The annals of field primatology are filled with stories about charismatic animals native to some of the most challenging and remote areas on earth. There are, for example, the chimpanzees of Tanzania, whose social and family interactions Jane Goodall has studied for decades; the mountain gorillas of the Virungas, chronicled first by George Schaller and then later, more obsessively, by Dian Fossey; various species of monkeys (Indian langurs, Kenyan baboons, and Brazilian spider monkeys) studied by Sarah Hrdy, Shirley Strum, Robert Sapolsky, Barbara Smuts, and Karen Strier; and finally the...