Intergroup allegiances
Social arrangements in some other lemurs do not seem to be nearly as clear-cut and well-denned as in the ring-tails. The red- fronted lemur has been described as a 'social enigma' in which any kind of dominance hierarchy seems to be lacking. There does not even appear to be an unequivocal group leader, although it is almost always a female who initiates group movements around the territory. Beyond that, however, females do not seem to be at all dominant - a rare circumstance in lemur society - and usually take second place to males in things which really matter such as access to a particularly rich fruiting tree.
However, females are not always born losers and can on occasion displace a male from a favourite spot; there are simply no strict ground rules in this animal's behaviour. Interestingly enough, in well habituated groups of both the red-fronted and white-fronted lemur it is always the females who are more daring in making a really close approach to humans and the males who exhibit signs of nervousness, being the first to back off from any unexpected movement.
Allegiances within the group seem to be constantly up for grabs and so unstable that they may change back and forth within hours; the red-fronteds studied by Deborah Overdorff at Ranomafana were described by her as 'behaving like a group of teenage girls'. In the crowned lemur females win disputes most of the time, but males are not so thoroughly brow-beaten that they are unable to win now and again - unlike in ring-tails, where the uncompromisingly acquiescent males never seem to fight back. Crowned lemur groups seem to be remarkably loose affairs with no definite dominance hierarchy, although a female always seems to lead movements and both sexes scent-mark the territory as they go, using the 'standard' ano-genital application to rocks and trees.
Multi-male groups are also seen in many species of monkeys and baboons, including the black-capped capuchin, Geoffrey's spider monkey and Rhesus macaque. Howler monkey groups normally consist of one or two adult males along with several adult females, although the males' tolerance of one another may be sufficient to allow up to six to reside within a group. Relationships are hardly electrifying, with relatively little contact between group members - a trait shared with the equally vociferous indri. In these two species, both of which are on the large size for an arboreal primate, extremely loud and far-carrying singing seems to take the place of energy-demanding patrolling or fighting in effecting territorial defence.
As in the indri, howler monkey groups generally alert the broad neighbourhood to their continued presence early in the morning by giving vent to a series of deafening, rather lion-like roars; howls is scarcely the right word, despite their common name. Even so, these impressive post-dawn declarations do not always suffice to prevent neighbouring groups from chancing across one another later in the day. When this happens the scene is set for a formidable and inspiring verbal contest as the males perch high in opposing trees and roar their hearts out at one another across an intervening space of perhaps only 20-30 m or so. These oral duels may go on for as much as twenty minutes or more, representing one of the most awe-inspiring phenomena to be found in the South American forests.