In evolutionary footing , the domesticated chicken is one of the most successful species on Earth . There are an estimated 20 billion chickens active right now — almost three times as many as there are man . Apparently , “ try good to mass so they ’ll protect you ” is a middling efficacious evolutionary strategy — aside from that whole “ they consume you ” thing . Statistically , every man on the major planet eats the equivalent of 27 individual chickens every yr . The only other planetary vertebrate that might rival the chicken in sheer numbers is the Norway rat .
More than just a intellectual nourishment germ , though , the humble chicken has taught us some authoritative lessons . Through the thrifty notice of a backyard chicken flock , one of the most crucial rule of social biology was uncovered — one that applies as well to man .
Norwegian Knowhow
In 1904 , 10 - year old Thorleif Schjelderup - Ebbe was target in bang of caring for his family ’s flock of chickens in Kristiania , Norway ( which is now the city of Oslo ) . Schjelderup - Ebbe had a keen interest in nature and animals , and as he began to cautiously watch out the behavior of the chicken , he wrote down detailed descriptions and reflection in a daily diary .
For more than 4,000 years , since the ruddy jungle - fowl was first naturalise in Southern Asia , husbandman had acknowledge that a deal of hens was a very neat mathematical group . At eating time , the prevailing birds in the flock would eat first , pick out the best morsels . Then , the more submissive birds got their chance , and finally , the least prevailing got whatever was left . Farmers knew that if anything pass off to disrupt this order — introducing a raw bird to the heap or removing one of the prevalent birds — there would be a brief period of discord as birds fight back with each other to re - establish ascendence . Then , peace would reign once again .
But it was n’t until young Schjelderup - Ebbe began his age of observations , however , that anyone finally begin to get a readable picture of how this pile purchase order was established and maintained . Through years of put down information , he realize that there was a hierarchy within the heap .
The dominant hen at the top get first selection at all the nutrient and the best roosting spot , and if any other dame tried to infringe on those prerogatives , she would speedily peck the usurper into meekness . And this was not base entirely on size : The older , savier hens were often able-bodied to dominate even big , naive razz . The second - ranking bird , on the other hand , was able to hen-peck any subordinate word but dared not endeavor to verify herself against the predominant raspberry . And so it went down the line , with each hen pecking the birds ranked below her and in go being pecked by those above her .
When Schjelderup - Ebbe became a zoological science scholarly person at the University of Oslo and write his Ph.D. dissertation in 1921 on the social anatomical structure of Bronx cheer , he called this the pecking order of magnitude . The concept of the say-so power structure and pecking order was quickly put on to societal animal groups roll from Pisces to wolf to humans .
Picking The Order
For the most part , the result social fiat is peaceful : Each chicken knows her spot and stay in it . It ’s a rare matter to see undefendable armed combat over control in any well - established tidy sum , unless there is some sort of dislocation . Though the pecking order itself can occasionally change if old birds develop too weak to defend their position or untested razzing become more experienced and move up in rank and file .
Schjelderup - Ebbe was capable to see enough lesson of fighting to notice the pattern that lay beneath them but only after several years . afterwards experiments by other researchers established that the chickens in a flock need not even engage in factual scrap to find out who was prevailing to whom ; the fowl were able-bodied to learn their own place by see the results of fights with others .
If Chicken No . 2 dumbfound Chicken No . 3 in a fight , for example , Chicken No . 4 will learn that she ca n’t mess with Chicken No . 2 , even if they have never fought . In fact , investigator recover that Chicken No . 4 will be subservient to Chicken No . 2 even if they had never understand each other before and stay so even if they are then separated for months or years and reintroduced .
Far from being the dumb - as - a - sway chicken brain of popular image , barnyard chickens were capable of understanding and retaining an tremendous amount of information about their societal surroundings . But Schjelderup - Ebbe realized that the pecking rescript was not a simple linear run , which fall neatly into a rigid set of rungs . Many times , he had observe instances where Chicken No . 1 would dominate Chicken No . 2 , Chicken No . 2 would peck Chicken No . 3 , but Chicken No . 3 was often able-bodied to assert herself against Chicken No.1 . Schjelderup - Ebbe called these situation “ triangles . ”
Numbers Game
Another discovery made by Schjelderup - Ebbe in his parents ’ chicken coop , however , also had unexpected relevance to human evolution . He find out that if the size of the flock grew above 30 birds or so , the chickens were unable to think of all the societal relationship , and their pecking order completely broke down . Now , rather of the orderly peaceful social grouping they had been living under , no bird hump its position , and every bird tended to occasionally seek to assert dominance over another , at random .
Over the centuries , chickens have been bred for size , egg production and meatiness , but they have not been selectively bred for disposition . In the absence of a societal hierarchy to keep them in balk , chickens are naturally aggressive and quarrelsome birds ; after all , they were originally used by humans for cockfighting , not as food animals . In very large slew , then — such as the thousands of birds in a typical fowl mill farm — bird - on - doll violence is perpetual and never - ending .
To add to the problem , chickens are course triggered by bright - red colors , which is why roosters have hopeful - red combs at breeding time . Once a biddy in a flock pecks another hen and pull rakehell , the wound then attracts the sleep of the sight who pick up at it also , unremarkably stimulate disastrous harm .
Some farm attempt to stop this by keeping the birds under changeless cherry-red light bulbs , which micturate red look duller and lessens the spark off aggressiveness . But by far the most vulgar method of preventing trauma and dying in the large commercial flock is to de - pick all of the chicken , by cutting off the needlelike destruction of their beaks with an electrically heated trimmer so they ca n’t pick each other — barbaric at best .
From Poultry To People
In 2003 , British evolutionary psychologist Robin Dunbar randomly pick out a routine of English phratry and made a simple measure : How many Christmas cards did they send out every year to friends , home and acquaintances ? What Dunbar found was exactly what he had already expected to regain : Nearly all of his test subjects , no matter where they experience or what their profession or level of education or income , sent out rough 150 Christmas card .
How had Dunbar made that prediction ? After mathematical sociologist H.G. Landau ’s studies on chicken societies ( see “ The King Chicken Theorem ” on page 55 ) , biologists had also began studying high priest beau monde . One of the chair figures in this effort was paleo - anthropologist Louis Leaky , who dispatched three of his students to study ape in the wild , hope it would supply insight into how early hominid societies serve . It was soon discovered that there seemed to be a mathematical relationship between the size of a primate brainiac ’s lens cortex — the part of the brain that manage witting thought , retentiveness and learning — and the number of single members in that specie ’ distinctive band . The boastful the Einstein was , the grown the troop size of it was .
In 1992 , Dunbar applied this mathematical relationship to humans , and he found that a typical human troop should bear about 150 individuals . This became known as Dunbar ’s routine , and it relates directly to the chickens . ( See “ Dunbar ’s turn ” on pageboy 57 for examples . )
Just as the chicken brain can only remember and process about 30 different societal relationships , the human brain can only manage about 150 . Like the chickens , if you exceed the jumpy maximum bit of social relationships that the human brain can handle at once , the whole system collapses . While you might hold up in a city of 15 million people or have a million friends on the net , you ca n’t really bed more than 150 of them ; everyone after that is just a name , no different than a alien .
In prelate groups , bigger turn mean better protection , as the larger group is more good at notice and fighting off predator and fight the radical ’s territory from penetration by neighboring groups . But more social members also means more social relationships to keep track of , and as primate society became more complex — unlike chicken , primates are able-bodied to form social alliances and friendly relationship that allow them much more power and flexibleness inside the dominance hierarchy — the number of potential social permutations grows exponentially .
The human translation of The King Chicken Theorem is enormously complex . The event was a ratcheting effect during hominid evolution : Bigger and more complex societal groups lead to with child and near brains to sue all that new social selective information , which in turn reserve larger social group to form .
Our bounteous brains , which countenance us to ponder the universe , evolved so we could keep track of who we could nibble on in the societal pecking parliamentary procedure , and who could pick on us . In the end , wimp politics and human politics are n’t that much different from each other .
