Gelada
Encyclopedia
The gelada sometimes called the gelada baboon, is a species
of Old World monkey
found only in the Ethiopian Highlands
, with large population
s in the Semien Mountains
. Theropithecus is derived from the Greek
root words for "beast-ape
." Like its close relatives the baboon
s (genus Papio), it is largely terrestrial
, spending much of its time foraging in grassland
s.
(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 genus 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
and Swartkrans
.
There are two subspecies
of gelada:
. There is sexual dimorphism
in this species: males average 18.5 kg (40.8 lb) while females are smaller, averaging 11 kg (24.3 lb). The head and body length of this species is 50–75 cm (19.7–29.5 in) for both sexes. Tail length is 30–50 cm (11.8–19.7 in).
The gelada has several adaptations for its terrestrial and graminivorous
lifestyle. It has small, sturdy fingers adapted for pulling grass and narrow, small incisors adapted for chewing it. The gelada has a unique gait, known as the shuffle gait, that it uses when feeding. It squats, feeds and shuffles bipedally without changing its posture, which is effective for continuous foraging. It is also because of this gait that the gelada has a bright red patch on its chest – its rump is hidden beneath and so unavailable for display.
gorge and the upper Shebelle River
valley (east of the Bale massif) mark the western and southeastern boundaries of the range, respectively. This species is associated with rocky gorges, precipices and moorland and feeds mainly on the flat margins of high grass plateaus, known locally as high Wurch or Puna grassland steppe. Geladas use cliffs for sleeping and montane grasslands for foraging. These grassland have greatly spaced trees and also contain bushes and dense thickets. The highland areas were geladas live tend to be cooler and less arid than lowlands areas. Thus the gelada does not usually experience the negative effects the dry season has on food availability. Nevertheless, in some areas, gelada do experience frost in the dry season as well as hail
storms in the wet season.
Geladas are the only primates that are primarily graminivores and grazers
– grass blades make up to 90% of their diet. They eat both the blades and the seeds of grasses. When both blades and seeds are available, geladas prefer the seeds. They also eat flowers, rhizomes and roots when available, using their hands to dig for the latter two. They also consume herbs, small plants, fruits, creepers, bushes and thistles. Insects can be eaten, but only rarely and only if they can easily be obtained. During the dry season, grasses are eaten less and herbs are preferred. Geladas consume their food more like ungulates than primates and can chew their food as effectively as zebra
s.
Geladas are primarily diurnal. At night, they sleep on the ledges of cliffs. At sunrise, they leave the cliffs and travel to the top of the plateau to feed and socialize. When morning ends, social activities tend to wane and the geladas primarily focus on foraging. They will travel during this time as well. When evening arrives, geladas do more social activities before descending to the cliffs to sleep.
. The smallest and most basic groups are the reproductive units which are made up of 1–12 females, their young and 1–4 males, and the all-male units, which are made up of 2–15 males. The next level of gelada societies are the bands which are made up of 2–27 reproductive units and several all male units. Herds consist of up to 60 reproductive units that are sometimes from different bands and last for short periods of time. Communities are made of 1–4 bands whose home ranges overlap extensively.
Within the reproductive units, the females tend to be closely related and have strong social bonds that can last longer than six months and withstand disruption that would cause reorganizations in other species. Reproductive units do split up if they get too large. While females have strong social bonds in the group, a female will only interact with at most three other members of her unit. Grooming and other social interactions among females usually occur between pairs. Females in a reproductive unit exist in a hierarchy. Higher ranking females have more reproductive success and more offspring than lower ranking females. Females that are relatively closely related have a similar hierarchical status. Females stay in their natal units for life and cases of females leaving are rare. Aggression is rare within a reproductive unit, being directed mostly towards members of other units. It is more often the females that start conflicts, but both males and females from both sides will join if the conflict escalates. Also, when there is aggression within a reproductive unit, it is usually between females.
Males can remain in a reproductive unit for 4–5 years. While geladas have traditionally been considered to have a male-transfer society, it appears that many males likely return and breed in their natal bands. Nevertheless, gelada males leave their natal units and try to take over a unit of their own. A male can take over a reproductive unit either through direct aggression and fighting or by joining one as a subordinate and taking some females with him to create a new unit. When there is more than one male in a unit, only one of them can mate with the females. The females in the group together can have power over the dominant male. When a new male tries to take over a unit and overthrow the resident male, the females can choose to support or oppose him. The male maintains his relationship with the females by grooming them rather than forcing his dominance, in contrast to the society of the hamadryas baboon. Females accept a male into the unit by presenting themselves to him. A male does not necessarily interact with all his females. He usually has a single predominant social partner. The dominant female may monopolize the male, but in wild groups this usually occurs only when no alternative related female partners are available. The male's interactions with non-partner females tend to be more perfunctory and one-sided than those with his partner female, with non-partner females showing little interest in interacting with the male.
Most all-male groups consist of several sub-adults and one young adult, led by one male. A member of an all-male group may spend 2–4 years in the group before attempting to join a reproductive unit. All-male groups are generally aggressive towards both reproductive units and other all-male units. As in reproductive units, aggression within all-male units is rare. As bands, reproductive units exist in a common home range. Within the band, members are closely related and between the units there is no social hierarchy. Bands usually break apart every 8–9 years as a new band forms in a new home range.
Most births occur at night. Newborn infants have a red face and closed eyes, and are covered in black hair. On average, newborn infants weigh 464 g. Females that have just given birth stay on the periphery of the reproductive unit, accompanied by adult females without infants; these take an interest in the infants and may even kidnap them. An infant is carried on its mother’s belly for the first five weeks, and thereafter on her back. Infants can move independently at around five months. A subordinate male in a reproductive unit may help care for an infant when it is six months old. When herds form, juveniles and infants may gather into play groups of around ten individuals. When males reach puberty, they gather into unstable groups independent of the reproductive units. Females reach puberty at around three years but do not give birth until they are four years old. Males reach puberty at around four or five years, but are usually unable to reproduce because of social constraints and have to wait until they are around 8–10 years old.
, although their population had reduced from an estimated 440000 in the 1970s to around 200000 in 2008. It is listed in Appendix II of CITES. Major threats to the gelada are a reduction of their range as a result of agricultural expansion, and shooting as crop pests. However, threats that once existed but no longer do are trapping for use as laboratory animals and shooting to obtain their capes to make items of clothing. As of 2008, there are proposals for a new Blue Nile Gorges National Park and Indeltu (Shebelle) Gorges Reserve that would protect larger numbers.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of Old World monkey
Old World monkey
The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous...
found only in the Ethiopian Highlands
Ethiopian Highlands
The Ethiopian Highlands are a rugged mass of mountains in Ethiopia, Eritrea , and northern Somalia in the Horn of Africa...
, with large population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s in the Semien Mountains
Semien Mountains
The Semien Mountains lie in northern Ethiopia, north east of Gondar. They are a World Heritage Site and include the Semien Mountains National Park. The mountains consist of plateaux separated by valleys and rising to pinnacles...
. Theropithecus is derived from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
root words for "beast-ape
Ape
Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea. The apes are native to Africa and South-east Asia, although in relatively recent times humans have spread all over the world...
." Like its close relatives the baboon
Baboon
Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger...
s (genus Papio), it is largely terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
, spending much of its time foraging in grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s.
Phylogeny and fossils
Since 1979 it has been customary to place the Gelada in its own particular genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
(Theropithecus), though some genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
research suggests that this monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
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
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of its genus, separate, larger species are known from the fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
record: T. brumpti
Theropithecus brumpti
Theropithecus brumpti is an extinct species of papionin which lived in the mid to late Pliocene.This fossil primate is mostly known from skulls and mandibles found in Pliocene deposits excavated in the Shungura Formation, at the Omo River, Ethiopia. T. brumpti, like its cousin the extant gelada ,...
, T. darti and T. oswaldi, formerly classified under genus Simopithecus. Theropithecus, while restricted at present to Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
, 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
Mirzapur
Mirzapur is a city in the heart of North India, nearly 650 km between Delhi and Kolkata and also equidistant from Allahabad and Varanasi. Located in the state of Uttar Pradesh, Mirzapur has a population of a little over 205,264 and is renowned for its famous carpet and brassware industry...
, Cueva Victoria, Pirro Nord, Ternifine, Hadar
Hadar, Ethiopia
Hadar is a village in Ethiopia, on the southern edge of the Afar Triangle with a latitude and longitude of approximately . The village is known for the nearby archaeological site....
, Turkana
Turkana District
Turkana District is an administrative district in the Rift Valley Province of Kenya. Turkana is the northwesternmost district in Kenya. It is bordered by the countries of Uganda to the west; South Sudan and Ethiopia, including the disputed Ilemi Triangle, to the north and northeast; and Lake...
, Makapansgat
Makapansgat
Makapansgat is an archeological location within the Makapansgat and Zwartkrans Valleys, northeast of Mokopane in Limpopo province, South Africa. It is an important paleontological site, with the local limeworks containing Australopithecus-bearing deposits dating to between 3.0 and 2.6 million years...
and Swartkrans
Swartkrans
Swartkrans is a location in South Africa, around from Johannesburg.Swartkrans is a farm near to Sterkfontein, notable for being extremely rich in archaeological material, particularly hominid remains. It was purchased by the University of the Witwatersrand in 1968...
.
There are two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of gelada:
- Northern gelada, Theropithecus gelada gelada
- Eastern gelada or southern gelada or Heuglin's gelada, Theropithecus gelada obscurus
Physical description
The gelada is large and robust. It is covered with buff to dark brown coarse hair and has a dark face with pale eyelids. Its arms and feet are nearly black. Its tail is shorter than its body and has a tuft of hair at the end. Adult males have a long, heavy cape of hair on their back. The gelada has a hairless face that is shorter and higher than in baboons and its snout is more like that of a chimpanzee. It can also be physically distinguished from a baboon by the bright patch of skin on its chest. This patch is hourglass-shaped. On males it is bright red and surrounded by white hair; on females it is far less pronounced. However, when in estrus, 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 estrus. In addition, females have pearl-like knobs of skin around their patches. Geladas also have well developed ischial callositiesCallosity
A callosity is another name for callus, a piece of skin that has become thickened as a result of repeated contact and friction.- Monkeys :When occurring on an animal's buttocks, as with baboons, they are specifically called ischial callosities...
. There is sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in this species: males average 18.5 kg (40.8 lb) while females are smaller, averaging 11 kg (24.3 lb). The head and body length of this species is 50–75 cm (19.7–29.5 in) for both sexes. Tail length is 30–50 cm (11.8–19.7 in).
The gelada has several adaptations for its terrestrial and graminivorous
Graminivore
In zoology, a graminivore is an herbivorous animal that feeds primarily on grass...
lifestyle. It has small, sturdy fingers adapted for pulling grass and narrow, small incisors adapted for chewing it. The gelada has a unique gait, known as the shuffle gait, that it uses when feeding. It squats, feeds and shuffles bipedally without changing its posture, which is effective for continuous foraging. It is also because of this gait that the gelada has a bright red patch on its chest – its rump is hidden beneath and so unavailable for display.
Range and ecology
The gelada is restricted to high grassland escarpments in the deep gorges of the central Ethiopian plateau, in the Tigre, Begemdir, Wolle, and Shoa Provinces between 1,800 and 4,400 m asl. The Blue NileBlue Nile
The Blue Nile is a river originating at Lake Tana in Ethiopia. With the White Nile, the river is one of the two major tributaries of the Nile...
gorge and the upper Shebelle River
Shebelle River
The Shebelle River begins in the highlands of Ethiopia, and then flows southeast into Somalia towards Mogadishu. Near Mogadishu, it turns sharply southwest, where it follows the coast. Below Mogadishu, the river becomes seasonal...
valley (east of the Bale massif) mark the western and southeastern boundaries of the range, respectively. This species is associated with rocky gorges, precipices and moorland and feeds mainly on the flat margins of high grass plateaus, known locally as high Wurch or Puna grassland steppe. Geladas use cliffs for sleeping and montane grasslands for foraging. These grassland have greatly spaced trees and also contain bushes and dense thickets. The highland areas were geladas live tend to be cooler and less arid than lowlands areas. Thus the gelada does not usually experience the negative effects the dry season has on food availability. Nevertheless, in some areas, gelada do experience frost in the dry season as well as hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
storms in the wet season.
Geladas are the only primates that are primarily graminivores and grazers
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
– grass blades make up to 90% of their diet. They eat both the blades and the seeds of grasses. When both blades and seeds are available, geladas prefer the seeds. They also eat flowers, rhizomes and roots when available, using their hands to dig for the latter two. They also consume herbs, small plants, fruits, creepers, bushes and thistles. Insects can be eaten, but only rarely and only if they can easily be obtained. During the dry season, grasses are eaten less and herbs are preferred. Geladas consume their food more like ungulates than primates and can chew their food as effectively as zebra
Zebra
Zebras are several species of African equids united by their distinctive black and white stripes. Their stripes come in different patterns unique to each individual. They are generally social animals that live in small harems to large herds...
s.
Geladas are primarily diurnal. At night, they sleep on the ledges of cliffs. At sunrise, they leave the cliffs and travel to the top of the plateau to feed and socialize. When morning ends, social activities tend to wane and the geladas primarily focus on foraging. They will travel during this time as well. When evening arrives, geladas do more social activities before descending to the cliffs to sleep.
Social structure
Geladas live in a complex multi-level society similar to that of the hamadryas baboonHamadryas Baboon
The Hamadryas baboon is a species of baboon from the Old World monkey family. It is the northernmost of all the baboons; being native to the Horn of Africa and the southwestern tip of the Arabian Peninsula. These regions provide habitats with the advantage for this species of fewer natural...
. The smallest and most basic groups are the reproductive units which are made up of 1–12 females, their young and 1–4 males, and the all-male units, which are made up of 2–15 males. The next level of gelada societies are the bands which are made up of 2–27 reproductive units and several all male units. Herds consist of up to 60 reproductive units that are sometimes from different bands and last for short periods of time. Communities are made of 1–4 bands whose home ranges overlap extensively.
Within the reproductive units, the females tend to be closely related and have strong social bonds that can last longer than six months and withstand disruption that would cause reorganizations in other species. Reproductive units do split up if they get too large. While females have strong social bonds in the group, a female will only interact with at most three other members of her unit. Grooming and other social interactions among females usually occur between pairs. Females in a reproductive unit exist in a hierarchy. Higher ranking females have more reproductive success and more offspring than lower ranking females. Females that are relatively closely related have a similar hierarchical status. Females stay in their natal units for life and cases of females leaving are rare. Aggression is rare within a reproductive unit, being directed mostly towards members of other units. It is more often the females that start conflicts, but both males and females from both sides will join if the conflict escalates. Also, when there is aggression within a reproductive unit, it is usually between females.
Males can remain in a reproductive unit for 4–5 years. While geladas have traditionally been considered to have a male-transfer society, it appears that many males likely return and breed in their natal bands. Nevertheless, gelada males leave their natal units and try to take over a unit of their own. A male can take over a reproductive unit either through direct aggression and fighting or by joining one as a subordinate and taking some females with him to create a new unit. When there is more than one male in a unit, only one of them can mate with the females. The females in the group together can have power over the dominant male. When a new male tries to take over a unit and overthrow the resident male, the females can choose to support or oppose him. The male maintains his relationship with the females by grooming them rather than forcing his dominance, in contrast to the society of the hamadryas baboon. Females accept a male into the unit by presenting themselves to him. A male does not necessarily interact with all his females. He usually has a single predominant social partner. The dominant female may monopolize the male, but in wild groups this usually occurs only when no alternative related female partners are available. The male's interactions with non-partner females tend to be more perfunctory and one-sided than those with his partner female, with non-partner females showing little interest in interacting with the male.
Most all-male groups consist of several sub-adults and one young adult, led by one male. A member of an all-male group may spend 2–4 years in the group before attempting to join a reproductive unit. All-male groups are generally aggressive towards both reproductive units and other all-male units. As in reproductive units, aggression within all-male units is rare. As bands, reproductive units exist in a common home range. Within the band, members are closely related and between the units there is no social hierarchy. Bands usually break apart every 8–9 years as a new band forms in a new home range.
Reproduction and parenting
When in estrus, the female points her posterior towards a male and raises it, moving her tail to one side. The male then approaches the female and inspects her chest and genital areas. The female then allows the male to inspect her before copulation. A female will copulate 2–5 times per day, usually around midday. Breeding and reproduction can occur at any time of the year although in some areas there are birth peaks.Most births occur at night. Newborn infants have a red face and closed eyes, and are covered in black hair. On average, newborn infants weigh 464 g. Females that have just given birth stay on the periphery of the reproductive unit, accompanied by adult females without infants; these take an interest in the infants and may even kidnap them. An infant is carried on its mother’s belly for the first five weeks, and thereafter on her back. Infants can move independently at around five months. A subordinate male in a reproductive unit may help care for an infant when it is six months old. When herds form, juveniles and infants may gather into play groups of around ten individuals. When males reach puberty, they gather into unstable groups independent of the reproductive units. Females reach puberty at around three years but do not give birth until they are four years old. Males reach puberty at around four or five years, but are usually unable to reproduce because of social constraints and have to wait until they are around 8–10 years old.
Communication
Adult geladas have a diverse repertoire of vocalizations. There are vocalizations for contact, reassurance, appeasement, solicitation, ambivalence, aggression and defense. Vocalizations are often combined into sequences. Contact calls may provide social functions. Geladas sit around and chatter at each other, signifying to those around that they matter, in a way, to the individual "speaking". To some extent, calls are related to the status of an individual. In addition, females have calls signaling their estrus. Geladas communicate though gestures as well. They display threats by flipping their upper lip back on their nostrils to display their teeth and gums, and by pulling back their scalp to display the pale eyelids. A gelada submits by fleeing or presenting itself.Conservation status
In 2008, the IUCN assessed the gelada as Least ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
, although their population had reduced from an estimated 440000 in the 1970s to around 200000 in 2008. It is listed in Appendix II of CITES. Major threats to the gelada are a reduction of their range as a result of agricultural expansion, and shooting as crop pests. However, threats that once existed but no longer do are trapping for use as laboratory animals and shooting to obtain their capes to make items of clothing. As of 2008, there are proposals for a new Blue Nile Gorges National Park and Indeltu (Shebelle) Gorges Reserve that would protect larger numbers.