A harem male grooms one of his females The basic Gelada social unit is a harem (or unimale group) made up of a dominant male and several females (1-12), their young and sometimes subordinate males. The next tier is a band that consists of several harems (usually 2-27), and this is the main social aggregation in which most Geladas spend their lives. Especially in the dry season, bands join together forming grazing herds, which can number up to 1,200 animals (although 500-600 is more normal.) Males that do not have attached females also form bachelor groups that usually associate around the periphery of the bands or herds. A harem system would indicate that the males gather and forcibly retain the affections of their females, as is the case with the savanna baboon species, but not with Geladas. The females are the ones that form the strong hierarchical bonds, often matrilineal, within the harems and they usually determine which male will become their harem "leader". For males (averaging over 40 pounds and nearly double the female weight), its all about showmanship. They strut about flicking their luxurious fur capes, roaring, displaying their massive canines, chasing off rival males and generally just releasing their built-up testosterone, but back at the ranch, it's the females that actually call the shots. In fact most of the aggression witnessed is started between females and this then draws in the males. Males maintain their relationships with their females not by dominance but by grooming them, but the females sometimes band together and attack their male if they feel he is shirking his duties by not grooming them sufficiently or not protecting them properly.