Fermentation may have driven human brain evolution

The large, capable human brain is a marvel of evolution, but how it evolved from a smaller primate brain into the creative, complex organ of today is a mystery. Scientists can pinpoint ‘when’ our evolutionary ancestors evolved larger brains, which roughly tripled in size as human ancestors evolved from the bipedal primates known as Australopithecines. But ‘why’ it happened when it did—what spurred that change—has remained elusive.