The path to sociality

摘要

Recent discoveries related to human origins - from new fossils to ancient DNA - have stirred intense interest from scientific journals and the popular media. But perhaps more intriguing are the intimate lives of our distant ancestors. Although the steamy details may be shrouded in the mists of time, some hints about the sequence of events that led to the evolution of human social systems are emerging. The latest evidence comes from Shultz et al.1, who on page 219 of this issue trace the evolution of complex sociality within the order Primates. Their data provide a strong foundation for modelling the origins of hominid mating systems by constraining the range of likely trajectories of social change. Decades of hard work by hundreds of field researchers have provided a rich body of knowledge about the social organization of non-human primates2. Like many mammals, members of a few primate species lead a largely solitary life as adults, meeting only to mate or exchange calls at the borders of their territories (for instance, Coquerel's dwarf lemur, Mirza coquereli). By contrast, other primates are found in groups consisting of one adult male and multiple adult females (gorillas), or form large groups consisting of several males and females (baboons), or pair up to form lasting bonds and live in family groups (gibbons and humans).