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Smarter Brains Are Blood-Thirsty Brains

Smarter Brains Are Blood-Thirsty Brains

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A University of Adelaide-led project has overturned the theory that the evolution of human intelligence was simply related to the size of the brain -- but rather linked more closely to the supply of blood to the brain.

The international collaboration between Australia and South Africa showed that the human brain evolved to become not only larger, but more energetically costly and blood thirsty than previously believed.

The research team calculated how blood flowing to the brain of human ancestors changed over time, using the size of two holes at the base of the skull that allow arteries to pass to the brain. The findings, published in the Royal Society Journal Open Science, allowed the researchers to track the increase in human intelligence across evolutionary time.

Segments of the internal carotid artery at the base of the skull that allow arteries to pass to the brain, delineated on an MRA of the head.

Segments of the internal carotid artery at the base of the skull that allow arteries to pass to the brain, delineated on an MRA of the head. (CC BY-SA 3.0)

"Brain size has increased about 350% over human evolution, but we found that blood flow to the brain increased an amazing 600%," says project leader Professor Emeritus Roger Seymour, from the University of Adelaide. "We believe this is possibly related to the brain's need to satisfy increasingly energetic connections between nerve cells that allowed the evolution of complex thinking and learning.

"To allow our brain to be so intelligent, it must be constantly fed oxygen and nutrients from the blood.

"The more metabolically active the brain is, the more blood it requires, so the supply arteries are larger. The holes in fossil skulls are accurate gauges of arterial size."

Arteries at base of brain and spine.
Arteries at base of brain and spine. (CC BY 4.0)

The study was a new collaboration between the Cardiovascular Physiology team in the School of Biological Sciences at the University of Adelaide and the Brain Function Research Group and Evolutionary Studies Institute at the University of the Witwatersrand.

Co-author Dr Edward Snelling, University of the Witwatersrand, says: "Ancient fossil skulls from Africa reveal holes where the arteries supplying the brain passed through. The size of these holes show how blood flow increased from three million-year-old Australopithecus to modern humans. The intensity of brain activity was, before now, believed to have been taken to the grave with our ancestors."

Honours student and co-author Vanya Bosiocic had the opportunity to travel to South Africa and work with anthropologists on the oldest hominin skull collection, including the newly-discovered Homo naledi.

Dinaledi skeletal specimens.

Dinaledi skeletal specimens. (CC BY 4.0)

"Throughout evolution, the advance in our brain function appears to be related to the longer time it takes for us to grow out of childhood. It is also connected to family cooperation in hunting, defending territory and looking after our young," Ms Bosiocic says.

"The emergence of these traits seems to nicely follow the increase in the brain's need for blood and energy."

Top image: These are skull casts from human evolution. Left to right: Australopithecus afarensis, Homo habilis, Homo ergaster, Homo erectus and Homo neanderthalensis. Credit: Roger Seymour. Casts photographed in the South Australian Museum.

The article ‘Smarter Brains Are Blood-Thirsty Brains’ was originally published on Science Daily.

Source: University of Adelaide. "Smarter brains are blood-thirsty brains." ScienceDaily. ScienceDaily, 30 August 2016.



A recent study in the Southwest was conducted on thousands of Ancient “Metates” used for grinding Grains, Seeds and Beans by the "Nomadic” Tribes. Knowing for sure that the Natives out here were primarily Vegetarians they wanted to see for sure what species of Flora they were indeed consuming. But what they found was that there was very very little Flora Residue and ALL the samples contaned mostly Rodent and Reptile Residue. They ground them into a Paste, made Cakes and cooked them on Hot Rocks. Surprise...Surprise…

Man would have went extinct a long time ago if they were forced to depend on mostly Flora.  50,000 years from now that new human species with very low IQ’s and the tiny heads running around trying to force everyone to stop eating Meat will be those newly classified as “Homo Vegansis”.

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