– Cowanchee
What makes the human brain so special? Yes, of course, it is large - but by no means the largest of the existing ones. Of course, you have heard that your brain consists of one hundred billion neurons - but where did this figure come from and how does it look against the background of indicators of other living beings?
You may think you know the answers to these questions, but there is a good chance you have been seriously misinformed as to why your brain is more specific than the brains of other living beings on our planet. Here are four of the biggest myths about the human brain.
Myth 1: There are 100 billion neurons in the human brain.
Neurons are the fundamental building blocks of any nervous system. These specific cells, whose arborescent processes diverge in all directions and come into contact with the same processes of neighboring cells, form a huge electrical and chemical network, which is our brain, and process information about our environment, control our actions in accordance with this very environment, and even control our unconscious bodily functions. It is our neurons that allow our brain to perform various actions faster and more efficiently than any machine ever created.
Given the indispensable role these cells play, you might assume that scientists have a couple of ideas about exactly how many neurons we have between our ears; and for years we thought it was. Flip through a few neuroscience textbooks, a couple of scientific studies, and scientific journals, and you'll find that many people put the number of neurons in the human brain in a nice round number of one hundred billion - and usually do this without supporting references.
Why no links? According to neuroscientist Dr. Herculano-Hauzel, this is because no direct estimates of the total number of neurons in the human brain were made until 2009, when she and her team removed the brains of four recently deceased people, brought them to the lab, and liquefied them using the technique called "isotropic fractionalization". Herculano-Hauzel and her team dissolved each brain into a homogeneous "brain soup" emulsion (her words, not ours), took samples from the soup, counted the number of neurons in each sample, and then extrapolated to get the total number of neurons in every brain "cake".
We found that the average human brain contains approximately 86 billion neurons,” says Herculano-Hauzel in a recent Nature podcast. She then continues: No brain that we have studied so far has a hundred billion cells. And while it doesn't seem like much of a difference, 14 billion neurons is the size of a baboon's brain, or almost half the neurons in a gorilla's brain. So it's actually quite a decent difference.
Myth 2: The bigger the brain, the better it is.
If you manage to gather together a pack of several closely related species of living creatures, open their skulls and scrape out their brains, you will most likely begin to notice correlations between the absolute size of the brain and the cognitive abilities of the animal. Among mammals, for example, primates (like us) and cetaceans (like dolphins) have larger brains than, say, insectivores (like anteaters), and possess what most might recognize as proportionally greater mental abilities. Based on this observation alone, you might be inclined to think that brain size is a good predictor of cognitive performance.
However, the “bigger is better” relationship breaks down as soon as you start comparing individuals of different species. Cows, for example, have larger brains than just about any kind of ape, but unless they're very (very) good at hiding it, cows almost certainly have less intelligence than most (if not all) "less brainy" primates. Similarly, the brain of a capybara may weigh over seventy grams, but its cognitive abilities pale in comparison to those of the capuchin monkey, whose brain weighs only fifty grams.
Of course, for the purposes of our discussion on human brains, the most telling evidence that "bigger is not better" will be a comparison of the size of our brains and the brains of the largest mammals, such as a whale or an elephant. In the picture you can see a comparison of the human brain with the much larger elephant brain. The average human brain weighs about 1200 grams, and the elephant brain is almost four times as much, but the largest brain is that of the sperm whale, and it weighs 6800 grams.
With a brain that weighs six times the size of a human, why haven't sperm whales subjugated humanity yet?
Myth 3: The human brain is the largest in relation to body size.
This myth comes to us from the time of Aristotle, who in 335 BC wrote: "Of all animals, man has the largest brain in relation to the size of his body." This trap is easy to fall into if you try to explain the difference between brain size and intelligence in, say, humans and sperm whales. These days, many people use roughly the same explanation as Aristotle to convince themselves that the relationship between brain size and intelligence is not absolute weight or brain size, but rather the ratio of brain weight to body weight.
Study this logical chain closely, and you will find that it gives us another inaccurate picture compared to what we actually observe in nature. Yes, the human brain-to-body ratio is huge compared to, say, an elephant (about 1/40 versus 1/560, respectively); but it is about the same ratio as a normal mouse (also 1/40), and even less than the ratio you can find in some small birds (1/12).
To overcome the limitations of the basic brain-to-body ratio, the scientists came up with a more sophisticated scoring system known as the "encephalization factor" (EQ), which measures an animal's brain-to-body-size ratio compared to other animals of roughly similar size. In this case, EQ not only takes into account the fact that brain size tends to increase with body size, but also that brain size does not necessarily change. proportionately body enlargement.
When scientists compared encephalization factors in different animals, they found that this factor is higher in humans than in any other living creature on our planet.
Myth 4: A larger brain contains more neurons than a small brain.
But even the encephalization factor has an inherent flaw, for one simple reason: a larger brain does not necessarily contain more neurons than a smaller one—a fact that brings us back to myth number one and the question of how many neurons the human brain actually has.
Scientists, of course, have known for a long time that the size of an animal's brain can vary greatly between species. But until very recently, however, most studies assumed that the density of neurons constant value among different classes of animals. However, this belief cannot be further from reality.
Click to enlarge This myth was deftly debunked by Dr. Herculano-Hauzel and her team when they used the same brain soup method used to measure the number of neurons in the human brain to determine the total number of neurons in different mammalian species. The results of their research, which have already been published in a series of reports, demonstrate that the brains of different mammals follow different "rules of calculation":
primate brains, were found to increase in size at the same rate as the number of neurons in them grows; if you compare one gram of neuronal tissue from a large primate with one gram of tissue from a smaller primate, you will get roughly the same number of neurons.
rodent brains, on the other hand, as it turned out, increase in size faster, than acquire new neurons. As a result, larger rodents tend to have fewer neurons per gram of neuronal tissue than smaller species.
brains of insectivores behave like a combination of rodent and primate brains, with a cortex that grows in size faster than the number of neurons (like rodents) and a cerebellum that has a linear ratio of growth rates (like primates).
The bottom line is that among rodents, insectivores, and primates, the primate brain is built on the most economical, space-efficient principle. Dr. Herculano-Hauzel writes: A tenfold increase in the number of neurons in a rodent brain means a 35-fold increase in the brain itself; by comparison, the same tenfold increase in the number of neurons in the primate brain means an increase in brain size of only eleven times.
The brain of a hypothetical rodent with 86 billion neurons (similar to the human brain) would have to weigh a monstrous thirty-five kilograms - which is many times greater than all known parameters for any of the living creatures.
Is the human brain special?
There are several conclusions that can be drawn from the debunking of myth number four.
Firstly, it demonstrates that the relative size of the brain (even with the influence of the encephalization factor) cannot be used as a reliable measure of the number of neurons in different classes of animals. Moreover, it actually leads us to the conclusion that brain size, body size, and the relationship between them are not sufficient indicators of cognitive ability, and that such assumptions should rather focus on the total number of neurons that a given creature has.
And secondly, this reveals two rather counterintuitive facts about the human brain. The first is that our brains are, to some extent, not unique at all. It may contain 86 billion neurons, but that's exactly the number you'd expect to find (based on the primate calculation rules) in a brain of this size; if you enlarge the brain of a chimpanzee to the size of a human brain, you will find exactly the same number of neurons in it.
And the second is to confirm the fact that some things in the human brain are indeed unique.
Dr. Herculano-Hauzel explains:
First, the human brain grows according to the same rules as the brain of primates: a more economical principle compared to rodents allows you to pack into the available volume many more neurons than in the brain of a rodent of the same size, and possibly in the brain of any other living creature of that size. the same size. And secondly, our position among primates as the owners of the largest functioning brain ensures that, at least among primates, we possess the largest number of neurons that contribute to the formation of consciousness and behavior in general.
How our unprecedented number of neurons in the brain combines with things like our genetics and overall brain structure that results in the most advanced cognitive abilities on our planet remains to be found.
For example, if the brain of a chimpanzee could somehow be enlarged to the size of a human, would we see a jump in his cognitive abilities to a level corresponding to ours?
Another "as yet unexplored" question is how to compare our number of neurons and "rules of calculation" with other mammalian species, and especially those with larger brains? To date, there are no studies on the exact number of neurons in either elephants or cetaceans.
Scientists study and determine the ratio of the volume of the brain to the volume of the bodies of living beings on Earth. They also found out which of the animals has the heaviest brain. It is known that among people there are record holders for the weight of the brain.
Who has the largest brain relative to body?
Comparing the ratio of brain mass to body mass, it turned out that among vertebrates, the hummingbird occupies the first place. This bird has a ratio of 1/12. It would be possible to determine the ratio among invertebrates, however, as such, they do not have a brain, but there are nerve nodes or ganglia. If you calculate the ratio by comparing the mass of nerve endings with the body mass of invertebrates, it turns out that the ant is the champion. Its ratio is 1/4.If a person had a ratio of 1/4, like an ant, the head would weigh at least twenty kilograms, and would be about eight times larger. However, an ant brain is forty thousand times smaller than a human brain when compared to the number of cells it is made up of.
Scientists conducted research and experiments to understand whether the ant has a mind. It turned out that these miniature insects are able to generalize and synthesize the information they receive.
Ants can learn, they mature gradually, which confirms their complex social appearance. And the more complex the species, the more time the ant spends on learning. It is the nervous system that prevents ants from being considered intelligent animals. Due to the fact that the brain of this insect consists of five hundred thousand neurons, it is not capable of thinking. A number of scientists believe that among ants there is a distribution of the brain among the members of the colony. This distribution is comparable to the connection of computers via the Internet to solve certain problems.
It turns out that each ant is a small particle of a huge super brain. This is a riddle for scientists that they are trying to solve. There is a version that they act in concert thanks to radio waves or telepathy.
Such a coincidence is surprising - a similar ratio in humans is the same as in Mormirus fish or elephant fish. It is equal to 1\38-1\50. Among fish, it is the Mormirus fish that has the largest ratio of brain mass to its body mass.
After examining the ratio of interest among primates, it was found that the largest ratio is not in humans at all, but in the Squirrel Monkey or Saimiri. This ratio in this primate is 1/17.
Animals with big brains
Researchers, after observing dozens of different types of animals, concluded that those whose absolute brain volume is larger have better control over their behavior. This is not about the mass of the brain, but about its ratio with the volume of the body. Interestingly, monkeys, wolves, carnivorous dogs showed good self-control, but the elephant showed poor results.You can evaluate the brain not by the ratio of its volume to the volume of the body, but by size. Several record holders. It is known that among terrestrial animals the brain of the largest mass is in the elephant. About five kilograms - the brain of an Indian elephant weighs so much.
The record holder among all living creatures of the planet in terms of brain weight is the whale Physeter Macrocephalus. The brain of this animal can reach nine kilograms. However, if you calculate the ratio of brain to body, you get 1/40,000. The weight of a whale's brain depends on its age and species. It is known that the blue whale is much larger than the sperm whale, but its brain is smaller and weighs only six kilograms eight hundred grams.
Another owner of a large brain is the northern beluga dolphin. Its brain weighs two kilograms, three hundred and fifty grams, while that of the bottlenose dolphin weighs only one kilogram, seven hundred and thirty-five grams.
The living being of the planet with a big brain is man. On average, his brain weighs from one kilogram twenty grams to one kilogram nine hundred and seventy grams.
The largest human brain
The weight of the human brain depends on many factors. Firstly, the male brain is larger than the female by about one hundred to one hundred and fifty grams. There is no significant difference in brain weight between individual races. 
Our ancestors had much smaller brains than ours. Weight changed significantly when the first primitive man appeared. The brain of Pithecanthropus did not exceed nine hundred cubic centimeters, and the brain of Sinanthropus was about one thousand two hundred and twenty-five cubic centimeters, thus catching up with the brain of a modern woman. It is known that the Cro-Magnons had a brain, the volume of which is one thousand eight hundred and eighty cubic centimeters.
Today, the brain of a European is about one thousand four hundred and forty-six cubic centimeters. It can be concluded that every two hundred years the brain "shrinks" by one cubic centimeter. I would like to hope that the decrease in volume does not lead to a drop in intelligence, but is caused by an improvement in the design.
It is known that Ivan Sergeevich Turgenev's brain weight turned out to be equal to two kilograms and twelve grams. One could consider his brain to be the largest, however, in a certain individual who lived only three years, the weight of the brain was two kilograms nine hundred grams.
Some celebrities just need to keep their brains busy. According to the site, Christina Aguilera does not know where the Cannes Film Festival is taking place. .
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The elephant's brain is the largest brain among all land mammals that live on our planet. It is located at the back of the head and occupies a small part of the volume of the skull. Consider the main characteristics and features of the brain of these animals, and also compare it with the human brain.
Elephant species
Currently, three species of these animals live on our planet:
- African elephants. They live in most of Africa and are the largest species of terrestrial animals. Large specimens of these animals reach 7.5 meters in length, 3.3 meters in height and weigh up to 6 tons. The tusks of this species of elephants grow throughout their lives, both in males and females. The African elephant has large ears to give off more heat into the atmosphere. This species is endangered due to poaching.
- Indian elephants. This type of elephant lives mainly in India. Its specimens grow up to 6.4 m in length and up to 2-3.5 m in height. The elephant is dark grey. It occupies an important place in Indian culture.
- Asian elephants. These elephants are the largest. They reach 6.4 m in length and 3 m in height. The weight of an adult individual is within 5 tons. Unlike the African elephant, they have small ears that are constantly moving to cool the animal's head. Most males do not have tusks.
Some facts about the brain of elephants
Here are important facts that characterize the brain of the largest land animals on the planet:
- the brain of newly born elephant cubs is 35% by mass of the mass of the brain of an adult animal;
- elephants are among the smartest animals on earth;
- the brain of an African male has a mass of 4.2 to 5.4 kilograms, while the mass of the brain of an African female is 3.6-4.3 kilograms;
- Elephant brain development is similar to that of humans.
The Importance of Brain Size
Although the elephant's brain is the largest mammal on Earth, it only occupies a small area at the back of the animal's head. If we take the ratio of brain weight to body weight, it turns out that this figure for elephants will be less than for humans. Be that as it may, the elephant is the only animal, along with primates and sperm whales, that has a fairly high ratio of brain size to body size.
The size of the brain is important because it correlates with the flexibility of the animal's thinking, or, as it is commonly said, with its intelligence, and also determines the complex social structures and relationships in the population of these animals.
How much does the brain weigh in males and females?
In both African and Indian elephants, the size of the brain depends on whether the individual is male or female. The weight of the brain of the males of the African elephant is more than the weight of the females of this species, by 0.6-1.1 kg, and is 4.2-5.4 kg. It is important to note that this difference in the brain weight of the animals does not affect their mental abilities.
Many studies of the behavior of elephants have demonstrated quite reasonable behavior of females, which were in no way inferior to male elephants. This is explained by the fact that it is not the weight of the brain itself that is important for reasonable behavior, but the ratio of its mass to body weight. Since female elephants are usually smaller than males, the difference in this ratio is practically zero. In addition, the consciousness itself in females is very different from that of males, since they are attached to their mothers and, starting from early childhood, form stable bonds with other females of their herd, which they maintain throughout their lives. Males are more solitary nomads.
brain development
It is interesting to note that the brain of elephants develops similarly to the brain of primates, including humans. Elephant and man are born with a small brain mass: in an elephant it is 35% of the brain mass of an adult, and in humans - 26%.
These numbers suggest that there is room for significant brain development in animals as they grow. As the mass of the brain increases, various abilities, including mental ones, actively develop in young elephants. Conducted studies on the behavior of elephants, as well as the anatomy of their brain, suggest that elephants are very intelligent animals.
Elephants are smart animals
Thanks to a developed brain, elephants remember the location of oases with water during a drought period, and are able to recognize the bones of their dead relatives. They may even love. Elephants are able to identify whether a given person is dangerous to them or not, because animals distinguish between people of different ethnic groups, distinguish between human languages, age and gender. Dolphins and whales have similar abilities. It has been observed that young elephants learn from their older counterparts throughout their lives.
For example, one of the populations of African elephants lives near the territory where the Maasai tribes live. Elephants are afraid of the people of this tribe, because conflicts often break out between animals and the Maasai due to the lack of vital resources, which is a common problem in Africa. Animals have learned to recognize the smell and red color of the clothes of the people of the tribe.
Scottish scientists from the University of St. Andrews found that the developed brain of elephants allows them to understand many human gestures without prior training. This fantastic discovery puts elephants at the top of the list of animals that can understand humans in sign language. Thanks to this ability of animals, they were able to domesticate and establish a strong friendly relationship between the elephant and its owner, despite the danger of the elephant and its large size.
Comparison of the brain of an elephant and a human
If mental capabilities depended only on the mass of the brain, then knowing how much a person’s brain weighs (approximately 1.4 kg), one could say that he is much more stupid than an elephant, since the brain of an animal weighs 3-3.5 times more.
It is also impossible to identify mental capabilities with the ratio of brain and body masses. For example, for a human this figure is 1/40, and for an elephant it is 1/560, but for small birds the ratio is 1/12.
The difference in mental capabilities is not associated with the mass or volume of the brain of an elephant and a person, but with structural features. Most scientists are inclined to believe that the mental abilities of a person are associated with the complex structure of his cerebral cortex, which includes 16 billion neurons, and in this indicator significantly exceeds the brain of any animal, including an elephant, which has less 3 times neurons than in humans. Each human neuron is capable of forming tens of thousands of connections with others. In addition, all brain neurons are packed into several layers, which leads to an increase in their density, in comparison with the brain of an elephant.
As for the elephant, it should be noted that the structure of its cerebral cortex is different from that of primates. In particular, it contains a greater number of cell types, which, according to scientists, plays an important role in the manifestation of the mental abilities of these animals.
“Let the horse think, it has a bigger head!” - familiar phrase?
And everything seems to be logical - the larger the brain, the smarter its happy owner. Yes, and there are a lot of examples of this: all sorts of insects-cockroaches with a brain of a few milligrams, mice, squirrels and titmouse with a brain weighing only about 1 gram, and then - cats (about 30 gr.), Dogs (about 100 gr.) And anthropoid monkeys with brain weighing about 400 gr. - Well, they can’t compete with such clever people like you and me, who have, on average, 1400 grams of gray matter. So far everything seems to be correct.
Well, then complete misunderstandings begin: missing out on all kinds of horses and cows with a brain weight of 300-400 grams, an elephant has a brain weight of more than 5 kg, and sperm whales, in general, more than 7 kg! Wow! So that's who they are - the smartest and wisest! An-no!
It turns out that intelligence just depends not so much on the size and weight of the brain, but on the ratio of its weight to the total weight of the whole body. And here man has no equal!
Well, for example: In humans, the ratio of body weight to brain weight is: .... So…. 70 kg divided by 1.4 kg…so…. Yep, 50 times. But in a cow - 1000 times, in a dog - 500 times, in a chimpanzee - 120 times. Well, if you count whales and sperm whales among the "wise men", then in general it turns out that the weight of their body exceeds the weight of the brain by as much as 3000 times!
In general, our only and closest “intelligence” relatives are dolphins, the brain weight of some species of which reaches 1700 grams, with a body weight of about 135 kg.
But I wonder if there is a difference in the weight of the brain, so to speak, within the human race? It turns out yes, there is!
We continue.
In general, our brain is a rather energy-intensive and energy-consuming thing. For example, a "resting" brain consumes 9% of the body's energy and 20% of oxygen, and a "working", that is, a thinking brain, consumes about 25% of all nutrients entering the body and about 33% of the oxygen that the body needs so much. In general, it turns out that thinking is not very profitable! And even, the question arises: why do we need such a large and “gluttonous” brain?
It turns out that, in addition to saving energy, one more factor is very important for survival, both in the animal world and in the human world - reaction time. And this is where our big brain comes in very handy! A person uses it as a matter of fact as a large and powerful computer, which turns on when it is necessary to dramatically speed up the solution of complex tasks that require enormous stress and quick response. That is why, although our brain is insanely voracious, it is sooo necessary and irreplaceable.
So how does this "computer" work?
The human brain weighs from 1100 to 2000 grams, which is about 2% of the total body weight. At the same time, the mass of the female and male brain is different - in the strong half, the brain is “heavier” by about 100-150 grams. According to scientists, the weight of the brain also depends on the age of the person. For example, a newborn baby has a brain mass of 455 grams. So how much does the human brain weigh? Let's try to understand this interesting question.
How much does an adult human brain weigh?
The brain is made up of many nerve cells and is one of the most important organs in the body. There is an opinion that the level of a person's intelligence depends on the mass of his brain. However, this is nothing more than a myth - the brain of a genius may well turn out to be smaller than the brain of a person of low mental abilities. It is enough to trace the "dimensions" of the brain of many great minds of mankind. So, let's turn to statistics and compare the brain mass of such prominent personalities as:
- Walt Whitman - 1256
- Lenin - 1340
- Stanislavsky - 1505
- Trotsky - 1568
- Mendeleev - 1571
- Pavlov - 1653
- Beethoven - 1750
- Yesenin - 1920
- Turgenev - 2012
- Byron - 2238
As you can see, the presence of talent or personal gifts does not depend on the weight of the human brain. It has been proven that the level of intelligence is affected by certain parts of the brain - the "gray matter". And here, in turn, the density of the location of neurons and the number of connections between them play a decisive role.
Many diseases may well provoke an increase in the cerebral cortex, which will affect its mass. Science has recorded the largest brain - weighing 2850 grams! True, the owner of such a "unique" was a weak-minded person.
An interesting fact: representatives of different races and nationalities have different brain masses. For example, Belarusians have an average brain weight of 1429 grams, while Russians have 1399 grams. If we compare the brain mass of a black American (1223 grams) and the "average" German (1425 grams), then the difference between the indicators will be 202 grams.
The human brain weighs between 1100 and 2000 grams.
Australians have the "lightest" brain - 1185 grams! A little “heavier” is the brain of Asians - Koreans and Japanese (1376 grams and 1313 grams, respectively).
It should be noted that the weight of the brain is not a static value. From birth to age 27, the brain “grows” in weight, and then its mass gradually but steadily decreases. For every next 10 years, a person “loses” 30 grams of the brain!
How much does an elephant's brain weigh?
The average mass of the brain of an elephant is from 4000 to 5000 grams. Compared to the weight of the human brain, the largest mammalian brains are more than twice as heavy. As it has been scientifically proven, the level of intelligence does not depend on the size of the brain - otherwise, the “crown of creation” on the planet would not be a person, but elephants and whales.
The mass of the brain of an elephant is from 4000 to 5000 grams.
What criterion affects the potential level of intelligence? This is the ratio of brain mass to total body weight. Observation of different types of animals showed that animals with a higher score are able to control their behavior better. In humans, the ratio of brain weight to body weight is 1: 40, but elephants cannot “boast” of such successes - in these huge mammals, this figure is 1: 560.
How much does a whale's brain weigh?
The mass of the brain of a whale reaches 9000 grams.
The blue whale is the largest mammal that has ever lived on Earth. Indeed, the body length of a whale often exceeds 30 meters, and its weight is more than 150 tons.
The brain mass of this water "record holder" reaches 9000 grams, and the ratio of this indicator to the total body weight is 1: 40,000.
How much does the brain and heart of a blue (blue) whale weigh?
An interesting fact is that the weight of a whale's heart is between 600 and 700 kg, and the brain weighs an average of 6.8 kg. As you can see, the whale brain is about 100 times lighter than the heart. Why does a whale need such a “big” heart? The fact is that a small heart would hardly have coped with transporting blood through the vessels of such a huge multi-ton body.
The northern beluga whale is also the owner of a large brain weighing 2350 grams. But his “brother” bottlenose dolphin has a brain mass of only 1735 grams.
The human brain is a unique creation of nature. Indeed, in the total body mass, the share of the brain is only 2%, and to stay even in a state of “rest”, the body needs at least 9% of the energy entering the body. What can we say with the activity of thought processes! As soon as a person begins to think “strongly”, the level of energy consumption immediately increases to the level of 25%. In addition, increased brain activity requires additional oxygen supply. So while solving logical problems or writing essays, our brain “takes” up to a third of all incoming oxygen from the body.
Now we know how much the human brain weighs by itself, as well as in relation to the brain of some animals of the mammal class.
