‘Big-brained’ mammals may just have small bodies, study suggests

Examination of 1,400 living and extinct species finds evolutionary selection may not be reason for larger brains

Big-brained mammals are typically considered intelligent - but a study has found that the body size of a species could have evolved smaller to adapt to environmental changes, making the brain appear proportionally bigger. In other words, relative brain size may have nothing to do with being clever after all.

By examining data underpinning the brain and body size of 1,400 living and extinct mammal species over the last 150m years, a cohort of researchers set out to investigate whether it is possible to predict how big a mammal's brain will be based on its body size.