Not the biggest glutton
Scientists have refuted the myth of the record "voracity" of the human brain
The human brain is inferior in "voracity" to the brain of many monkeys, lemurs and even tupai – primitive relatives of primates. This casts doubt on the hypothesis that human evolution was "conducted" by the growth of his brain, according to an article published in the Journal of Human Evolution.
"We have shown that a person does not have a uniquely "voracious" brain. This calls into question one of the cornerstones of modern anthropology and the history of human evolution," said Doug Boyer from Duke University in Durham (in a press release, Humans don't use as much brainpower as we like to think – VM).
One of the main mysteries in the history of human evolution is how our ancestors were able to acquire such a large and "voracious" brain that consumes about a quarter of the energy produced by the body. As observations of gorillas and chimpanzees show, in principle they cannot have such a large brain, because in this case they would have to eat around the clock.
Therefore, almost all scientists believe that the evolution of man as a whole is due to the growth of the size of the brain. Its increase led to the emergence of the ability to use tools and cook food, which helped our ancestors to provide their nervous system with the necessary energy.
Boyer and his colleague Arianna Harrington suggested that these ideas are fundamentally wrong by comparing how many calories the human brain receives compared to the rest of the body, and a similar parameter for 15 species of primates, rodents and other mammalian species.
In these measurements, scientists were guided by a very simple consideration – the source of glucose and other nutrients for all organs, including the brain, is blood. The higher the energy requirement, the more blood needs to be delivered to the organ and the wider and more numerous the blood vessels will be.
Their width, in turn, will be related to how the lower part of the skull is arranged and the vessels are distributed along the neck and other parts of the body involved in the supply of blood to the brain. This allows you to calculate the typical and peak amount of energy that the human or animal body spends on supplying the brain.
These measurements and comparisons led to rather strange results. On the one hand, Harrington and Boyer confirmed that the human brain actually consumes about two to five times more energy (adjusted for weight difference) than the nervous systems of chimpanzees, mice, squirrels and rabbits.
On the other hand, many other animals, including less "advanced" species of monkeys and even lemurs and tupayas, turned out to have even more "voracious" nervous systems than humans. All these species have never been considered "intellectuals" among animals, therefore, as Boyer notes, no one has tried to study them before when analyzing the history of human evolution.
Such results, according to biologists, suggest that the picture of human evolution may turn out to be completely the opposite of what anthropologists draw – perhaps it was not the increase in the brain that influenced the acquisition of the ability to make tools and use them, but on the contrary – these skills forced human ancestors to "grow" the brain.
You can test this idea if you find the remains of ancient people not only with individual fragments of skull bones, but also cervical vertebrae. The reconstruction of the blood supply system, scientists conclude, will help to understand whether our ancestors were more like chimpanzees and gorillas or humans, monkeys and the most primitive primates.
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