A Century-Old Assumption Challenged
Uncovering the Rule-Breakers
For over a century, scientists believed that brain size increased proportionally with body mass. However, groundbreaking research from the University of Reading and Durham University has upended this notion, revealing that the relationship is not linear but curved. This means that larger animals tend to have smaller brains than expected.
Published in Nature Ecology & Evolution, the study identified ‘rule-breakers’—species that don’t conform to the expected brain-body size pattern. Homo sapiens stands out, evolving over 20 times faster than other mammals. However, humans aren’t alone in defying trends. Bats, for instance, rapidly reduced their brain size upon evolving flight, likely due to the energy constraints of aerial movement.
The Energy Barrier to Bigger Brains
The study found that primates, rodents, and carnivores show the fastest changes in brain size over time, but there’s a limit. Beyond a certain size, brains demand too much energy to sustain. Similar patterns in birds suggest this constraint is a universal evolutionary principle.
Cracking the Mystery of Brain Size Evolution (Source: https://www.durham.ac.uk/departments/academic/anthropology/news/anthropologists-solve-brain-size-riddle/