Chimpanzees, top right: Corbis / ​ Punchstock / ​ Getty Images; lower left and right: SuperStock RF / ​ SuperStock; Jane Goodall: © Martin Engelmann / ​ age fotostock
Chimpanzees, top right: Corbis / ​ Punchstock / ​ Getty Images; lower left and right: SuperStock RF / ​ SuperStock; Jane Goodall: © Martin Engelmann / ​ age fotostock