Two goals in the study of evolutionary anthropology are to determine the factors that make humans unique and to reconstruct the evolution of our behavior. As humans' closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) have always been of special interest in this regard. Because of their close evolutionary relationship to us, these animals provide the requisite comparative data to evaluate claims made about human uniqueness. In addition, knowledge of the differences among chimpanzees, bonobos, and us furnishes important insights into the changes that occurred during human evolution. Given these circumstances, studies of chimpanzees and bonobos remain high priorities for research. The volatile political situation in the Democratic Republic of the Congo, home to bonobos, has made long-term study of their behavior difficult, if not impossible. In contrast, field research on chimpanzees, initiated by Jane Goodall1 and Toshisada Nishida2 nearly 50 years ago, continues to grow and thrive. While past and ongoing field work has added enormously to our understanding of the behavior of chimpanzees,3–8 gaps in knowledge persist. In this paper, I summarize some of these gaps, giving special emphasis to male cooperation and female competition.