World history duiker pdf

They are found in world history duiker pdf wooded areas. The 22 extant species, including three sometimes considered to be subspecies of the other species, from the subfamily Cephalophinae.

Tragelaphus, based on Johnston et al. The subfamily Cephalophinae comprises three genera and 22 species, three of which are sometimes considered to be subspecies of the other species. A 2001 phylogenetic study divided Cephalophus into three distinct lineages: the giant duikers, east African red duikers and west African red duikers. 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 occupies savannas. Duikers range from the 3 kilogram blue duiker to the 70 kilogram yellow-backed duiker. With their body low to the ground and with very short horns, forest duikers are built to navigate effectively through dense rainforests and quickly dive into bushes when threatened. 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 grey duiker in which the females are distinctly larger than the males. Also, body size is proportional to the amount of food intake and the size of food. These differences specific to each species of duiker allow them to coexist by “limiting niche overlap”.

Due to their relative size and reserved nature, duikers’ primary defense mechanism is to hide from predators. Duikers are known for their extreme shyness, freezing at the slightest sign of a threat and diving into the nearest bush. For those duikers that travel alone, they choose to interact with other duikers once or twice a year, solely for the purpose of mating. Duikers prefer to live alone or as pairs in order 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. Jarman found that the more selective an organism’s diet is, the more dispersed their food will be, and consequently, the smaller the group becomes. Duikers are primarily browsers rather than grazers, eating leaves, shoots, seeds, fruit, buds and bark, and often following flocks of birds or troops of monkeys to take advantage of the fruit they drop. The smaller species, for example the blue duiker, generally tend to eat various seeds, while larger ones tend to feast more on larger fruits.

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 study done by Helen Newing in 2001 found that a correlation exists between body size and sleep pattern in duikers. Duikers are found sympatrically in many different regions. Most species dwell in the tropical rainforests of Central and West Africa, creating overlapping regions among different species of forest duikers.

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. Also, as indicated by the study of Helen Newing, there is a correlation between body size and diet. Larger animals have more robust digestive systems, stronger jaws, and wider necks, which allow them to consume lower quality foods, larger fruits and seeds. Similarly, Bay and Peters’s duikers can coexist because of their different sleep patterns. This allows the Peters’s duiker to eat its fruits by day, and the Bay duiker to eat what is left by night. Duikers live in an environment where even a subtle change in their life pattern can greatly impact the surrounding ecosystem.

Overexploitation of duikers affects their population as well as organisms that rely on them for survival. For instance, plants that depend on duikers for seed dispersal may lose their primary purpose of reproduction, and other organisms that depend on these particular plants as their resources would also be usurped of their major source of food. Duikers are often captured for bushmeat. In addition to the unnaturally high demand for bushmeat, unenforced hunting law is a perpetual threat to many species, including the duiker. In a study done by Anadu and others in 1988, it was found that most hunters believe that the diminishing number of animals was due to overexploitation. 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.

The greatest challenges facing the conservation of duikers are the lack of sufficient knowledge regarding these organisms coupled with their unique population dynamics. We need to not only thoroughly understand their population dynamics, but also establish methods to differentiate among the various species. Filoviruses such as Ebola, citing Georges et al. The WHO notes that risk of infection predominantly arises from slaughter and preparation of meat, and that consumption of properly cooked meat does not pose a risk. IUCN Red List of Threatened Species. Zoological Journal of the Linnean Society.