Our Brains Changed Shapes When We Met Dogs

Dog and human co-evolution happened: about 32,000 years ago.

Human brains changed shape: 35,000 to 30,000 years ago.

Modern human brain organization emerged only recently

Only fossils younger than 35,000 years show the same globular shape as present-day humans, suggesting that modern brain organization evolved some time between 100,000 and 35,000 years ago. Importantly, these shape changes evolved independently of brain size -- with endocranial volumes of around 1,400 milliliters, even the oldest Homo sapiens fossils from Jebel Irhoud fell within present-day variation of brain size. "The brain is arguably the most important organ for the abilities that make us human," says Neubauer. But modern human brain shape was not established at the origin of our species together with other key features of craniodental morphology. Neubauer adds: "We already knew that brain shape must have evolved within our own species, but we were surprised to discover just how recent these changes to brain organization were."

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