The Bale Mountains vervet (''Chlorocebus djamdjamensis'') is a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

Old World monkey Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...

, found in the

bamboo Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, bu ...

forests of the

Bale Mountains The Bale Mountains (also known as the Urgoma Mountains) are mountain ranges in the Oromia Region of southeast Ethiopia, south of the Awash River, part of the Ethiopian Highlands. They include Tullu Demtu, the second-highest mountain in Ethiopia ...

. All species in ''

Chlorocebus ''Chlorocebus'' is a genus of medium-sized primates from the family of Old World monkeys. Six species are currently recognized, although some people classify them all as a single species with numerous subspecies. Either way, they make up the enti ...

'' were formerly in the genus ''

Cercopithecus The guenons (, ) are Old World monkeys of the genus ''Cercopithecus'' (). Not all members of this genus have the word "guenon" in their common names; also, because of changes in scientific classification, some monkeys in other genera may have co ...

''. The Bale Mountains vervet is one of the least-known primates in Africa. They avoid tree-dominated and bushland areas as their habitat. These monkeys mainly reside in the bamboo forest (Odubullu Forest) of the Bale Mountains due their dietary specialization on bamboo, but other factors, such as climate, forest history, soil quality, and disease, are likely to play a role in their choice to inhabit this area. The Bale Mountains vervet have a very quiet behavior and tend to flee when encountering a human being. It is also known as the Bale monkey.

Taxonomy

The Bale monkey is a member of genus ''

'', along with five

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

. All members of ''Chlorocebus'' were formerly considered to be part of ''

''; the Bale monkey was formerly known as ''Cercopithecus djamdjamensis''. It was originally described as a subspecies of the

grivet The grivet (''Chlorocebus aethiops'') is an Old World monkey with long white tufts of hair along the sides of its face. Some authorities consider this and all of the members of the genus ''Chlorocebus'' to be a single species, ''Cercopithecus ae ...

(''Chlorocebus aethiops''). A 2018 study found that the populations of Bale monkey living in fragmented forests were genetically distinct from populations in continuous forests. This is due to the fragmented forest populations'

hybridization Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

with the

(''Chlorocebus aethiops'') and the

vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...

(''Chlorocebus pygerythrus'').Mekonnen, A., Rueness, E.K., Stenseth, N.C. ''et al.'' Population genetic structure and evolutionary history of Bale monkeys (''Chlorocebus djamdjamensis'') in the southern Ethiopian Highlands. ''BMC Evol Biol'' 18, 106 (2018). https://doi.org/10.1186/s12862-018-1217-y The Bale monkey does not currently co-occur with either of these monkeys in the wild and so it is proposed that this hybridization occurred over a century ago.

Ecology

The Bale Mountains vervet monkey is a

dietary In nutrition, diet is the sum of food consumed by a person or other organism. The word diet often implies the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are o ...

specialist with

African alpine bamboo ''Oldeania alpina'', the African alpine bamboo, is a perennial bamboo of the family Poaceae and the genus ''Yushania''. It can be found growing in dense but not large stands on the mountains and volcanoes surrounding the East African Rift betwee ...

(''Yushania alpina'') making up as much as 77% of its diet.Mekonnen, A., Fashing, P.J., Bekele, A. ''et al.'' Dietary flexibility of Bale monkeys (''Chlorocebus djamdjamensis'') in southern Ethiopia: effects of habitat degradation and life in fragments. ''BMC Ecol'' 18, 4 (2018). https://doi.org/10.1186/s12898-018-0161-4 This makes the species unique in the genus ''

'' as the other five species are dietary

generalist species A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (for example, a heterotroph with a varied diet). A specialist species can thrive only in a narrow range of env ...

. The diets of Bale monkeys in continuous forests are made up of approximately 10 species of plants; however, populations in fragmented forests have considerably higher dietary diversity and consume up to five times more species. For those populations, bamboo makes up as little as 2% of their diet. It is unclear if this dietary flexibility is due to hybridization from

and

vervet The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...

monkeys or if the species adapts in the absence of bamboo. This dietary flexibility makes the Bale monkey less dependent on its main food source than other dietary specialist species like the

koala The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the womb ...

giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear (or simply the panda), is a bear species endemic to China. It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes us ...

. In areas where Bale monkeys and

human settlements In geography, statistics and archaeology, a settlement, locality or populated place is a community in which people live. The complexity of a settlement can range from a minuscule number of dwellings grouped together to the largest of cities ...

co-occur, the monkeys often raid

crops A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydroponics ...

for food which can spark retaliatory hunting.

Conservation status

The Bale monkey is currently rated vulnerable by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

and is listed on Appendix II of

CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...

. The main threats to the species are

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and hunting. They could be threatened by

with the

and the

in the future. The monkey feeds on

and may thus be threatened by

deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...

. Encroaching human populations have nearly extirpated the Bale monkey from the Sidamo Highlands. The monkey is persecuted for crop raiding and hunted by local people. It is protected in parts of its range by the

Bale Mountains National Park Bale Mountains National Park (BMNP) is a national park in Ethiopia. The park encompasses an area of approximately in the Bale Mountains and Sanetti Plateau of the Ethiopian Highlands. The park's Afromontane habitats have one of the highest incid ...

; the proposed Harena-Kokosa National Forest Reserve would protect some populations.

References

Bale Mountains vervet The Bale Mountains vervet (''Chlorocebus djamdjamensis'') is a terrestrial Old World monkey endemic to Ethiopia, found in the bamboo forests of the Bale Mountains. All species in ''Chlorocebus'' were formerly in the genus ''Cercopithecus''. The B ...

Mammals of Ethiopia Endemic fauna of Ethiopia Bale Mountains Fauna of the Ethiopian Highlands Vulnerable animals Vulnerable biota of Africa

Taxa named by Oscar Neumann {{oldworld-monkey-stub