1 female, multiple males, each male mates only with that female. Many callitrichids (tamarins and marmosets); golden lion tamarin. 1 male, multiple females, each female mates only with that male. Colobus monkey, patas monkey, gelada baboon, hamadryas baboon, gorilla. Males and females mate with multiple individuals of the opposite sex. Also called multi-male, multi-female mating system or promiscuous mating system. Chimpanzee, savannah baboon, brown lemur, sifaka, ring-tailed lemur. Individuals only come together to mate and do not live in permanent social groups. Mating system and social system not always the same thing. Sexual maturity, longer gestation period, longer infant dependency, longer lives. Copulation used in many social contexts (lesson tension, reconcile, as a greeting); same-sex copulations are also common. Semi-solitary except when mating, when food is abundant, or in mother/child groups. Males have cheek flanges which females lack; only the most dominant male in a general area will have it - male bimaturism.