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Ethiopian
Gelada Baboon
The Semyen
highland massif is considered to be the finest scenery in all Africa
and it is for this reason, and the fact that the area is the home of
the Walia Ibex, the Semien Fox and the Gelada Baboon that it has now
been gazetted as a national park.
The Gelada is
not in fact peculiar to the Semyen as is the exclusive Walia Ibex,
but they are more numerous here than in their other habitats Some
live at Debre Sina not far from Addis Ababa and others at Debre
Libanos on the way to the Blue Nile; there are also small
populations in the Mulu and Bole Valley gorges. But in the Semyen
there may be as many as 20,000, and troops of 400 together may be
seen. They do not molest humans and, more surprisingly, the local
people do not molest them. Thus they are very tame and will allow
humans to approach quite close to the troop before moving nearer to
the cliff edge.
The Gelada was
discovered in 1835 by the explorer Ruppell, who nan;ed it by the
local name used by the inhabitants of Gonder region where he first
observed it. They are not difficult to study as they are very tame,
however, little interest was shown in them until recently, when
Patsy and Robin Dunbar made an exhaustive study of their social
behaviour. The social behaviour of the apes and monkeys is evidence
of a very high degree of intelligence and studies of their
rudimentary social structures are proving of considerable value in
analysing the origins of human social behaviour.
Geladas live
along the edges and steep slopes of precipices. They never move far
from the rim and thus their distribution is linear along the
escarpment. At night they climb down the steep cliff faces to caves
where they roost on ledges, often huddled close together for warmth
as Semyen nights are frosty and bitterly cold. Babies cling tight to
their mothers even in sleep. In the morning in the warm sun they
climb up again to the top of the cliff and spread out to feed.
Geladas are mainly vegetarian, living on herbs, grasses and roots,
but they also eat insects and locusts. They never eat meat, or hunt
or kill even small birds or mammals. As a result of this restricted
diet they are obliged to spend a very high percentage of their lives
foraging and browsing in order to obtain sufficient nutrients to
survive. This may explain why they are so extremely peaceable by
nature, with very little squabbling even amongst themselves. They
have no natural enemies (except of course, Man, who takes a fair
toll with his rifle. The great mane of the adult male is used for
traditional headresses by highland warriors).
Apart from
feeding, "grooming" is their other main pastime. This entails simply
picking through each other's fur. This is not only a friendly and
peaceful occupation, but it serves also to establish bonds between
various members of a 'harem' and to cement the accepted
relationships in the hierachy, between male and female, older and
younger members.
The long narrow
plateaus of the Semyen slope up- wards from the south until they end
in the dizzying precipices of the northern escarpment. This is the
haunt of the Walia, and the Gelada do not frequent these vertical
cliffs, but the rims of the stupendous gorges and ravines which
bisect the plateau. The troops tend to graze the higher moorlands,
amongst everlastings, giant lobelias and alchemilla-tussock grass.
Never far from the rim, which is their refuge when danger threatens,
they disappear over the edge on to the grassy slopes and ledges of
the gorge sides. Their grazing ranks are so arranged that the males
are always farthest from the edge and thus it is "women and children
first" when they have occasion to flee to safety.
They are
comparatively large and impressive, the males being about 75 cms.
(30 inches) tall without tail and twice the size of the females.
Their sad up- turned faces are marked with large ridges running from
below the outer side of the eyes to the nose. The face is dark grey
with wrinkles and very long whiskers, forming falciform tufts of
light coloured hairs projecting upwards and backwards on the sides
of the head. Their nickname, "bleeding heart baboon" stems from the
bare red skin areas on the chest, which are actual]y two triangles,
and another crescent-shaped on the throat. Both sexes have these
bare places. In the female the fleshy "beads" which surround the
bare patch swell up and turn from whitish to bright red to indicate
estrous condition. In the males the patches are always red and do
not change colour. The old males have a cape of very long hair which
hangs down (to the ground when they are sitting) and tufted tails
which have earned them another name - lion monkey. The female's mane
is much less impressive than the male's. Both sexes are a light to
dark brown, the fur cape shading from one colour to another as it
moves in the mountain breezes. They are found at more than 4,500
metres (14,600 ft.) and have even been seen at the top of Ras Dashan
at 4,620 metres (15,160 ft.) where tbere is nothing fox them to eat,
so they must just go up to look at the view.
Their handsome
appearance and the beauty of their habitat is one thing, but perhaps
the most fascinating aspect of these creatures is their social
structure which is the most complex in the animal kingdom after that
of man. You see them grouped into herds of up to 400 or so
individuals, each of which is made up in turn of "harems", which are
groups of from two to eight females and young ones with one dominant
male and often one hanger-on called a "follower", who ingratiates
himself with the juvenile females, with a view to enticing them away
in due course and forming his own harem. Harem owning males do not
attempt to steal each others' wives.
Young males get
together in groups from the age when they finally leave their
mothers until they are mature enough to become a follower. These
various social groups all move and feed together, only occasionally
leaving the herd if food supplies demand it. They travel about three
miles a day while feeding, and sleep on ledges on the cliff face
wherever they happen to be when night falls.
The harem is a
very close family unit. Ninety-five percent of the social
interactions of adults are with other members of the same harem.
Only juveniles and babies cross the invisible boundaries to play
with others of their own age. Unlike the Hamadryas baboon, where the
harem is kept together by male agression, the Gelada harem is run
more or less by solidarity between the females. It is they who
decide in which direction they will feed, it is they who instantly
rally together if their male should threaten any one of them because
she strayed too near another male! Only one of the females has a
strong relation- ship with the male at any given time. But they all
groom each other as well as him and thus establish a jealousy-free
harmonious relationship with each other.
For a young
male to acquire a harem of his own is quite a long and difficult
process. He starts off when he is about two leaving his mother's
harem in favour of play groups of other juveniles. By the age of
three he starts playing around with the younger members of the
all-male groups, and at four he things of nothing else but joining
one (which is not always easy as the groups are very tight and do
not readily welcome new members). Having succeeded he settles down
to life as a bachelor sub-adult in his group. When he is about five
or six, he begins to show an interest in the harems again. He
doesn't want to anger the adult male of any harem so he confines his
activities to following along, occasionally grooming with the male
but mainly amusing himself with the young females - the ones too
young to cause jealous feelings in the old male. Should the old male
die or become weak, the young one will take his place, but it is
more common for the youngster just to gradually withdraw taking with
him several of the young females. This is not a sudden break - the
one group just spends progressively more time on its own. The male
then sets about getting a few more females from other harems - young
females belonging to a harem with no follower may join him before
their father takes an interest in them.
Over the years
each male has a succession of followers who take away his daughters
to form the nucleus of their own harems; a system which prevents in-
breeding. Sometimes a younger male may persist in paying court to
the wives of an older, and generally harrass him. The few fights
which occur are usually the outcome of such behaviour. The old one
finally, after trying to retain his females' loyalty and affection,
may give up the struggle. If so, he does not retire from the harem -
he just adopts the follower role and spends his retirement grooming
and playing with the juveniles.
The
relationships of the Geladas are very delicately balanced. To
communicate their intentions they have need of a fairly subtle range
of signals. They have therefore acquired a great diversity of social
behaviour patterns and vocalizations. Greater in fact than any other
non-human primate. For examp]e, where the olive baboon has fifteen
contact calls, and the colobus six, the gelada makes twenty-seven
distinct noises. To hear him speak, is as it were to listen to a
foreign language being spoken. The expressions on the face are in
fact signals with a distinct meaning: the raising of the eyebrows
reveals two red triangles above the eyes - a warning signal; the
rolling back of the upper lip in a ghastly smile, a flash of red
gums and white teeth, signifies (as perhaps does the human smile)
appeasement, and thus avoids possible conflict.
So far, the
gelada is not on the endangered species list, and now that he lives
protected in at least one of his habitats, one can hope that he
never will be. How- ever, the occasional random slaughter "for fun"
of these beautiful, gentle and intelligent creatures should be
curbed for obvious reasons. |
