Black colobus group (genus Colobus) and the Olive Colobus Monkey

Angola Colobus Monkey

The Angola colobus is also known as the Angolan black-and-white colobus, or the  Angolan colobus.

There are 6 recognized sub-species (though there is another suspected undescribed subspecies from the Mahale mountains in Tanzania)


      • Sclater’s Angola colobus, C. a. angolensis –Sclater’s Angolan colobus, found in Angola and northward to the great bend in the Congo River
      • Powell-Cotton’s Angola colobus, Friedrichs’s Angolan colobus, Cordier’s Angolan colobus, and Prigogine’s Angolan colobus , in regions of the Democratic Republic of Congo, Rwanda, Uganda, and Tanzania;
      • Ruwenzori colobus C. a. ruwenzorii (Thomas)
      • Cordier’s Angola colobus, C. a. cordieri
      • Prigogine’s Angola colobus, C. a. prigoginei, from Mt. Kabobo
      • Peters Angola colobus or Tanzanian black-and-white colobus, C. a. palliatus -There are 3100-5000 individuals in Kenya 

     

    The Angola colobus occurs in dense rainforests, both in the lowlands and coastal mountains. It lives in most of the Congo Basin, to the south and northeast of the Congo River, as far as Ruwenzori, Burundi and southwestern Uganda. The species can also be found in East Africa, especially in the interior and coastal forests of Kenya and Tanzania and in isolated mountain areas. Although the species is named after Angola, it is quite rare in that country. Of all  species, the Angola colobus occurs in the southernmost latitude. The geographical range lies south of that of the Mantled guereza. It is found up to 2,415 m above sea level in Kenya.

    They are listed as least concern, though estimates for their whole population are hard to come by. Hopefully, I will be able to add more detail in the future

     

     

Black Colobus Monkey

The black colobus (Colobus satanas), or satanic black colobus, is a species of Old World monkey belonging to the genus Colobus. The species is found in a small area of western central Africa. Black colobuses are large, completely covered with black fur, and like all other Colobus monkeys, do not have a thumb. The species has faced large declines in population due to habitat destruction and hunting by humans, and was consequently listed as Vulnerable on the IUCN Red List in 1994.

The black colobus monkey is one of five recognised species in the genus Colobus. The black colobus is the oldest species in this genera and is thought to have diverged 3-4 million years ago.

There are two subspecies of black colobus monkey:

  • Colobus satanas satanas – Bioko black colobus (Waterhouse, 1838)
  • Colobus satanas anthracinus – Gabon black colobus (Le Conte, 1857)

The black colobus monkey is found in Equatorial Guinea, south west Cameroon and central and north-western Gabon. Small populations may also occur in the north of the Republic of the Congo. The subspecies C.s.satanas is only found on Bioko Island, off the coast of Cameroon. The distribution of the black colobus has decreased dramatically – the species is now rare or absent in some areas of its range due to its habitat being destroyed for logging. Black colobuses are known to live at low densities, but there is currently no total population estimate for the species. One of the largest remaining populations of the species, consisting of 50,000-55,900 individuals, is found in Lope Reserve, Gabon. Other remaining large populations are found in the Foret des Abeilles in central Gabon and Douala-Edea Reserve in Cameroon.

The black colobus is an arboreal species that lives high in the canopy of dense rainforest and occasionally coastal sand dune or wooded meadows. Black colobuses are unable to survive in secondary forest that has regrown after a major disturbance such as logging and therefore tend to avoid areas populated by humans. The black colobus cannot be bred in captivity due to the food and habitat it requires.
The black colobus monkey is one of the most threatened primate species in Africa and is currently listed as Vulnerable on the IUCN Red List. This is because the species’ population has declined by over 30% in the past 30 years. The subspecies C.s.satanas is classified as Endangered as its population has declined by over 60% in the last 30 years. The black colobus monkey is now only found in areas which cannot be easily accessed by humans. The species has faced population declines due to logging and illegal hunting for the fur trade which began in the 19th century. Due to improved roads and increased wealth in the area, commercial hunting for the species has become more profitable. 

Today, black colobus monkeys are mainly traded for their meat and account for 20% of the Bushmeat sold in Malabo  One adult black colobus carcass is sold for around US$20.42.The black colobus monkey is listed under Appendix II of CITES, which restricts international trade of the species. The species is also listed under Class B of the “African Convention on the Conservation of Nature and Natural Resources” African Convention on the Conservation of Nature and Natural Resources. Further information and data is needed to in order to help conserve the species. Conservation programs such as the Bioko Biodiversity Protection Program aim to work with local people to learn more about the black colobus monkey and protect it from extinction.

King Colobus Monkey

The king colobus is also known as the western black-and-white colobus and is a species of Old World monkey, found in lowland and mountain rainforests in a region stretching from Senegal, through Guinea-Bissau, Guinea, Sierra Leone and Liberia to the Ivory Coast.

African King colobus monkeys have distinctive long, strong, white tails which act as an extra support as they live mainly up in tall trees of the rainforest canopy and feed on leaves, flowers and fruit. In fact, they spend much of their time eating as leaves have little nutritional value so a great many are needed to fill their quite large stomachs. 

Habitat destruction and the bushmeat trade have reduced the numbers of King colobus and they are now classed as Vulnerable of the IUCN list of endangered species. They are also predated by birds of prey and leopards.

Living up to 30 years, these monkeys produce just one baby a year which is completely white when it’s born – this means it takes a long time for them to recover from reductions in their population. They darken over time until they’re completely black with a white frame to the face and the white tail. 

They are considered Vulnerable with a population that has halved in the last 30 years.

Mantled Guereza

The Mantled Guereza (alsok known as the Guereza colobus monkey, the mantled colobus, eastern black-and-white colobus and the magistrate colobus, is found in a widespread area in central africa. Starting in Nigeria, east and west of the Niger River and the upper Donga River tributaries to the Tabassi District of Cameroon, to Equatorial Guinea, through Chad, Gabon, the Central African republic, republic of Congo into Northern DRC through south Sudan to Ethiopia, Kenya, Uganda Rewanda and southern Tanzania.

The guereza colobus monkey is recognized as the “parent” species to seven “children,” or subspecies. Each of these subspecies occupies a specific range and exhibits slight variations in appearance.

  • Western guereza (C. g. occidentalis) is found from eastern Nigeria, Cameroon, south to Gabon, eastward to southwestern Sudan, and into Uganda, west of the Nile River.
  • Omo River guereza (C. g. guereza) is found in forested areas of the Ethiopian highlands, west of the Rift Valley and within the lowland areas along the Awash River, the Omo River, and in the Blue Nile gorge.
  • Djaffa Mountains guereza (C. g. gallarum), also  known as Neumann’s black-and-white colobus, is found only in the Ethiopian highlands east of the Rift Valley.
  • Dodinga Hills guereza (C. g. dodingae) is found only in the Didinga Hills of southeastern Sudan.
  • Mau Forest guereza (C. g. matschiei) is found in Kenya, west of the Rift Valley, inhabiting forestland within the Rift, west to Mount Elgon (Kenya and Uganda), and south to the Ngorongoro Crater and the Grumeti River in Tanzania.
  • Uarges guereza (C. g. percivali), also known as Percival’s Black-and-White colobus, is found only at Mt. Uarges, the highest peak in the Matthews Range of central Kenya.
  • Kenya guereza (C. g. kikuyuensis) is found in central Kenya, from the Ngong Escarpment, Mt. Kenya, and the Aberdare Mountain Range.

Subspecies classifications for the guereza colobus are still being debated, so it may be some time, before it is understood the exact situation.

They are found in both primary and secondary forests (those that have been disturbed by humans) but appear to prefer disturbed forests. Deciduous and evergreen forests are also used, but only ones which have had time for the trees to create a true canopy.

It is thought to be the “parent” from which the other subspecies came.

They are considered least concern

Ursine Colobus Monkey

The ursine colobus, also known as the white-thighed colobus, Geoffroy’s black-and-white colobus, or the white-thighed black-and-white colobus, is a West African species of primate.

The ursine colobus is quite distinctive, with predominantly black fur and lacking a white mantle. They have a black and naked face which is surrounded by a thick white halo of fur. The ursine colobus is further characterized by white patches on the thighs which vary in width and length. Like other species of colobus, the babies are born with an all white fur coat, which starts to turn black at around three months of age. In contrast to other species of colobus, they have slender bodies and ischial callosities, a hard thickened area of skin on the buttocks that allows comfortable sitting on branches.

Ursine colobus are diurnal and highly arboreal, coming down from trees only occasionally when feeding. Their social behavior is like that of many  polygynous monkeys, with each group consisting of related females their juvenile offspring and a territorial male. The males are highly territorial and disperse upon reaching sexual maturity.Ursine colobus use a roaring call to advertise territory and location, this roar is a low “rur, rur, rur” noise. They also have alarm calls that alert group members when predators have been seen which are a “snorting” sound, made by all members of the group except infants. Ursine colobus are mainly vegetarian and have a diet which is made up of new leaves and seeds, with the occasional addition of fruits, insects, and termite clay.

The ursine colobus is threatened by both hunting and deforestation. Its range falls within a region which includes a dense and rapidly growing human population, where forest destruction has been extensive, and there is uncontrolled hunting of wildlife in many places. However, in some parts of their range these monkeys are held to be sacred. It is listed as Class A under the African Convention, and under Appendix II of CITES. They are known to live within a number of protected areas including Comoe National Park Fazao-Malfakassa National Park and Mole, Bui and Digya National Parks (Ghana).

It is listed as one of the worlds 25 most endangered primates and is critically endangered. It is thought that around 1000 remain in the wild. it is listed as critically endangered because between 1992 and 2019 the population fell by over 80%.

Olive Colobus Monkey

The olive colobus monkey is also also known as the green colobus or Van Beneden’s colobus. Its English name refers to its dull olive upperparts. It is the smallest colobine monkeys and is rarely observed in its natural habitat because of its cryptic coloration and secretive nature. It is found in the rain forests of West Africa, ranging from southern Sierra Leone to Nigeria. The IUCN Red List classifies the olive colobus as vulnerable (previously near threatened), and the change has been caused by habitat loss and hunting. Though much of the land within the range of the olive colobus has been affected by human activities, it retains its ability to thrive in small degraded forest fragments (an advantage, as many other primate species do not do well in this way).

It is a small-bodied mammal with an average body weight of 4.6 kilograms for males and 4.1 kilograms for females. Their coloration allows them to stay camouflaged within the trees reducing the risk of predation. They have large feet for a colobus monkey.

The natural habitat of the olive colobus includes second growth within tall forests, palm forests and swamps, where they feed in the lower and middle vegetation strata. The olive colobus is mainly folivorous (herbivore which specializes in eating leaves), although it may consume fruits and seeds when available. The diet consists primarily of young leaves, and they tend to avoid mature leaf parts altogether. This is related to the fact that it is a forestomach fermenter with a small body size, which requires it to obtain a very high quality diet. The fact that olive colobus monkeys utilize this type of fermentation also relates to their lack of fruit consumption, because fruits that contain high levels of acid can overly lower the pH of the stomach, causing negative and sometimes lethal effects on microorganisms living within it.[8]

The olive colobus monkey is a very cryptic and shy animal, which can make the observation and understanding of its behaviour difficult. What is known about interactions between olive colobus monkeys and other related species shows that their social structure is very complex.

Olive colobus monkeys are found in small groups containing multiple breeding males, several females, and their infants. Though found in groups of only a few individuals, olive colobus monkeys are almost always seen in association with other monkeys, particularly the Diana monkey. There have been many suggestions as to how this relationship benefits the olive colobus, such as reducing the risk of predation. A piece of evidence that gives support to this idea is the willingness of the olive colobus to travel to higher altitudes in the tree tops to feed when other species are nearby.

In addition to serving as a means of predator avoidance, the close association with Diana monkeys is a mechanism used by male olive colobus monkeys to obtain new female mates. The olive colobus mating system is unique in that unlike many species living in small groups, there is no evidence of male monopolization over females. It has been proposed that females use aspects of their reproductive biology(long receptive periods, promiscuous mating, and mating overlap among females) along with mating behaviours to limit the monopolization of males in a group. Benefits to the avoidance of male monopolization include direct or indirect female mate choice, decreasing the risk of infanticide, and increased paternal care for offspring.

As with almost all primate species, the olive colobus monkey is very susceptible to habitat loss due to increased encroachment of hunters and farmers on both protected and unprotected lands. In order to ensure that this threatened species is protected, the olive colobus has been listed under Appendix II of CITES and as a Class A species under the African Convention on the Conservation of Nature and Natural Resources, which monitor the international trade of species and their status in the environment. The olive colobus is also covered in many protected areas including Taï National Park on the Ivory Coast of West Africa, which was declared a Forest and Wildlife Refuge in 1926 and accepted as a biosphere reserve in 1982. The park has a total area of 330,000 hectares, plus a 20,000-hectare buffer zone, where new plantations and settlement are prohibited.

Though efforts have been established in order to protect the olive colobus monkey and its habitat, illegal farming and hunting are still a fundamental threat to this species’ survival. To ensure that the olive colobus will thrive in the future, stricter enforcement of laws and regulations should be implemented, as well as the development of educational and public awareness plans. The olive colobus will also benefit from further study and observation.

Video Gallery of each species above (in the same order as they are listed above

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