common ancestor our closest living relatives chimpanzees eastern chimpanzee Our Closest Living Relative, the Chimp chimpanzees our closest living relatives, chimpanzees evolutionary pressures close relatives bonobos' sex calls eastern chimpanzee humanity's closest living relatives chimpanzees and humans chimpanzees and humans our closest living relatives common ancestor humans' closest living relatives eastern chimpanzee chimpanzees our closest living relatives our closest living relatives closest living animal relatives our closest living relatives bonobos' sex calls chimpanzees and humans our closest living relatives common ancestor chimpanzees our closest living relatives our closest living relatives chimpanzees our closest living relatives chimpanzees and humans evolutionary pressures chimpanzees and humans chimpanzees humanity's closest living relatives