Though researchers commonly believe that humans use exceptionally large amounts of energy to power their brains in comparison to other animals, a new study from scientists at Duke University shows that may not be the case.
In the research, the team found that, while humans do use large amounts of energy for brainpower, that trait is not as unique as previously believed.
The team reached this conclusion by looking at the bony canal cross-sections of 22 different animal species, including humans, mice, monkeys, lemurs, and treeshrews. That then gave them a way to compare humans’ energy uptake to the energy uptake of other species.
Scientists found that humans do in fact use a lot more energy for brainpower than larger animals like chimpanzees and orangutans. In fact, the resting metabolic rate of the human brain uses almost three times more energy than the chimpanzee brain, and nearly five times the amount of energy than a rabbit or squirrel.
However, that difference did not stay true across all species. Researchers also found that smaller animals — including the pen-tailed treeshrew and the pygmy marmoset — use similar amounts of brainpower energy as humans.
“The metabolic cost of a structure like the brain is mainly dependent on how big it is, and many animals have bigger brain-to-body mass ratios than humans,” said lead author Doug M. Boyer, a researcher at Duke University, according to Tech Times.
The new finding challenges classic assumptions about the human brain and, as a result, could lead to new research in the field of evolution. There is a chance that more “expensive” brains may have developed when the early primates first split from the evolutionary family tree, but more trials need to be done before such claims can be made.
“We don’t have a uniquely expensive brain,” added Boyer, in a statement. “This challenges a major dogma in human evolution studies.”
The study is published in the Journal of Human Evolution.