Vervets and Somangos

When I lived in Imbeza Valley, in eastern Zimbabwe, vervet monkeys plagued and fascinated me.  Up in the Vumba mountains, where I later moved, I pit my wits against somangos.  Observing and comparing the two species is, I have discovered, a totally absorbing way of wasting time.

Adult vervets weigh about 4 ½ to 8 kilograms, against the somangos’ 7 to 9 kgs or more.  The former are a fairly uniform sandy grey, almost white over the brows and cheeks and on the belly, with darker hands, feet and tail-ends, and have cute little black, shield-shaped faces.

Somangos are a darker grey, verging on blue – in fact they are commonly known as blue monkeys – with black limbs, hands, feet and tails and a patch of russet at the tail head.  They have heavier, uglier profiles than vervets, with bushy eyebrows that make even their babies look like wizened old men.

Because vervets live where man wants to live, in savanna and woodland suitable for development, they are universally and unmercifully persecuted, their habitat systematically destroyed.  Consequently they have become, for the most part, a vicious, cunning lot, observant and adaptable.

Discipline in the vervet troop is strict.  Infants must obey their mothers instantly or risk a nip and a clout, and the whole troop must obey the dominant male.  It is he, it would seem, who decides where they will feed, when to remain in an area, when to move on, when to hide, when to flee, when to sleep.  He tolerates all the other males in his troop, provided they remain subordinate to him, but heaven help any strange male who comes near.

The one- to two-year olds, finding their mothers occupied with new infants, form mischievous “teenage gangs”, play rough-and-tumble games, tease their elders and let curiosity win over the elders’ warnings. The mortality rate in this group is high.  They fall more often than one would imagine, sometimes fracturing limbs.  But, like cats and other fine-boned, quick-nerved animals, they heal rapidly.

Territorial boundaries are known to the very tree, and disputes seem more often to concern the straying individual than the outright challenge.  If, however, as often happens, a troop is forced by human activity to forsake its territory and enter that of another, fighting can be bitter and prolonged, the harassed troop tragically caught between the devil and the deep.

At the forest edge...

Somangos are confined to our high, evergreen forests and this one fact is responsible for most of the psychological and sociological differences between them and the vervets.  Their habitat has not, as yet, been as extensively exploited by man as has the woodland.  Therefore the somangos are not persecuted as relentlessly as the vervets are.  While being quick and clever enough, they have not the need for same downright cunning.  They are noticeably less vicious and quick-tempered.  Their taller, denser trees afford them greater protection from all predators so troop discipline does not have to be too severe.  The warning shout of the somango is often more of a take-note quality than an imperious command.

Among the somangos this warning bark  is only made by the dominant male, except on the rare occasion  when the danger is great and an up-and-coming male finds himself at a safe enough distance from the boss to give a quick shout of his own.  This would lead one to deduce that there is only one adult male in a troop, which would be incorrect.  When disturbed, all the males in a troop of vervets give their warning cries and in this way one can get at least an idea of the ratio of males to females.

Like the vervets, somango youngsters also form gangs, getting up to every form of mischief.   Their games are even more uninhibited than those of their vervet counterparts and they make prodigious leaps.  They fall even more often but seldom come to harm because of the closely spaced trees and layers of overlapping branches below them.  For all this, it is the vervets that are the more successful species.

Somangos and vervets have common enemies – humans and dogs, leopards, eagles and pythons.  But by far the most devastating is the destruction of habitat.  The somangos are not able to adapt to changed conditions as readily, if at all, as the vervets, hence their more rapid decline.

Somango territorial boundaries are well-respected but there does seem to be a fair bit of straying by individuals.  It has been suggested that such individuals might be peripheral males from neighbouring troops raiding for females.  This may be so, yet how would the raider induce the female of his choice to go away with him?  Perhaps his objective would be merely a brief mating.  One’s observations are always greatly hampered by the height at which these monkeys live and the dense foliage.

The languages of the two species are fairly similar in some respects. The warning clickings of the females and barks of the males; the low sound followed by the incredibly high note of a young one calling its mother; the frustrated squeals of a youngster as its mother attempts to wean it; the loud, widely-spaced clicks of an adult who has become separated from the troop; the ‘comments” when a hawk, allied to their arch-enemy the eagle but in itself not dangerous, passes nearby; the soft, guttural greetings – all these are different in dialect rather than phrase.  Incidentally, several such sounds can also be recognised in baboon talk.

The somangos, however, have many sounds – chirrups and peeps – that would be quite impossible for the human voice to imitate without some form of mechanical aid.  Their need for secrecy and alertness being less demanding, somangos are more conversational than vervets.  It would take a great deal of study before their wealth of “words” could be accurately translated.  Besides the almost constant mutterings and whistles, virtually every occurrence such as a change in the wind, the sight or sound of another animal even though familiar, the sound of a branch breaking or a tree falling, and especially the warning shout by the male of some distant troop, are all commented upon.

Both species are omnivorous, relishing a wide variety of seeds, fruit, buds, flowers and leaves, insects, grubs and birds’ eggs.  Both are daring raiders of crops and orchards.

Much animosity felt towards monkeys is due to what would seem to be, by human standards, such wasteful feeding habits.  Typically, monkeys take a few mouthfuls and let the rest of the food slip from their hands.  Monkeys are not the only ones to do this, of course.   Birds and squirrels can be even worse.  But in the natural way of things this is a very useful habit.  For buck, bushpigs, servals, civets, mongooses, rats and mice, tortoises, chongololos and more, this is about the only way to obtain reasonably fresh fruit and tree seeds.  Some of these animals follow the feeding troops to pick up such delicacies as they fall and even strike up a friendship with each other.  In my forest I often watch somangos and bushbuck chasing around after each other, taking turns in pursuing and being pursued.  They will play tag round and round a tree until all the undergrowth is flattened in a circle.

Mongooses also play with the somangos.  The way a mongoose asks to be groomed, lying stretched out, arm above head, eyes half closed in expectation, is immediately recognised by the monkeys and responded to.  Sometimes the mongooses nip – and get their tails tweaked in return.  All this means that the monkeys must play on the ground, but my forest is a reasonably safe place now and they play with abandon and a great deal of noise.

Young monkeys show a touching tenderness and curiosity towards new infants born to their troop.  At first the mothers, while allowing them to touch noses as they take turns to visit and admire the new arrival, fend off with a forearm any attempts to fondle it.  It is the other matrons who are trusted first, then the baby’s siblings.

In front of my house there is a flat-topped thorn tree much favoured by the somangos.  The many branches, twigs and leaflets form a thick mattress on which the young – and not so young – love to bounce.  Here the mothers gather and, since it would be virtually impossible to fall through this canopy, allow their infants to take their first tentative steps.  These babies toddle to one mother after another and are cuddled by all, but at the least sign of danger I notice the mother’s hands fly out to their own offspring only.  A little later the older siblings are allowed to sit quietly by the mother’s side and play with the new baby.  Like human children, when they see the little one suckling, these siblings sometimes want to suckle too, especially as darkness gathers round them, and throw screaming tantrums when prevented from doing so.

Strangler fig - somango country

[I remember that acacia tree, which my second-storey bedroom window overlooked; one day an outburst of distinctive “Eagle! Close!” somango cries made me look up from my desk just in time to see a Crowned eagle swoop across the tree-top and away with a little somango haplessly thrashing in its great claws.  The tree fell eventually, depriving us of a great viewing-platform. – Dan Wylie]

As they grow older a certain amount of fighting occurs, mostly confined to threatening postures and verbal abuse.  Perhaps they establish some sort of “pecking order”, for some individuals seem to consistently avoid certain others.  More serious fighting takes place when the dominant male’s leadership is challenged by a younger male.

When I first came to this place, Wildwoods Sanctuary, the resident somango troop numbered about sixty, which is a lot.  The boss monkey was an immense animal, well above the average weight.  I called him “Watch”.  There was no knowing how long he had been the leader but he was well established at that time.  At first he kept his troop well out of our way, until he came to understand that no one here would shoot or throw stones at them, nor the dogs bark and chase them.  It was quite safe for them to relax in the garden, play on the roof and nurse their babies in the thorn tree.

For the next six years Watch reigned supreme, magnificent and arrogant.  During the seventh year he was challenged by a younger male who, while as yet lighter than old Watch, showed promise of even greater growth.

The war raged on and off for several months.  Trees shook and branches broke under the contestants.  From what I could see there was not a great deal of physical contact, in spite of their enormous fangs and undoubted strength.  The idea seemed to be to run the other off the end of the highest possible branch; the younger monkey, being the lighter, had the advantage here.  I was relieved when old Watch survived battle after battle, but in the end the challenger won.

Overlooking the Ravine, Wildwoods

The troop’s territory sweeps up the mountain from east to west.  On the west and north sides the evergreen forest gives way to msasa woodland not very suitable for their everyday living.  To the south lies the parallel territory of another troop.  So it was to the high eastern boundary, by what we called Leopard Forest and the rocky Ravine, that Old Watch was forced to go.  Lost to him were his life-long companions, our sweet orchard fruits and the protection from predators that proximity to the house had afforded.

He would not accept it.  His towering fury was uncontainable.  He could be heard raging through the forest from afar, thrashing trees and breaking great branches, day after day.  I felt intensely sorry for him and hoped that when his temper cooled and he became less dangerous he would accept me again as a fellow forest-dweller and perhaps not so lonely.

He had a better idea.  One windy day he came quietly and unobtrusively down to where the troop, scattered around the bogs, was feeding and dozing, and when he left all the mature females, most of whom were at that time pregnant, went with him.  I would love to know how he rounded them up and got them to follow him without Young Watch being aware of it.  He had been their leader for years and I suppose that when he said, “Come on, let’s go!” in the old way, they obeyed him out of habit.  In any event, he now had a small but viable troop, with a whole generation about to be born, while his rival had to wait another full year before any of his females were old enough to breed.

It will be several years before any male in Old Watch’s troop will be grown enough to replace him and I doubt if the old warrior will last that long.  I visualise his family eventually drifting back to rejoin the others.  Meanwhile I sometimes take him wind-fall fruits from the orchard for old times’ sake.  And with respect and understanding I salute him.