Biological anthropologist Alice Roberts discusses why humans evolved large brains and upright walking. Physically, Homo sapiens resembles other animals yet has adapted to survive across diverse environments from forests to polar regions. Roberts began in medicine as a surgeon and anatomist before focusing on the evolutionary path of bipedal, speaking apes. She now serves as professor of public engagement in science at the University of Birmingham, with work spanning anthropology, archaeology and palaeopathology. She has presented numerous television series and edited the book Humans, which covers human evolution through illustrations and contributions from an international team. In conversation, Roberts described how teaching anatomy alongside veterinary students led her to view humans as another mammal species. She noted that cellular biochemistry traces back to early single-celled life in ancient seas, while limbs reflect changes from fins about 360 million years ago. Comparing bones such as the humerus or hands reveals both similarities and subtle differences with other primates. Roberts highlighted bipedalism, reduced tooth size and expanded brains as defining traits, though the precise links between upright posture and brain growth remain uncertain. She also pointed to roughly twenty known hominin species, including overlaps with Neanderthals, which have altered views of our evolutionary history.
