The Gelada (Theropithecus gelada), sometimes called the Gelada Baboon, is a species of Old World monkey found only in the Ethiopian Highlands, with large populations in the Semien Mountains. Theropithecus is derived from the Greek root words for "beast-ape." Like its close relatives the baboons (genus Papio), it is largely terrestrial, spending much of its time foraging in grasslands.
Phylogeny and fossils
Since 1979 it has been customary to place the Gelada in its own particular
genus (
Theropithecus), though some
genetic research suggests that this
monkey should, in fact, be grouped with its
papionine kin; other researchers have classified this species even farther distant from
Papio. While
Theropithecus gelada is the only living
species of its genus, separate larger species are known from the
fossil record:
T. brumpti,
T. darti and
T. oswaldi, formerly classified under the generic name of
Simopithecus.
Theropithecus, while restricted at present to
Ethiopia, is also known from fossil specimens found in
Africa and the
Mediterranean into
Asia, including
South Africa,
Malawi, the
Democratic Republic of the Congo,
Tanzania,
Uganda,
Kenya,
Ethiopia,
Algeria,
Morocco,
Spain, and
India. More exactly at : Mirzapur, Cueva Victoria, Pirro Nord, Ternifine, Hadar, Turkana, Makapansgat, Swartkrans.
There are two subspecies of Gelada:
Theropithecus gelada gelada
Eastern Gelada, Theropithecus gelada obscurus
Appearance
Theropithecus gelada can be physically distinguished from baboons by the bright patch of skin on its chest. This patch is
hourglass-shaped, and on
males, bright red and surrounded by white hair. On
females the patch is far less pronounced. However, when in
oestrus, the female's patch will brighten, and a "necklace" of fluid-filled
blisters forms on the patch. This is thought to be
analogous to the swollen buttocks common to most baboons experiencing oestrus. This modification likely came about due to the Gelada's unique mode of feeding - it spends most of its waking hours grazing from an upright sitting position, rump hidden beneath and so unavailable for display. The male Gelada's tail is about as long as the body and densely tufted at the tip; it also has a long and flowing mantle and mane.
Habitat and diet
Gelada live between 2,000 and 5,000 meters in the
Ethiopian Highlands, particulary
Semien Mountains National Park. They sleep on rocky cliffs and decend down to nearby grassland to forage. The Gelada is almost exclusively
herbivorous but is specialised as a
grass-eater, consuming every part of the
plant (but favouring one part over the others depending upon
season), from green blades (in the wet season) to
seeds to
rhizomes (in the dry season) to
stalks,
flowers, and
fruits. It has the most
opposable thumb of any of the
catarrhine primates (not including
humans), allowing it to pick apart grasses with great dexterity to select the most nourishing meal. It is one of the only true grazing monkeys. Biologists studying the animal in 2009 recorded an extraordinary event where the Gelada was feasting on a swarm of locust blown up from the low land valley.
Behavior
The social structure of the Gelada is similar to that of the
Hamadryas baboon. That is, Geladas live in family units made up of one male and up to ten females and their offspring. They maintain close bonds by vocally, not physically, grooming each other. They will sit around and "chatter" at each other, signifying to those around that they, in a way, matter to the individual "speaking." This is because they are continually using their hands to pull up grasses from the ground, therefore cannot devote much time to pull through the hair of others in the group. This has major implications for the origin of our own human language. The females in the groups are also closely related. If the units become too large, they will break up with the youngest females and the most dominant juvenile males leaving to form a new group. The new group stays closer to the original group, forming a band.
When the home ranges of family units overlap, they may come to together to form bands. The dominant female can monopolize the male if she wants to, but she usually does so in wild groups only when she has no alternative related female partners available.
Conservation status
Geladas are widespread throughout their present range but, partly as a result of the droughts affecting the Horn of Africa in the 1980s, they are not as abundant as in the 1970s when an aerial survey of the central Ethiopian highlands yielded an estimate of 440,000 for the total population.
[ Its population is now estimated at 200,000.][
]The overall range of the Gelada is being eroded as a result of agricultural expansion due to the increasing human population densities on the central highlands.[ Deforestation and soil erosion are serious problems throughout the area. Grazing pressure is intense, and competition from domestic livestock has forced the Gelada to remain on the less productive gorge slopes in some areas.][ There are historic records of capes being made into fur hats for tourists, but that certainly no longer occurs, and it is now extremely difficult for any tourist to leave the country with items made from Gelada skins.][ There are proposals for a new Blue Nile Gorges National Park and Indeltu (Shebelle) Gorges Reserve that would protect larger numbers..]
References
External links
ARKive - Images of the gelada (Theropithecus gelada)
Primate Info Net Theropithecus gelada Factsheet
see video
Category:Mammals of Ethiopia
Category:Megafauna of Africa
Category:Cercopithecine monkeys
Category:Animals described in 1835
