Zanzibar red colobus

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Zanzibar red colobus [1]
Piliocolobus kirkii 7.jpg
Adult at Jozani Forest
CITES Appendix I (CITES) [3]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Cercopithecidae
Genus: Piliocolobus
Species:
P. kirkii
Binomial name
Piliocolobus kirkii
(J. E. Gray, 1868)
Procolobus kirkii distribution (2).svg
geographic range
  extant (resident)
  extinct

The Zanzibar red colobus (Piliocolobus kirkii) is a species of red colobus monkey endemic to Unguja, the main island of the Zanzibar Archipelago, off the coast of Tanzania. It is also known as Kirk's red colobus after Sir John Kirk, the British Resident of Zanzibar who first brought it to the attention of zoological science. It is now classified as an endangered species and in the mid-1990s was adopted as the flagship species for conservation in Zanzibar. The population is still decreasing, and conservationists are attempting to work with the local government to devise a proper, effective strategy to protect the population and habitat. Challenges include the species' habitat, which is limited to the archipelago. The species has been reclassified three times; it was previously in the genus Colobus , then in the genus Procolobus , and later in the genus Piliocolobus .

Contents

Evolutionary history and taxonomy

The Zanzibar red colobus, Piliocolobus kirkii, population on Zanzibar, represents a population of red colobus that is believed to have been isolated on the island after sea levels rose toward the end of the Pleistocene epoch. Furthermore, it is suggested through mitochondrial analysis, that phylogenetic groups within the red colobus have been genetically isolated from another since the Pliocene. [4]

Examining cranial morphology has shown that P. kirkii has diverged from mainland Piliocolobus to its own species. It has experienced an acceleration in morphological evolution of size which is suggested to be the result of insularity on the island and environmental pressures such as competition, habitat, predation and/or resource availability. There has been no evidence for population bottlenecks in the species. [5]

The smaller cranium of P. kirkii in contrast to the mainland colobus monkey, is consistent with Foster's rule (also known as the island rule) in which the original (larger) animal becomes smaller over time when there are limited resources. [5] [6] Males tend to have pedomorphic traits which include a shorter face, large orbits and an enlarged neurocranium. It is not certain how long ago and where this evolutionary change occurred.

Through molecular analyses, it is indicated that P. kirkii is more closely related to the Udzungwa red colobus (P. gordonorum) compared to other red colobus species. [7] This analysis has also placed the divergence of P. kirkii from its sister species P. godronorum at about 600,000 years ago, [8] which actually allows for an older evolutionary age compared to the previous assumption that it had become its own species around the last glacial period. The species has been reclassified twice; it was previously in the genus Colobus , and more recently in the genus Procolobus and then the genus Piliocolobus. [1] [9]

An alternative common name is Kirk's red colobus after Sir John Kirk (1832–1922), the British Resident of Zanzibar who first brought it to the attention of zoological science. [10]

Physical description

This Old World monkey's coat ranges from dark red to black, accented with a black stripe along the shoulders and arms, and a pale underside. Its black face is crowned with long, white hair, and features a distinguishing pink mark on its lips and nose. Also, the Zanzibar red colobus has a long tail used only for balancing—it is not prehensile. [11] Sexual dimorphism is generally decreased in the species, meaning the females have little difference in their body size and colour from their male counterparts. [5] Females usually outnumber the males in their groups. The species has a notably small cranium and rotund body shape, with males potentially reaching over 12 kg (26 lb) and females, 10 kg (22 lb). [12] In adults, highly differentiated facial features help them to distinguish each other in a group. [11]

The word "colobus" comes from Greek ekolobóse, meaning "he cut short", and is so named because of the significant reduction in size, or complete lack of an opposable thumb in comparison to other primates. [13] To make up for this, they have four long digits that align to form a strong hook, allowing them to easily grasp branches and climb. [11]

Locals on the island have called the Zanzibar red colobus kima punju which means "poison monkey" in Swahili because of their strong smell unlike other monkeys. This has caused people to hold negative views of the monkey and even to say it has an evil influence on trees on which they feed, ultimately killing the trees. [14]

Habitat

The Zanzibar red colobus is found in three forests of the Zanzibar archipelago. [15] It displays a wide habit tolerance, but it is mainly an arboreal species and prefers drier areas over wet ones. Its habitats include coastal thickets and coastal rag scrub, but it can also be found in agricultural areas and in mangrove swamps; the latter provides food year-round. [15] [16] When found in agricultural areas, the monkey is more used to humans and comes closer to the ground.

About 1,600 to 3,000 individuals remain, [17] and currently, 50% of the monkeys found on the islands live outside protected zones. [15] [18] The largest and most significant area of protection and habitat for the monkey is in Jozani National Park, which provides 25 km2 (9.7 sq mi) of land reserve. [19] It is located on the main island and the populations here have been greatly studied in regards to both their ecology and behavior. Even so, many groups have been found in shambas (Swahili for "farmland") in close proximity to the park. [20] In these shambas adjacent to the park, higher densities of the red colobus have been reported living here in more cohesive groups, compared to inside the park reserve. [20] The incidence of some of these monkeys living permanently outside the zone of the protected park reserve can increase the endangerment of the groups.

At Jozani Forest Red Colobus 7.jpg
At Jozani Forest
A mother and baby ZanzibarColobus.jpg
A mother and baby

Behavior

Males and females share the same coat pattern Red Colobus monkey.jpeg
Males and females share the same coat pattern

The groups consist of up to four adult males and many adult females; typically yielding a 1:2 ratio of males to females. [15] Young of varying ages are also incorporated in the group. The number of monkeys in a group can range from 30 to 50 individuals. The species is a very social animal, and can often be observed playing and grooming during the rest periods between meals. Unlike females, in a group, males actually maintain close bonds, acting together in defense of their group and even in grooming each other. [11]

Feeding

Feeding is also a group activity. It begins to feed in the morning, and is more active during the cooler parts of the day. Loud calls from males indicate the group is ready to move to another tree to feed. This monkey is mainly a foliovore, and on average, half of the leaves consumed are young leaves. [17] They also eat leaf shoots, seeds, flowers, and unripe fruit. It has also been found eating bark, dead wood, and soil. [17] It is one of the few species that do not eat ripe fruits; it has a sacculated stomach with four chambers specific for breaking down plant materials, however it cannot digest the sugars contained in mature fruits. [21] Because the monkey feeds on young leaves (though not limited to them), there are instances where it consumes charcoal, which is believed to aid their digestion of the toxins (possibly phenolic compounds) found in the young leaves of the Indian almond tree and mango tree. [17] The habit of consuming charcoal is thought to be a learned behavior presumably passed on from the mother to her offspring. [17] The presence of charcoal deposits were shown to result in these monkeys being more likely to inhabit areas that had trees as a food source that were rich in phenolics. [22] It has been noted, however, that not all populations on the islands carry out the behavior, but that it is rather mostly done by those who consume more perennial and exotic foliage. [17]

Since some populations use mangroves as a source of food, it is natural for the monkey to consume more sodium chloride (NaCl). Because of this, those populations have been observed to drink water directly from tree-holes, or licking water off of leaves. This innovative behavior shows the adaptation of the monkey to novel ecological and environmental circumstances. [16]

In the dry season, one of the staple foods, Indian almond tree, as previously mentioned, drops its leaves and can cause the monkey to go beyond park boundaries in order to extend its feeding range. This puts the already endangered colobine at more risk. [17]

Reproduction

Males usually reach sexual maturity at about 3–3.5 years old, while females attain it at about two years old. [11] Females approaching estrous can be easily identified because of the swelling and bright red coloration of the genital area. This signals to males that the given female is ready for mating. [11] Moreover, just prior to mating, males will use their fingers to probe the female's birth canal. This is immediately followed by sniffing the area because estrogen and progesterone can be detected by this method, further helping the male conclude if the female is indeed ready to breed. [11]

Gestation is about 6 months for colobus monkeys and one female has about 1–2 new-born every two years. Parental care is intense and often, the role is shared by multiple females of the group. It is observed that about 76% of offspring are born between September and December. [17] Infanticide has also been noted on occasion when a new male joins a given group that has infants. [15]

Research has suggested that the ability for dietary expansion, which consuming charcoal partly allows, explains the higher birth rates and densities due to resource availability. [17] Birth rates for those living in mangroves are higher than colobus monkeys living in coral rag forests. [23]

There are higher birthing rates between October–December for colobines on Uzi Island and then January–February for those in Kiwengwa, located on the eastern side of the main island. [17] Infant mortality can be significantly high with half of the infants born not reaching more than six months of age. [24] The birth rates themselves, however, are actually decreased in comparison to mainland colobus monkeys and interbirth intervals are longer as well. [20] Research has suggested that this is a consequence of disturbed habitats in which mainland colobi are not so affected.

Communication

The red colobus species have a smaller larynx compared to other members of the Colobinae subfamily. The male's call is more of an alto or soprano in contrast to the low bass of a male's in black-and-white colobus species. The Zanzibar red colobus is non-territorial in nature and as so does not typically make loud, territorial threat calls. Zanzibar red colobus distress and warning calls are the "bark", "chist", or "wheet". One of the loudest calls from the monkey is heard when he expresses his dominance over the group and when checking the sexual status of his females. [11]

The call heard most often by people in or near Jozani Forest is the 'alerting signal'. This is an attention-getting call that is derived from the progression call. Chirps and grunts are made when there are changes in the surrounding environment such as changes in weather or animal movement in proximity to the group. With most arboreal animals, there are two different alerting calls, one for when a predator is on land, and another when there is an aerial predator. However, because of the lack of larger birds of prey in Zanzibar, such calls are not often witnessed. The young, on the other hand, because of their smaller size and vulnerability, do at times make such calls when they see shadows. [11]

Because the Zanzibar red colobus is extremely social, it has a specific call for when it is alone for a certain amount of time upon which it feels vulnerable or threatened. The young are typically the ones to make such a call that sounds like a loud scream, but adults are occasionally likely (when deemed necessary) to make some variation of the call as well. [11]

Conservation

A number of factors have contributed to the monkey's endangered status. First, an increase in deforestation has resulted in a significant reduction in resources and habitat; second, it is hunted for meat and pet markets. To counteract the decline in population, various attempts have been made to protect the species. In 1974, specimens were moved to Ngezi Forest on Pemba Island to try to re-establish the monkey's population. [15] It had been found, however, that 20 years after the translocation to the island only one group of Zanzibar red colobus was found and with few sightings and interviews with locals, the population was estimated to be between 15 and 30 individuals. Researchers concluded that the group had certainly survived but did not increase in number possibly due to adverse relations with humans. Some locals in Pemba hold superstitions against the monkey because of the idea that it brings bad luck upon farmers. [15] This may explain the reason that they have not significantly grown in population size.

On Uzi and Vundwe Islands, the Zanzibar red colobus is subject to extensive habitat destruction, particularly with coral rag forests. There is also reported poisoning, netting, and disappearance of monkeys as well as other with animals. [23]

Various attempts have been made for conservation of the species. One project was with the World Wildlife Fund, specifically in Menai Bay which is located just west of Uzi Island. [23] Another funded by the Wildlife Conservation Society designated the Zanzibar red colobus as the flagship species in a long-term study on population, human influence, and behaviour. [25] [26]

The African Convention has played a role in the conservation of the animal by categorizing it as 'Class A.' [27] According to the document African Convention on the Conservation of Nature and Natural Resources, 'Class A' is described as:

species in Class A shall be totally protected throughout the entire territory of the Contracting States; the hunting, killing, capture or collection of specimens shall be permitted only on the authorization in each case of the highest competent authority and only if required in the national interest or for scientific purposes. [27]

It has been suggested that an important way to promote conservation of the monkey is to simply spread awareness about it – that it is not a harmful animal and that it can actually be good for the region's economy because it draws tourism. This has been the case on the island of Unguja (Zanzibar). [15] Furthermore, it would be necessary to establish and designate protected zones.

Related Research Articles

<span class="mw-page-title-main">Black-and-white colobus</span> Genus of Old World monkeys

Black-and-white colobuses are Old World monkeys of the genus Colobus, native to Africa. They are closely related to the red colobus monkeys of genus Piliocolobus. There are five species of this monkey, and at least eight subspecies. They are generally found in high-density forests where they forage on leaves, flowers and fruit. Social groups of colobus are diverse, varying from group to group. Resident-egalitarian and allomothering relationships have been observed among the female population. Complex behaviours have also been observed in this species, including greeting rituals and varying group sleeping patterns. Colobi play a significant role in seed dispersal.

<span class="mw-page-title-main">Old World monkey</span> Family of mammals

Old World monkeys are primates in the family Cercopithecidae. Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons, red colobus and macaques. Common names for other Old World monkeys include the talapoin, guenon, colobus, douc, vervet, gelada, mangabey, langur, mandrill, surili (Presbytis), patas, and proboscis monkey.

<span class="mw-page-title-main">Colobinae</span> Subfamily of Old World monkeys

The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split the colobine monkeys into two tribes, while others split them into three groups. Both classifications put the three African genera Colobus, Piliocolobus, and Procolobus in one group; these genera are distinct in that they have stub thumbs. The various Asian genera are placed into another one or two groups. Analysis of mtDNA confirms the Asian species form two distinct groups, one of langurs and the other of the "odd-nosed" species, but are inconsistent as to the relationships of the gray langurs; some studies suggest that the gray langurs are not closely related to either of these groups, while others place them firmly within the langur group.

<span class="mw-page-title-main">Mantled guereza</span> Species of mammal

The mantled guereza, also known simply as the guereza, the eastern black-and-white colobus, or the Abyssinian black-and-white colobus, is a black-and-white colobus, a type of Old World monkey. It is native to much of west central and east Africa, including Cameroon, Equatorial Guinea, Nigeria, Ethiopia, Kenya, Tanzania, Uganda and Chad. The species consists of several subspecies that differ in appearance. It has a distinctive appearance, which is alluded to in its name; the long white fringes of hair that run along each side of its black trunk are known as a mantle. Its face is framed with white hair and it has a large white tail tuft.

<span class="mw-page-title-main">Red colobus</span> Genus of Old World monkeys

Red colobuses are Old World monkeys of the genus Piliocolobus. It was formerly considered a subgenus within the genus Procolobus, which is now restricted to the olive colobus. They are closely related to the black-and-white colobus monkeys, and some species are often found in groups with the blue monkey. The western red colobus is frequently hunted by the common chimpanzee.

<span class="mw-page-title-main">Miss Waldron's red colobus</span> Species of Old World monkey

Miss Waldron's red colobus is a species of the red colobus native to West Africa. It had previously been described as a subspecies of the western red colobus, P. badius. It has not been officially sighted since 1978 and was considered extinct in 2000. However, new evidence suggests that a very small number of these monkeys may be living in the southeast corner of Côte d'Ivoire. The IUCN Red List notes Miss Waldron's red colobus as critically endangered.

<span class="mw-page-title-main">Western red colobus</span> Species of Old World monkey

The western red colobus, also known as the bay red colobus, rust red colobus or Upper Guinea red colobus, is a species of Old World monkey in West African forests from Senegal to Ghana. All other species of red colobuses have formerly been considered subspecies of P. badius. It is often hunted by the common chimpanzee. In 1994, western red colobus monkeys infected many chimpanzees with Ebola virus when the chimpanzees hunted the monkeys as prey.

<span class="mw-page-title-main">Black colobus</span> Species of Old World monkey

The black colobus, 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.

<span class="mw-page-title-main">Tana River mangabey</span> Species of Old World monkey

The Tana River mangabey is a highly endangered species of primate in the family Cercopithecidae. Some authorities have included the taxa agilis and sanjei as subspecies of this species, while others award these full species status.

<span class="mw-page-title-main">Pennant's colobus</span> Species of Old World monkey

Pennant's colobus or Pennant's red colobus is a species of tree-dwelling primate in the family Cercopithecidae. It is endemic to tropical Central Africa. Three subspecies have traditionally been recognised but its distribution is peculiarly disjunct and has been considered a biogeographical puzzle, with one population on the island of Bioko, a second in the Niger River Delta in southern Nigeria, and a third in east-central Republic of Congo. It is found in rainforests and marshy forests. It is threatened by habitat loss and hunting for bushmeat.

<span class="mw-page-title-main">Tana River red colobus</span> Species of Old World monkey

The Tana River red colobus, also called the eastern red colobus, is a highly endangered species of primate in the family Cercopithecidae. It is endemic to a narrow zone of gallery forest near the Tana River in southeastern Kenya.

<span class="mw-page-title-main">Olive colobus</span> Species of Old World monkey

The olive colobus monkey, also known as the green colobus or Van Beneden's colobus, is a species of primate in the family Cercopithecidae. Its English name refers to its dull olive upperparts. It is the smallest example of all 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, with the cause of its decline attributed to 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.

<span class="mw-page-title-main">Ugandan red colobus</span> Species of Old World monkey

The Ugandan red colobus or ashy red colobus is an endangered species of red colobus monkey, recognised as a distinct species since 2001. There is disagreement however over taxonomy with many considering the Ugandan red colobus to be a subspecies. The Ugandan red colobus is an Old World monkey which is found in five different locations across Uganda and Tanzania.

<span class="mw-page-title-main">Jozani Chwaka Bay National Park</span> National park in Tanzania

The Jozani Chwaka Bay National Park is a 50 km2 (19 sq mi) national park in Tanzania located on the island of Zanzibar. It is the only national park in Zanzibar.

<span class="mw-page-title-main">Niger Delta red colobus</span> Species of Old World monkey

The Niger Delta red colobus is a critically endangered species of colobus monkey endemic to the western part of the Niger Delta. It is threatened by hunting and habitat loss.

<span class="mw-page-title-main">Wildlife of Zanzibar</span>

The wildlife of Zanzibar consists of terrestrial and marine flora and fauna in the archipelago of Zanzibar, an autonomous region of Tanzania. Its floral vegetation is categorized among the coastal forests of eastern Africa as the Southern Zanzibar-Inhambane coastal forest mosaic and the Northern Zanzibar-Inhambane coastal forest mosaic. Its faunal species are mostly small animals, birds, and butterflies.

<span class="mw-page-title-main">Bouvier's red colobus</span> Species of Old World monkey

Bouvier's red colobus is a species of colobus monkey rediscovered in the Republic of the Congo in 2015, after four decades without a confirmed sighting.

Colin A. Chapman is a professor at the Vancouver Island University in British Columbia, Canada. In addition, he is a Fellow of the Royal Society of Canada, an Honorary Lecturer at Makerere University in Uganda, a Member of the Committee of Research and Exploration at National Geographic, and an Associate Scientists of the Wildlife Conservation Society in New York. Prior to taking on his position at McGill University, he was at the University of Florida in the Department of Zoology from 1993 to 2004. He is internationally recognized for his 30+ years of research into primate ecology, population regulation, nutrition, and disease dynamics and for his contribution to conservation globally.

<span class="mw-page-title-main">Lang's red colobus</span> Species of Old World monkey

Lang's red colobus is a species of red colobus monkey. Historically it had been treated as a subspecies of the Central African red colobus, but more recent taxonomies generally treat it as a separate species.

References

  1. 1 2 Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 169–170. ISBN   0-801-88221-4. OCLC   62265494.
  2. ↑ Davenport, T. (2019). "Piliocolobus kirkii". IUCN Red List of Threatened Species . 2019: e.T39992A168568335. doi: 10.2305/IUCN.UK.2019-3.RLTS.T39992A168568335.en . Retrieved 19 November 2021.
  3. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  4. ↑ Cardini A, Elton S (2009). "The radiation of red colobus monkeys (Primates, Colobinae): morphological evolution in a clade of endangered African primates". Zoological Journal of the Linnean Society. 157: 197–224. doi: 10.1111/j.1096-3642.2009.00508.x .
  5. 1 2 3 Nowak K, Cardini A, Elton S (2008). "Evolutionary Acceleration and Divergence in Procolobus kirkii". International Journal of Primatology. 29 (5): 1313–1339. doi:10.1007/s10764-008-9306-1. S2CID   24435346.
  6. ↑ Whittaker RJ (1998). Island biogeography: ecology, evolution, and conservation. Oxford University Press. pp. 73–75. ISBN   9780198500209.
  7. ↑ Ting, N.; Delson, E.; Oates, J. F. & Disotell, T. R (2006). Molecular systematics of red colobus monkeys (Procolobus [Piliocolobus]). Vol. 27. pp. Abstract 96. ISBN   978-0549592365.{{cite book}}: |journal= ignored (help)
  8. ↑ Ting, N (2008). "Mitochondrial relationships and divergence dates of the African colobines: evidence of Miocene origins for the living colobus monkeys". Journal of Human Evolution. 55 (2): 1–14. doi:10.1016/j.jhevol.2008.02.011. PMID   18423802.
  9. ↑ Mittermeier, Russell A.; Rylands, Anthony B.; Wilson, Don E., eds. (2012). Handbook of the Mammals of the World: Volume 3, Primates. Lynx. pp. 705–712. ISBN   978-8496553897.
  10. ↑ Inventory Acc.942 Papers of Sir John Kirk GCMB KCB and Lady Kirk née Helen Cooke. National Library of Scotland: Manuscripts Division.
  11. 1 2 3 4 5 6 7 8 9 10 Jorgensen, Matthew. (2009). "Behavioral Application in Wildlife Photography: Developing a Foundation in Ecological and Behavioral Characteristics of the Zanzibar red colobus Monkey (Procolobus kirkii) as it Applies to the Development Exhibition Photography". SIT – Zanzibar Coastal Ecology and Natural Resource Management.
  12. ↑ Kingdon, J (1974). East African Mammals – Vol I: Primates. Academic Press.
  13. ↑ Colobus Monkey. American Wildlife Foundation.
  14. ↑ McIntyre, C.; Shand, Susan (2009). Zanzibar: Pemba · Mafia: 7th Edition. Guilford, CT: Bradt Travel Guides Ltd., Inc. p. 53. ISBN   978-1-84162-254-5.
  15. 1 2 3 4 5 6 7 8 Ciani, Camperio A; et al. (2001). "Survival of a small translocated Procolobus kirkii population on Pemba Island". Animal Biodiversity and Conservation. 24 (1).
  16. 1 2 Nowak, K. (2008). "Frequent Water Drinking by Zanzibar Red Colobus (Procolobus kirkii) in a Mangrove Forest Refuge". American Journal of Primatology. 70 (11): 1081–1092. doi:10.1002/ajp.20605. PMID   18651613. S2CID   27755894.
  17. 1 2 3 4 5 6 7 8 9 10 Nowak K. (2007). "Behavioral flexibility and demography of Procolobus kirkii across floristic and disturbance gradients: Dissertation for the Degree of Doctor of Philosophy." Department of Biological Anthropology, University of Cambridge.
  18. ↑ Siex KS, Struhsaker TT (1999). "Colobus monkeys and coconuts: a study of perceived human-wildlife conflicts". Journal of Applied Ecology. 36 (6): 1009–1020. doi: 10.1046/j.1365-2664.1999.00455.x . S2CID   84472733.
  19. ↑ Forestry Technical Paper Number 45, Department of Commercial Crops Fruits & Forestry (DCCFF), Tanzania (2006), p. 2
  20. 1 2 3 Siex KS, Struhsaker TT (1999). "Ecology of the Zanzibar red colobus monkey: demographic variability and habitat stability". International Journal of Primatology. 20 (2): 163–192. doi:10.1023/A:1020558702199. S2CID   23228971.
  21. ↑ Ankel-Simons F (2000). Primate Anatomy (Second ed.). San Diego: Academic Press. pp. 113–114. ISBN   978-0-12-058670-7.
  22. ↑ Struhsaker, T. T.; Cooney, D. O.; Siex, K. S. (1997). "Charcoal consumption by Zanzibar red colobus monkeys: Its function and its ecological and demographic consequences". International Journal of Primatology. 18 (1): 61–72. doi:10.1023/a:1026341207045. S2CID   25002260.
  23. 1 2 3 Nowak K, Perkin A, Jones T. (2009) Update on habitat loss and conservation status of the endangered Zanzibar red colobus on Uzi and Vundwe Islands. Unpublished report for Department of Commercial Crops, Fruits and Forestry, Zanzibar.
  24. ↑ Silkiluwasha F (1981). "The distribution and conservation status of the Zanzibar red colobus". African Journal of Ecology. 19 (1–2): 187–194. doi:10.1111/j.1365-2028.1981.tb00662.x.
  25. ↑ "Zanzibar red colobus". Tanzania Program. Wildlife Conservation Society. 2016. Retrieved 29 September 2016.
  26. ↑ "Research". Zanzibar Red Colobus Project. Retrieved 29 September 2021.
  27. 1 2 African Convention on the Conservation of Nature and Natural Resources Archived 2010-12-05 at the Wayback Machine , Organisation of African Unity, p. 15.

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