CERCOPAN

Category: Cercopan, Conservation, Monkeys, Rain Forests | Date: Jun 03 2008 | By: cercopan

Here is another blog from Sagan, our Mangabey researcher….

With 40 mangabeys living together in 1 hectare, social interactions are endless.  As I am now able to recognize all individuals within the group, I cannot help but to be overly intrigued by the dynamics of the family.

Sagan Observing the group

The adult females are the central hub of the group.  The males spend much of the day fighting over them and many of the juveniles still rely on them as a source of milk, comfort, and protection.  In a seemingly peaceful manner, the females spend much of their day looking for food and grooming. They hardly seem to notice the havoc the males and juveniles create around them.  And it is plenty!  During periods of intensified sociality, the dominant female Odudu moves across the population grooming animals for short periods inspecting their wounds.  These short grooming bouts seem to be her way of making sure everyone is happy and re-affirming her position in the group.  She is a graceful and charismatic monkey, and with half of the population descended from her, she is truly the mother of the group.

Odudu and some members of her family

The males on the other hand expend their energy quite differently.  Though they do spend time grooming and caring for offspring, their efforts tend to be directed towards mate acquisition and guarding. When females in the group are cycling (adverstised via large pink sexual swellings) the aggression in the group noticeably increases.  The female will forage her way through the day as usual, but at this time she will be followed by one or more males.  At peak swelling (when she is most fertile), these follows can last all day.  When there is more than one interested male, the lower ranking male follows most closely and will in turn be followed by a higher ranking male.  And if she is particularly sexy, sometimes a third male will join in and follow her and the two other males.  The male mangabeys are certainly dedicated to the cause!  The pattern of interactions throughout the day is quite repetitive with the higher ranking male chasing off the lower ranking individuals whenever they get too close to the female.  I imagine this strategy is a way for the dominant male to limit the number of matings by lower ranking males without needing to exert physical forms of violence. 

Clyde, the dominant male of the group

Compared to the large amount of chasing and loud screaming vocalizations throughout the day, the amount of physical fighting and thus injury is relatively low (though some nasty injuries do occur!). When more than one female is swelling it becomes difficult for a dominant male to monitor.  If the dominant male slacks in his vigilance the lower male will seize the opportunity (if the female permits!).    Last month we had 5 adult females swelling at once!  It is during such times that lower ranking males have an opportunity to mate and possibly sire some offspring.  The specific strategy used by females to ensure that their offspring are sired by the most fit male is unknown.  We hope to be able to paternity tests within the group in order to determine who is actually fathering the juveniles in this ever so growing population.  Such information is also useful in investigating whether inbreeding avoidance mechanisms are being upheld in a growing isolated population.

Odudu and adult male Sunday

When the group is faced with periods of seemingly endless sex and violence the juveniles do their best to stay out of the way.  Meanwhile, some of the older individuals will sometimes join in to try and establish their spot within the group.  It is a critical time in the group at the moment as we have several growing males that will soon become adult.  In the wild males disperse from their native group to find a new group full of unrelated females.  As this is not possible within our semi-captive group we are curious to see what will happen.  Otu, a 7 year old male and Odudu’s son, is the first male to become adult within the group.  For now, he keeps on the periphery of the group (though he doesn’t seem to be low ranking).  This may be a result of his inability to disperse.  Will he establish his own splinter group formed of unrelated females?  Or is he bound to be an outcast?  This situation is particularly interesting as it can be used as a model for growing wild populations that are isolated in forest fragments created by deforestation.  We are all very curious to see what happens, and very keen for some of these managbeys to be released!