Final answer:
The bonobo, known as the pygmy chimp, uses sexual behavior as a means to maintain peace and avoid conflict in their egalitarian and female-dominant societies, contrasting with the male-dominated structures seen in closely related chimpanzees.
Step-by-step explanation:
The primate commonly known as the pygmy chimp is the bonobo (Pan paniscus). Bonobos are known for using sexual behaviors to maintain social harmony and avoid conflict within their groups, leading to their nickname as the "make love, not war" primate. Unlike their close relatives, the chimpanzees, which have a male-dominant and hierarchical society, bonobo groups are more egalitarian and female-dominant. This distinction in social structure is also reflected in their sexual behaviors, where bonobos engage in frequent and varied sexual activities with both same-sex and opposite-sex partners. The role of sex in bonobo society is thought to help build social bonds and ease tensions, thus contributing to their more peaceful lifestyle.
In terms of sexual dimorphism, which describes the size difference between males and females within a species, bonobos present a lower level compared to other primates like gorillas. Sexual dimorphism is often linked to the social dynamics within primate species, with high levels generally associated with strong male dominance and rigid hierarchies, while lower levels may indicate more monogamous or egalitarian relationships like those seen in bonobos and gibbons.