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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.
The three disputed species in Cephalophus are Brooke's duiker ( C. brookei), Ruwenzori duiker ( C. rubidis), and the white-legged duiker ( C. crusalbum). Considered to be a subspecies of Ogilby's duiker ( C. nigrifrons), Brooke's duiker was elevated to species status by British ecologist Peter Grubb in 1998. Its status as a species was further seconded in a 2002 publication by Grubb and colleague Colin Groves. However, zoologists such as Jonathan Kingdon continue to treat it as a subspecies. The Ruwenzori duiker is generally considered to be a subspecies of the black-fronted duiker ( C. nigrifrons). However, significant differences from another race of the same species, C. n. kivuensis, with which it is sympatric on the Ruwenzori mountain range, led Kingdon to suggest that it might be a different species altogether. (2025). 9780691164533, Princeton University Press. ISBN 9780691164533 Grubb treated the white-legged duiker as a subspecies of Ogilby's duiker in 1978, but regarded as an independent species by him and Groves after a revision in 2011. (2025). 9781421400938, Johns Hopkins University Press. ISBN 9781421400938 This was supported by a 2003 study.
A 2001 phylogenetic study divided Cephalophus into three distinct lineages - the giant duikers, east African red duikers, and west African red duikers. Abbott's duiker ( C. spadix), the bay duiker ( C. dorsalis), Jentink's duiker ( C. jentinki) and the yellow-backed duiker ( C. silvicultor) were classified as the giant duikers. The east African red duikers include the black-fronted duiker ( C. nigrifrons), Harvey's duiker ( C. harveyi), red-flanked duiker ( C. rufilatus), red forest duiker ( C. natalensis), Ruwenzori duiker, and white-bellied duiker ( C. leucogaster). The third group, the west African red duikers, comprises the black duiker ( C. niger), Ogilby's duiker, Peters' duiker ( C. callipygus), and Weyns's duiker ( C. weynsi). However, the status of two species, Aders's duiker and zebra duiker, remained dubious.
In 2012, Anne R. Johnston (of the University of Orleans) and colleagues constructed a cladogram of the subfamily Cephalophinae (duiker) based on analysis.
Because of their rarity and interspersed population, not much is known about duikers; thus, further generalizations are widely based on the most commonly studied red forest, blue duiker, yellow-backed, and common duiker. In tropical rainforest zones of Africa, people nonselectively hunt duikers for their hide, meat, and horns at highly unsustainable rates.Newing 2001. Population trends for all species of duikers, excluding the common duiker and the smallest blue duiker, are significantly decreasing; Aders' and particularly the larger duiker species such as the Jentink's and Abbott's duikers, are now considered endangered by the IUCN Red List of Threatened Species.IUCN Red List.
Besides reproduction, duikers behave in highly independent manner and prefer to act alone. This may, in part, explain the limited sexual size dimorphism shown by most duiker species, excluding the common duiker, in which the females are distinctly larger than the males.Lunt 2011.
Also, body size is proportional to the amount of food intake and the size of food. Anatomical features such as the head and neck shape also limit the amount and size of food intake. “Anatomical variations... impose further constraints on ingestion” causing differences in the food sources among different species of duiker.
Due to their relative size and reserved nature, duikers' primary defense mechanism is to hide from . Duikers are known for their extreme shyness, freezing at the slightest sign of a threat and diving into the nearest bush. Duikers' social behavior involves maintaining sufficient distance between individuals. However, in contrast to their conserved nature, duikers are more aggressive when dealing with territories; they mark their territory and their mates with secretions from their preorbital glands and fight other duikers that challenge their authorities.Keymer 1969. Male common duikers, especially the younger males, mark their territories also by defecation.
For those duikers that travel alone, they choose to interact with other duikers once or twice a year, solely for the purpose of mating. Although duikers occasionally form temporary groups to gather fallen fruit, because so little is known about how they interact and affect one another, determining which factors contribute the most to their endangerment is difficult.
Duikers prefer to live alone or as pairs to avoid the competition that comes from living in a large group. They have also evolved to become highly selective feeders, feeding only on specific parts of plants. In fact, in his study regarding the relationship between group size and feeding style, P.J. Jarman found that the more selective an organism's diet is, the more dispersed its food will be, and consequently, the smaller the group becomes.
The smaller species, for example the blue duiker, generally tend to eat various seeds, while larger ones tend to feast more on larger fruits. Since blue duikers are very small, they are more efficient in digesting small, high-quality items. Receiving most of their water from the foods they eat, duikers do not rely on drinking water and can be found in waterless areas.Lydekker 1926.
Also, a correlation exists between body size and diet. Larger animals have more robust digestion, stronger jaws, and wider necks, which allow them to consume lower-quality foods and larger fruits and seeds.
Similarly, bay and Peters' duikers can coexist because of their different sleep patterns. This allows Peters' duikers to eat fruits by day, and the bay duikers to eat what is left by night. In consequence of such a life pattern, the bay duiker's digestive system has evolved to consume remaining, rather poor-quality foods.
Another critical influence that duikers have on the environment is acting as “seed dispersers for some plants”.Redford 1992.Wilkie 1998. They maintain a mutualistic relationship with certain plants; the plants serve as a nutritious and abundant food source for the duikers, and simultaneously benefit from the extensive dispersal of their seeds by the duikers.
Overexploitation of duikers affects their population and organisms that rely on them for survival. For instance, plants that depend on duikers for seed dispersal may lose their primary method of reproduction, and other organisms that depend on these particular plants as their resources would also have their major source of food reduced.
Duikers are often captured for bushmeat. In fact, duikers are one of the most hunted animals both in terms of number and biomass in Central Africa.Muchall 1999. For example, in areas near the African rainforests, because people do not raise their own livestock, many people of all classes rely on bushmeat as their source of proteinAnadu 1988. For these people, if the trend of overexploitation continues at such a high rate, the effects of the population decrease in duikers will be too severe for these organisms to serve as a reliable food source.
In addition to the unnaturally high demand for bushmeat, unenforced hunting law is a perpetual threat to many species, including the duiker. Most hunters believe that the diminishing number of animals was due to overexploitation. The direct effects of hunting include overexploitation of target species and incidental hunting of nontargeted or rare species (because hunting is largely nonselective).
To avoid this outcome, viable methods of conserving duikers are access restriction and captive breeding. Access restriction involves imposing temporal or spatial restrictions on hunting duikers. Temporal restrictions include closing off certain seasons, such as the main birth season, to hunting; spatial restrictions include closing off certain regions where endangered duikers are found. Captive breeding has been used and is often looked to as a solution to ensuring the survival of the duiker population; however, due to the duikers' low reproduction rate, even with the protection provided by the conservationists, captive breeding would not increase the overall population's growth rate.
The greatest challenge facing the conservation of duikers is the lack of sufficient knowledge regarding these organisms, coupled with their unique population dynamics. The need is to not only thoroughly understand their population dynamics, but also establish methods to differentiate among the various species.
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