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.