In fi elds as diverse as particle physics and cultural anthropology, it has been noted that the very act of scientifi c observation affects that which is being observed. Certainly this would also be the case for the ethological observation of nonhuman primates. What are the scientifi c as well as the ethical implications of this idea? Are some of our scientifi c ideas potentially inaccurate? Has studying other primates in the wild been in any way detrimental to them? benefi cial to them?