Bay duiker

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Bay duiker
Cephalophus dorsalis.JPG
Individual in Gabon
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Genus: Cephalophus
Species:
C. dorsalis
Binomial name
Cephalophus dorsalis
J. E. Gray, 1846
Subspecies
  • C. d. dorsalis(Gray, 1846)
  • C. d. castaneus(Thomas, 1892)

The bay duiker (Cephalophus dorsalis), also known as the black-striped duiker and the black-backed duiker, is a forest-dwelling duiker native to western and southern Africa. It was first described by British zoologist John Edward Gray in 1846. Two subspecies are identified. The bay duiker is reddish-brown and has a moderate size. Both sexes reach 44–49 cm (17–19 in) at the shoulder. The sexes do not vary considerably in their weights, either; the typical weight range for this duiker is 18–23 kg (40–51 lb). Both sexes have a pair of spiky horns, measuring 5–8 cm (2.0–3.1 in). A notable feature of this duiker is the well-pronounced solid stripe of black extending from the back of the head to the tail.

Contents

The bay duiker is a nocturnal animal. It tends to remain solitary, but pairs can also be observed. The leopard is the main predator of this duiker. It mainly prefers fruits, but may also feed on animal matter such as bird eggs. Females may conceive by the age of 18 months. Breeding occurs throughout the year. Gestation lasts about 240 days, following which generally a single offspring is born. The lifespan of the bay duiker is typically 17 to 18 years.

The bay duiker prefers old-growth or primary forests. It has been historically overhunted across its range for bushmeat. The survival of the bay duiker is also threatened by human settlement and agricultural expansion due to this duiker's preference for old-growth forests, and habitat degradation. The bay duiker is, however, still a common duiker species, and is classified as near threatened by the International Union for Conservation of Nature and Natural Resources.

Taxonomy and etymology

Common duiker

Abbott's duiker

Yellow-backed duiker

Jentink's duiker

Bay duiker

Zebra duiker

Phylogenetic relationships of the bay duiker (Johnston et.al. 2012)

The bay duiker was first described by British zoologist John Edward Gray in 1846. [3] The generic name probably comes from the combination of the New Latin word cephal, meaning head, and the Greek word lophos, meaning crest. [4] The specific name dorsalis is a Latin word referring to the back surface of an object. [5] The common name "duiker" comes from the Afrikaans word duik, or Dutch dūken (both mean "diver") [6] owing to the tendency of this antelope to seek cover in bushes. [7] The bay duiker is also known as the black-striped duiker and the black-backed duiker. [8]

A 2001 phylogenetic study divided Cephalophus into three distinct lineages: the giant duikers, east African red duikers and west African red duikers. The bay duiker was classified as a giant duiker along with the yellow-backed duiker (C. silvicultor), Abbott's duiker (C. spadix), and Jentink's duiker (C. jentinki). [9] In 2012, Anne R. Johnston (of the University of Orleans) and colleagues constructed a cladogram of the subfamily Cephalophinae (duiker) based on mitochondrial analysis. They showed that within the "giant duiker" group, the bay duiker formed a clade with Jentink's duiker, and the zebra duiker is sister to this clade. Similarly, Abbott's duiker and the yellow-backed duiker form a clade sister to Sylvicapra . The bay duiker and Jentink's duiker probably evolved during the Pleistocene, less than 2.5 million years ago. [10]

Although the species may be monotypic, a 2003 paper identified two subspecies of the bay duiker: [11] [12]

Description

An illustration of the bay duiker from The Book of Antelopes (1894) by Philip Sclater The book of antelopes (1894) Cephalophus dorsalis.png
An illustration of the bay duiker from The Book of Antelopes (1894) by Philip Sclater

The bay duiker is a moderately sized antelope; the typical head-and-body length is 76–103 centimetres (30–41 in). [8] Both sexes reach 44–49 centimetres (17–19 in) at the shoulder. The sexes do not vary considerably in their weights either; the typical weight range for this duiker is 18–23 kilograms (40–51 lb). [13] Hence, sexual dimorphism in this species is not as remarkable as in other bovids, though females are often larger than males. [8] The tail, black on the outside but white in the inner parts, is 9–11 centimetres (3.5–4.3 in) long. [13] The tail of the eastern bay duiker terminates in a white tuft. [8] Both sexes possess a pair of spiky horns, measuring 5–8 centimetres (2.0–3.1 in). Rowland Ward, however, recorded a maximum horn length of 12.3 centimetres (4.8 in) from Yokadouma (Cameroon). [13] The horns of females are generally narrower. [8]

Both sexes have a bright reddish-brown coat. The ventral parts and the flanks are all reddish-brown, and the legs dark brown. A notable feature of this duiker is the well-pronounced solid stripe of black extending from the back of the head to the tail. This stripe is narrower in females. [8] Due to its nocturnal nature, the bay duiker has large conspicuous eyes. Whiskers can be observed above the eyes and around the nostrils. The patches of white fur around the whiskers are in sharp contrast to the dark reddish face. [13] Juveniles have a dark coat, that develops the stripes and chestnut to reddish-brown color gradually. The face is marked by a dark region from the nose to the forehead, separated from the rest of the face by two light brown furrows extending above or circling its eyes. Above the eyes and on the lips and chin white spots can be seen. The head has a diminutive crest (a tuft of hair), and is dark brown. [8] The eastern bay duiker is larger and heavier than the western bay duiker, with larger ears and darker coloration. The dorsal stripe is wider and lighter in color in the eastern bay duiker. [8]

The bay duiker is similar to several other duikers. The red duiker can not be readily distinguished from the bay duiker. Though Ogilby's duiker resembles the bay duiker in size and pelage color, the ventral side is paler and the dorsal stripe starts from the shoulders instead of the back of the head. [8] Additionally, the body posture and horn characteristics of the two species differ to a large extent. [14] The bay duiker, as well as the Ogilby's duiker, are remarkably similar to the black duiker, except for the pelage coloration. [15] The dorsal stripe of Peters's duiker also begins at the shoulders but widens to cover the whole of the rump, as does the fainter stripe on the white-bellied duiker. The bay duiker can be easily told apart from the black-fronted duiker and Weyns's duiker, that lack stripes. [8]

Ecology and behavior

The African oil palm, one of the trees whose fruits the bay duiker feeds on Elaeis guineensis0.jpg
The African oil palm, one of the trees whose fruits the bay duiker feeds on

The bay duiker is a nocturnal animal, and consequently little is known of its behavioral patterns. During the day, the bay duiker rests against trees or in thickets. It tends to remain solitary, but pairs can also be observed. The bay duiker exhibits remarkable alertness. It depends heavily on its sense of smell for foraging and detecting potential danger. Individuals communicate through preorbital gland secretions and excrement. The leopard is the main predator of this duiker. [8] [13] Eagles, [7] bonobos and mandrills [16] may also prey on the bay duiker. An alarmed individual becomes motionless, and might leap to flee. [8]

Diet

The bay duiker mainly prefers fruits. It feeds on the large fruits of Irvingia species (wild mango), Detarium macrocarpum and the spherical fruits of Mammea africana . Other fruits the duiker may eat are those of Ricinodendron heudelotii and oil-palms, the orange ones of Chrysophyllum beguei , the olive-like ones of Pseudospondias longifolia , the green plums of Panda oleosa and those of Cola rostrata , that resemble cocoa pods. The bay duiker extracts the pulp from the seeds, making a grating sound. If the seeds are large, the duiker spits them out. Smaller seeds such as those of Antrocaryon species may be ingested. [13] A 1989 study found that the soft seeds of plants such as Drypetes gossweileri , Staudtia gabonensis , Dacryoides buettneri , Ongokea gore , Santiria trimera , Annonidium mannii and Pentaclethra macrophylla are preferred. [17] There have been reports of the bay duiker preying on birds (without feeding on the legs and wings) and the embryo of unhatched eggs, carrion, remains of African porcupines and kusimanses, termites, beetles and ants. [7] [13] Dog food may serve as supplement for captive individuals. [18]

Reproduction

Females may conceive by the age of eighteen months. Breeding occurs throughout the year, and no clear peaks are known. [13] A study in Gabon recorded birth peaks before or during maximum abundance of fruits. [19] In central Africa, births peak in January and February. [8] Oestrus lasts for just eighteen hours. [13] The rutting male pursues a female in oestrus continuously. The male might be humming and may move its foreleg outward. If receptive, the female will allow the male to mount by shifting her tail to a side. [13]

Gestation lasts for about 240 days, following which generally a single offspring is born. The infant weighs nearly 1,600–1,690 grams (56–60 oz), and its coat is dark reddish-brown. The brighter reddish-brown to chestnut color develops by five to six months. For the first few weeks after its birth, the infant is kept concealed in dense vegetation when the mother is away. The offspring can start taking solid food within a few weeks. Weaning occurs at around three-and-a-half months. The lifespan of the bay duiker averages 17 to 18 years. [8] [13]

Habitat and distribution

The bay duiker prefers old-growth or primary forests. [14] Home ranges of females are around 0.2–0.4 square kilometres (0.077–0.154 sq mi) large, and those of males are twice the size of those of females. [8] This duiker formerly occurred in the lowland forested areas (warm, moist rainforests) of Guinea. Nowadays, the bay duiker can be found in moist forested islands and riparian forests in the savannas of Guinea and northeastern Sudan. [14] The bay duiker is native to several countries in western and southern Africa: Angola, Cameroon, Central African Republic, The Democratic Republic of the Congo, Côte d'Ivoire, Equatorial Guinea, Gabon, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Sierra Leone and Togo. It is feared to be extinct in Uganda. [1]

Threats and conservation

1869 illustration by Joseph Smit Bay duiker.jpg
1869 illustration by Joseph Smit

The bay duiker has been historically overhunted across its range for bushmeat. A 2007 study of the extinction of the bay duiker in the Ipassa Makokou Biosphere Reserve (Gabon) held overhunting responsible for the elimination of the species from the reserve. [20] The survival of the bay duiker is also threatened by human settlement and agricultural expansion due to this duiker's preference for old-growth forests, and habitat degradation. [1] [14]

The habitat of the bay duiker has depleted to a large extent due to deforestation. [14] The bay duiker, unlike the other duiker species, is still found in significant numbers, [14] and is classified as Near Threatened by the International Union for Conservation of Nature and Natural Resources (IUCN). [1] The Convention on International Trade in Endangered Species (CITES) enlists the species in Appendix II. [3] In 1999, Rod East of the IUCN SSC Antelope Specialist Group estimated the total population at 725,000. [1] The most significant population occurs only in the Taï National Park (Côte d'Ivoire). [14] Protected areas where bay duikers occur include: Sapo National Park (Liberia); Kakum National Park (Ghana); Campo Ma'an National Park, Dja Faunal Reserve and Lobéké National Park (Cameroon); Dzanga-Sangha Special Reserve and Bangassou (Central African Republic); Monte Alén National Park (Equatorial Guinea); Lopé National Park and Minkébé National Park (Gabon); Odzala National Park and Nouabalé-Ndoki National Park (Congo-Brazzaville); Ituri Rainforest, Kahuzi-Biéga, Maiko and Salonga National Parks (Congo-Kinshasa). [1]

Related Research Articles

<span class="mw-page-title-main">Antelope</span> Term referring to an even-toed ruminant

The term antelope is used to refer to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do not form a monophyletic group, as some antelopes are more closely related to other bovid groups, like bovines, goats, and sheep, than to other antelopes.

<span class="mw-page-title-main">Duiker</span> Subfamily of antelopes

A duiker is a small to medium-sized brown antelope native to sub-Saharan Africa, found in heavily wooded areas. The 22 extant species, including three sometimes considered to be subspecies of the other species, form the subfamily Cephalophinae or the tribe Cephalophini.

<span class="mw-page-title-main">Royal antelope</span> Species of mammal

The royal antelope is a West African antelope recognized as the world's smallest. It was first described by Swedish zoologist Carl Linnaeus in 1758. It stands up to merely 25 cm (10 in) at the shoulder and weighs 2.5–3 kg (5.5–6.6 lb). A characteristic feature is the long and slender legs, with the hindlegs twice as long as the forelegs. Horns are possessed only by males; the short, smooth, spiky horns measure 2.5–3 cm (0.98–1.18 in) and bend backward. The soft coat is reddish to golden brown, in sharp contrast with the white ventral parts. In comparison to Bates's pygmy antelope, the royal antelope has a longer muzzle, broader lips, a smaller mouth and smaller cheek muscles.

<span class="mw-page-title-main">Abbott's duiker</span> Species of mammal

Abbott's duiker, also known as minde in Swahili, is a large, forest-dwelling duiker found only in a few scattered enclaves in Tanzania. It may be a subspecies of the yellow-backed duiker. It is very rare, and the first photograph of an Abbott's duiker in the wild was taken as recently as 2003.

<span class="mw-page-title-main">Blue duiker</span> Species of mammal

The blue duiker is a small antelope found in central, southern and eastern Africa. It is the smallest species of duiker. The species was first described by Swedish naturalist Carl Peter Thunberg in 1789. 12 subspecies are identified. The blue duiker reaches 32–41 centimetres (13–16 in) at the shoulder and weighs 3.5–9 kilograms (7.7–19.8 lb). Sexually dimorphic, the females are slightly larger than the males. The dark tail measures slightly above 10 centimetres (3.9 in). It has short, spiky horns, around 5 centimetres (2.0 in) long and hidden in hair tufts. The subspecies show a great degree of variation in their colouration. The blue duiker bears a significant resemblance to Maxwell's duiker.

<span class="mw-page-title-main">Jentink's duiker</span> Species of mammal

Jentink's duiker, also known as gidi-gidi in Krio and kaikulowulei in Mende, is a forest-dwelling duiker found in the southern parts of Liberia, southwestern Côte d'Ivoire, and scattered enclaves in Sierra Leone. It is named in honor of Fredericus Anna Jentink.

<span class="mw-page-title-main">White-bellied duiker</span> Species of mammal

The white-bellied duiker is a duiker found in central Africa. Little is known on the ecology of the species, and only some information on habitat and diet is available.

<span class="mw-page-title-main">Black-fronted duiker</span> Species of mammal

The black-fronted duiker is a small antelope found in central and west-central Africa.

<span class="mw-page-title-main">Maxwell's duiker</span> Species of mammal

The Maxwell's duiker is a small antelope found in western Africa.

<span class="mw-page-title-main">Red-flanked duiker</span> Species of mammal

The red-flanked duiker is a species of small antelope found in western and central Africa in countries as far apart as Senegal and Sudan. Red-flanked duikers grow to almost 15 in (35 cm) in height and weigh up to 31 lb (14 kg). They have russet coats, with greyish-black legs and backs, and white underbellies. They feed on leaves, fallen fruits, seeds and flowers, and sometimes twigs and shoots. The adults are territorial, living in savannah and lightly wooded habitats, and the females usually produce a single offspring each year. They have lifespans of ten to fifteen years in captivity.

<span class="mw-page-title-main">Zebra duiker</span> Species of mammal

The zebra duiker is a small antelope found primarily in Liberia, as well as the Ivory Coast, Sierra Leone, and occasionally Guinea. They are sometimes referred to as the banded duiker or striped-back duiker. It is believed to be one of the earliest duiker species to have evolved.

<span class="mw-page-title-main">Yellow-backed duiker</span> Species of antelope

The yellow-backed duiker is a shy, forest-dwelling antelope of the order Artiodactyla, from the family Bovidae. Yellow-backed duikers are the most widely-distributed of all duikers. They are found mainly in Central and Western Africa, ranging from Senegal and Gambia on the western coast, through to the Democratic Republic of the Congo to western Uganda; their distribution continues southward into Rwanda, Burundi, and most of Zambia.

<span class="mw-page-title-main">Red forest duiker</span> Species of mammal

The red forest duiker, Natal duiker, or Natal red duiker is a small antelope found in central to southern Africa. It is one of 22 extant species form the subfamily Cephalophinae. While the red forest duiker is very similar to the common duiker, it is smaller in size and has a distinguishing reddish coloring. Additionally, the red forest duiker favors a denser bush habitat than the common duiker. The Natal red duiker is more diurnal and less secretive than most forest duikers, so therefore it is easier for them to be observed. In 1999, red forest duikers had an estimated wild population of 42,000 individuals.

<i>Cephalophus</i> Genus of mammals

Cephalophus is a mammal genus which contains at least fifteen species of duiker, a type of small antelope.

<span class="mw-page-title-main">White-legged duiker</span> Species of mammal

The white-legged duiker is a medium-sized antelope species from the subfamily of duikers (Cephalophinae) within the family of bovids (Bovidae). It is native to Gabon and the Republic of the Congo. It was described as subspecies of the Ogilby's duiker by Peter Grubb in 1978. After a revision of the ungulates in 2011 by Colin Groves, it is now regarded as distinct species.

References

  1. 1 2 3 4 5 6 IUCN SSC Antelope Specialist Group (2020). "Cephalophus dorsalis". IUCN Red List of Threatened Species . 2020: e.T4139A166523704. doi: 10.2305/IUCN.UK.2020-1.RLTS.T4139A166523704.en . Retrieved 13 November 2021.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 Wilson, D. E.; Reeder, D. M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 713. ISBN   978-0-8018-8221-0. OCLC   62265494.
  4. ↑ "Cephalophus". Merriam-Webster.com Dictionary . Retrieved 11 February 2016.
  5. ↑ "dorsalis". Cambridge Dictionaries Online. Cambridge University Press. Retrieved 11 February 2016.
  6. ↑ "Duiker". Merriam-Webster.com Dictionary . Retrieved 17 February 2016.
  7. 1 2 3 "Duiker". African Wildlife Foundation . Retrieved 7 March 2016.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Castelló, J.R. (2016). Bovids of the World: Antelopes, Gazelles, Cattle, Goats, Sheep, and Relatives. Princeton University Press. pp. 284–7. ISBN   9780691167176.
  9. ↑ van Vuuren, B.J.; Robinson, T.J. (2001). "Retrieval of four adaptive lineages in duiker antelope: evidence from mitochondrial DNA sequences and fluorescence in situ hybridization". Molecular Phylogenetics and Evolution. 20 (3): 409–25. doi:10.1006/mpev.2001.0962. PMID   11527467.
  10. ↑ Johnston, A.R; Anthony, N.M (2012). "A multi-locus species phylogeny of African forest duikers in the subfamily Cephalophinae: evidence for a recent radiation in the Pleistocene". BMC Evolutionary Biology. 12 (120): x–x. doi: 10.1186/1471-2148-12-120 . PMC   3523051 . PMID   22823504.
  11. ↑ "Cephalophus dorsalis". Integrated Taxonomic Information System . Retrieved 11 February 2016.
  12. ↑ Cotterill, F.P.D. (2003). "Ecology and conservation of small antelope: proceedings of an international symposium on duiker and dwarf antelope in Africa": 59–118.{{cite journal}}: Cite journal requires |journal= (help)
  13. 1 2 3 4 5 6 7 8 9 10 11 J., Kingdon (2013). Mammals of Africa. London: Bloomsbury. pp. 294–8. ISBN   9781408122570.
  14. 1 2 3 4 5 6 7 East, R. (1990). Antelopes : Global Survey and Regional Action Plans. Gland: IUCN. p. 58. ISBN   2-8317-0016-7.
  15. ↑ Robinson, P.T.; Dop, H. (2013). Travel sketches from Liberia Johann Buttikofer's 19th century Rainforest Explorations in West Africa (Annotated English ed.). Leiden: Brill. p. 733. ISBN   9789004236301.
  16. ↑ Kudo, H.; Mitani, M. (April 1985). "New record of predatory behavior by the mandrill in Cameroon". Primates. 26 (2): 161–7. doi:10.1007/BF02382015. S2CID   20928597.
  17. ↑ Feer, F. (1989). "Comparaison des régimes alimentaires de Cephalophus callipygus et C. dorsalis, Bovidés sympatriques de la fôret sempervirente africaine". Mammalia. 53 (4): 563–604. doi:10.1515/mamm.1989.53.4.563. S2CID   85044303.
  18. ↑ Burton, M.; Burton, R. (2002). International Wildlife Encyclopedia (3rd ed.). New York: Marshall Cavendish. p. 728. ISBN   9780761472667.
  19. ↑ Dubost, G.; Feer, F. (1992). "Saisons de reproduction des petits Ruminants dans le nord-est du Gabon, en fonction des variations des ressources alimentaires". Mammalia. 56 (1): 25–44. doi:10.1515/mamm.1992.56.1.25. ISSN   1864-1547. S2CID   84815512.
  20. ↑ van Vliet, N.; Nasi, R.; Emmons, L.; Feer, F.; Mbazza, P.; Bourgarel, M. (September 2007). "Evidence for the local depletion of bay duiker Cephalophus dorsalis, within the Ipassa Man and Biosphere Reserve, north-east Gabon". African Journal of Ecology. 45 (3): 440–3. doi: 10.1111/j.1365-2028.2007.00783.x .
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