Brain Comparison (IMAGE) Howard Hughes Medical Institute Caption Roughly three million years ago, human brains began to expand. Today, the human neocortex is larger than that of an orangutan, gorilla, or chimpanzee, our closest living primate relative. Scale bar equals 5 centimeters. Credit I. Fiddes et al./Cell 2018. Gary Mantalas took the photos of skulls that were provided by Richard Baldwin of the Anthropology Department at UCSC. Usage Restrictions Use with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.