Colleen M. Schaffner & Nancy G. Caine
Many researchers have provided information that supports the impression that callitrichids (tamarins and marmosets) lead a pacific group life. Callitrichids are highly cooperative: all individuals within a group share in a variety of tasks that include searching for and consuming food, antipredator detection and mobbing, defense of the home territory, and shared care of offspring. These well-documented characteristics suggest that marmosets and tamarins are not only cooperative but also nonaggressive and that family life is peaceful. However, high levels of cooperation are not necessarily exclusive of aggression. In our chapter we present data on the rates and forms of aggression in three species, representing three of the fourcallitrichid genera. We also present an analysis of post-conflict behavior that sheds light on the consequences of aggression. Finally, we explore the role of reproductive inhibition as a proximate mechanism for maintaining low aggression and in turn facilitating cooperation in callitrichids.
The primate family Callitrichidae is composed of approximately 30 distinct species within four genera (Rylands et al. 1993). Callitrichids include the diminutive pygmy marmosets (Cebuella); the Callithrix marmosets, which include 10 to 12 distinct species; the Saguinus tamarins, which include 12 recognized species (Fig. 8.1), and four species of lion tamarins (Leontopithecus). Although the callitrichid group represents a large number of species, there are a variety of taxonomic characteristics that distinguish them from other New World primates.