Duiker

The common name "duiker" comes from the Afrikaans word duik, or Dutch duiken - both mean "to dive", which refers to the practice of the animals to frequently dive into vegetation for cover. ==Description==

)'' skeleton on display at the Museum of Osteology Duikers are very shy, elusive creatures with a fondness for dense cover; those that tend to live in more open areas, for example, are quick to disappear into thickets for protection; because of their rarity and interspersed population, not much is known about duikers. Thus, further generalizations are widely based on the most commonly studied species: the red forest, blue, yellow-backed, and common grey duiker are commonly observed. Duikers range from the blue duiker to the yellow-backed duiker. Since the common grey duiker lives in more open areas, such as savannas, it has longer legs and vertical horns, which allow it to run faster and for longer distances; only the males, which are more confrontational and territorial, exhibit horns. Duikers also have well-developed preorbital glands, which resemble slits under their eyes, or in the cases of blue duikers, pedal glands on their hooves. Males use secretions from these glands to mark their territories. ==Taxonomy and phylogeny==

}} }} }} Duikers are split into two groups based on their habitat – forest and bush duikers. All forest species inhabit the rainforests of sub-Saharan Africa, while the only known bush duiker, grey common duiker (of the genus Sylvicapra) occupies savannas. The tribe Cephalophini (formerly the subfamily Cephalophinae) comprises three genera and 22 species, three of which are sometimes considered to be subspecies of the other species. The three genera include Cephalophus (15 species and three disputed taxa), Philantomba (three species), and Sylvicapra (one species). The subfamily was first described by British zoologist John Edward Gray in 1871 in Proceedings of the Zoological Society of London. The scientific name "Cephalophinae" probably comes from the combination of the New Latin word cephal, meaning head, and the Greek word lophos, meaning crest. 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. 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. 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 mitochondrial analysis. Species • Tribe Cephalophini :* Genus Cephalophus ::* Abbott's duiker, C. spadix ::* Aders's duiker, C. adersi ::* Bay duiker, C. dorsalis ::* Black duiker, C. niger ::* Black-fronted duiker, C. nigrifrons ::* Brooke's duiker, C. brookei (may be a subspecies of Ogilby's duiker) ::* Yellow-backed duiker, C. silvicultor ::* Zebra duiker, C. zebra :* Genus Philantomba ::* Blue duiker, P. monticola ::* Maxwell's duiker, P. maxwellii ::* Walter's duiker, P. walteri :* Genus Sylvicapra ::* Common duiker, S. grimmia == Behaviour ==

Outside of reproduction, duikers are solitary, behaving highly independently and preferring to act alone. This may explain, in part, the limited sexual size dimorphism shown by most duiker species, excluding the common duiker, in which the females are distinctly larger than the males. Interactions In 2001, Helen Newing's study in West Africa on the interactions of duikers found that body size, habitat preference, and activity patterns were the main differentiating factors among the seven species of duikers. These differences specific to each species of duiker allow them to coexist by limiting niche overlap. Male common duikers, especially the younger males, mark their territories also by defecation. Activity patterns Duikers can be diurnal, nocturnal, or both. Since the majority of the food source is available in the daytime, duiker evolution has rendered most duikers as diurnal. A correlation exists between body size and sleep pattern in duikers; while smaller to medium-sized duikers show increased activity and scavenge for food during the daytime, larger duikers are most active at night. red forest duikers are more observed in a less exploited regions such as the western Dja Reserve of Cameroon. == Ecology ==

Conservation of duikers has a direct and critical relationship with their ecology. Disruption of balance in the system leads to unprecedented competition, both interspecific and intraspecific. 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. == Conservation ==

in San Antonio, Texas Duikers live in an environment where even a subtle change in their life patterns can greatly impact the surrounding ecosystem. Two of the main factors that directly lead to duiker extinction are habitat loss and overexploitation. Constant urbanization and the process of "shifting agriculture" is gradually taking over many of duikers' habitats; at the same time, overexploitation is also permitting the overgrowth of other interacting species, resulting in an inevitable disruption of coexistence. In tropical rainforest zones of Africa, people nonselectively hunt duikers for their hide, meat, and horns at highly unsustainable rates. 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. 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. 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 protein 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). == See also ==