been beneficial for the Canis lupus lupus sharing their environment with bears (family Ursidae).

Conclusion: it is unlikely that dogs eat their poop to conceal their whereabouts from predators except for mothers consuming their puppies’ feces.

Explanation 2: He (the dog) knows that removing the evidence means no punishment for inappropriate elimination.

Is this probable? To be true, it requires that the dog associates the feces with the punishment. How probable is it that the dog associates its the act of defecation with the punishment from an owner arriving at the scene maybe 1-8 hours later? Natural selection has favored associations broadly spaced in time, but only for vital functions, like eating poisonous substances. There is evidence that the organism retains a kind of memory of anything that made it sick even occurring many hours later. However, we cannot envisage any situation in which it would be unconditionally and evolutionarily advantageous for an animal to associate defecating with a non-lethal punishment inflicted by some other animal. Natural selection would only favor it if the achieved benefits exceeded its costs grossly. It is true that insecure animals tend to keep a low profile, also restricting their urination and defecation to less-prominent locations, but not by eating it.

Conclusion: it is definitely possible to condition an association between feces and punishment, but I doubt we can teach any dog to eat its feces to avoid punishment. There is no evidence that eating own poop has been evolutionarily advantageous.

When analyzing a behavior, the evolutionary biologist asks: (1) what condition in the environment would favor the development of such a trait, (2) what conditions would favor its propagation into the population, (3) do the benefits of such a trait outweigh its costs both short and long term?

Why do dogs eat their own poop, then? I don’t know. You may need to ask a vet, and now you are in a better situation than earlier to evaluate any answer you may get because you know how to analyze an argument from an evolutionary point of view.

Enjoy your studies.



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The Evolution of Life in 60 Seconds


Today, I have this little movie for you showing the evolution of life in 60 seconds. It puts it all into perspective, doesn’t it?

I’m still fascinated by this amazing logarithm “the survival of the fittest.” As Daniel Dennett writes, “I say if I could give a prize to the single best idea anybody ever had, I’d give it to Darwin—ahead of Newton, ahead of Einstein, ahead of everybody else. Why?  Because Darwin’s idea put together the two biggest worlds, the world of mechanism and material, and physical causes on the one hand (the lifeless world of matter) and the world of meaning, and purpose, and goals.”


Mount Rinjani, Indonesia.

Simulations of the volcano hypothesis were able to create organic molecules. Life could have originated in a ‘warm little pond’ in similar ways. (From “Evolution” by Roger Abrantes. Picture: Mount Rinjani, Indonesia by Oliver Spalt.)


Let me quote from my own little book “Evolution“:

“When we say that natural selection favors the fittest, we do not mean the one and only champion, but the fitter (or best-fitted) in the population. How fit they will have to be, depends on the environmental circumstances. In times of food abundance, more individuals will be fit enough to survive and play another round. In times of famine and scarce resources, maybe only the champions will have a chance. In any case, the algorithm ‘the fittest’ is always at work.

Most objections to the theory of evolution by natural selection fail to realize the function of time. Given enough time, whenever there is variation, natural selection will come up with all imaginable forms of life, always the fittest for the given environment and period.”

It’s all so simple. For example, I know beyond any reasonable doubt that you, my friends reading these lines right now, have all had fit ancestors. How do I know that? I’ll leave that one for you to figure out.

Keep smiling!



We want to protect them, who need it most, our children and our animals. We want to keep offering "Knowledge to everyone... everywhere," free courses and blogs. Join us, buy "Dogs And Children," book and course, for the cost of a cup of coffee and a muffin. Help us to help them.