A primate is a eutherian mammal constituting the taxonomic order Primates. Primates arose 85–55 million years ago from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, altered shoulder girdle, dexterous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g, to the eastern gorilla, weighing over 200 kg. There are 190 -- 448 species of living primates, depending on. New primate species continue to be discovered: over 25 species were described in the first decade of the 2000s, eleven since 2010. Primates are divided into two distinct suborders; the first is the strepsirrhines - lemurs and lorisids. The second is haplorhines - the "dry-nosed" primates - tarsier and ape clades, the last of these including humans. Simians are monkeys and apes, cladistically including: the catarrhines consisting of the Old World monkeys and apes.
Forty million years ago, simians from Africa migrated to South America by drifting on debris, gave rise to the New World monkeys. Twenty five million years ago the remaining Old World simians split into Old World monkeys. Common names for the simians are the baboons, macaques and great apes. Primates have large brains compared to other mammals, as well as an increased reliance on visual acuity at the expense of the sense of smell, the dominant sensory system in most mammals; these features are more developed in monkeys and apes, noticeably less so in lorises and lemurs. Some primates are trichromats, with three independent channels for conveying color information. Except for apes, primates have tails. Most primates have opposable thumbs. Many species are sexually dimorphic. Primates have slower rates of development than other sized mammals, reach maturity and have longer lifespans. Depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members; some primates, including gorillas and baboons, are terrestrial rather than arboreal, but all species have adaptations for climbing trees.
Arboreal locomotion techniques used include leaping from tree to tree and swinging between branches of trees. Primates are among the most social of animals, forming pairs or family groups, uni-male harems, multi-male/multi-female groups. Non-human primates have at four types of social systems, many defined by the amount of movement by adolescent females between groups. Most primate species remain at least arboreal: the exceptions are some great apes and humans, who left the trees for the ground and now inhabit every continent. Close interactions between humans and non-human primates can create opportunities for the transmission of zoonotic diseases virus diseases, including herpes, ebola and hepatitis. Thousands of non-human primates are used in research around the world because of their psychological and physiological similarity to humans. About 60% of primate species are threatened with extinction. Common threats include deforestation, forest fragmentation, monkey drives, primate hunting for use in medicines, as pets, for food.
Large-scale tropical forest clearing for agriculture most threatens primates. The English name "primates" is derived from Old French or French primat, from a noun use of Latin primat-, from primus; the name was given by Carl Linnaeus. The relationships among the different groups of primates were not understood until recently, so the used terms are somewhat confused. For example, "ape" has been used either as an alternative for "monkey" or for any tailless human-like primate. Sir Wilfrid Le Gros Clark was one of the primatologists who developed the idea of trends in primate evolution and the methodology of arranging the living members of an order into an "ascending series" leading to humans. Used names for groups of primates such as "prosimians", "monkeys", "lesser apes", "great apes" reflect this methodology. According to our current understanding of the evolutionary history of the primates, several of these groups are paraphyletic: a paraphyletic group is one which does not include all the descendants of the group's common ancestor.
In contrast with Clark's methodology, modern classifications identify only those groupings that are monophyletic. The cladogram below shows one possible classification sequence of the living primates: groups that use common names are shown on the right. All groups with scientific names are monophyletic, the sequence of scientific classification reflects the evolution
Rodents are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents, they are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments. Species can be fossorial, or semiaquatic. Well-known rodents include mice, squirrels, prairie dogs, chinchillas, beavers, guinea pigs, hamsters and capybaras. Other animals such as rabbits and pikas, whose incisors grow continually, were once included with them, but are now considered to be in a separate order, the Lagomorpha. Nonetheless and Lagomorpha are sister groups, sharing a most recent common ancestor and forming the clade of Glires. Most rodents are small animals with robust bodies, short limbs, long tails, they use their sharp incisors to gnaw food, excavate burrows, defend themselves. Most eat seeds or other plant material, they tend to be social animals and many species live in societies with complex ways of communicating with each other.
Mating among rodents can vary from monogamy, to polygyny, to promiscuity. Many have litters of altricial young, while others are precocial at birth; the rodent fossil record dates back to the Paleocene on the supercontinent of Laurasia. Rodents diversified in the Eocene, as they spread across continents, sometimes crossing oceans. Rodents reached both South America and Madagascar from Africa and were the only terrestrial placental mammals to reach and colonize Australia. Rodents have been used as food, for clothing, as pets, as laboratory animals in research; some species, in particular, the brown rat, the black rat, the house mouse, are serious pests and spoiling food stored by humans and spreading diseases. Accidentally introduced species of rodents are considered to be invasive and have caused the extinction of numerous species, such as island birds isolated from land-based predators; the distinguishing feature of the rodents is their pairs of continuously growing, razor-sharp, open-rooted incisors.
These incisors little enamel on the back. Because they do not stop growing, the animal must continue to wear them down so that they do not reach and pierce the skull; as the incisors grind against each other, the softer dentine on the rear of the teeth wears away, leaving the sharp enamel edge shaped like the blade of a chisel. Most species have up to 22 teeth with no canines or anterior premolars. A gap, or diastema, occurs between the cheek teeth in most species; this allows rodents to suck in their cheeks or lips to shield their mouth and throat from wood shavings and other inedible material, discarding this waste from the sides of their mouths. Chinchillas and guinea pigs have a high-fiber diet. In many species, the molars are large, intricately structured, cusped or ridged. Rodent molars are well equipped to grind food into small particles; the jaw musculature is strong. The lower jaw is pulled backwards during chewing. Rodent groups differ in the arrangement of the jaw muscles and associated skull structures, both from other mammals and amongst themselves.
The Sciuromorpha, such as the eastern grey squirrel, have a large deep masseter, making them efficient at biting with the incisors. The Myomorpha, such as the brown rat, have enlarged temporalis muscles, making them able to chew powerfully with their molars; the Hystricomorpha, such as the guinea pig, have larger superficial masseter muscles and smaller deep masseter muscles than rats or squirrels making them less efficient at biting with the incisors, but their enlarged internal pterygoid muscles may allow them to move the jaw further sideways when chewing. The cheek pouch is a specific morphological feature used for storing food and is evident in particular subgroups of rodents like kangaroo rats, hamsters and gophers which have two bags that may range from the mouth to the front of the shoulders. True mice and rats do not contain this structure but their cheeks are elastic due to a high degree of musculature and innervation in the region. While the largest species, the capybara, can weigh as much as 66 kg, most rodents weigh less than 100 g.
The smallest rodent is the Baluchistan pygmy jerboa, which averages only 4.4 cm in head and body length, with adult females weighing only 3.75 g. Rodents have wide-ranging morphologies, but have squat bodies and short limbs; the fore limbs have five digits, including an opposable thumb, while the hind limbs have three to five digits. The elbow gives the forearms great flexibility; the majority of species are plantigrade, walking on both the palms and soles of their feet, have claw-like nails. The nails of burrowing species tend to be long and strong, while arboreal rodents have shorter, sharper nails. Rodent species use a wide variety of methods of locomotion including quadrupedal walking, burrowing, bipedal hopping and gliding. Scaly-tailed squirrels and flying squirrels, although not related, can both glide from tree to tree using parachute-like membranes that stretch from the fore to the hind limbs; the agouti is antelope-like, being digitigrade and having hoof-like nails. The majority of rodents have tails, which can be of many shapes and siz
Africa is the world's second largest and second most-populous continent, being behind Asia in both categories. At about 30.3 million km2 including adjacent islands, it covers 6% of Earth's total surface area and 20% of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the world's human population. The continent is surrounded by the Mediterranean Sea to the north, the Isthmus of Suez and the Red Sea to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west; the continent includes various archipelagos. It contains 54 recognised sovereign states, nine territories and two de facto independent states with limited or no recognition; the majority of the continent and its countries are in the Northern Hemisphere, with a substantial portion and number of countries in the Southern Hemisphere. Africa's average population is the youngest amongst all the continents. Algeria is Africa's largest country by area, Nigeria is its largest by population. Africa central Eastern Africa, is accepted as the place of origin of humans and the Hominidae clade, as evidenced by the discovery of the earliest hominids and their ancestors as well as ones that have been dated to around 7 million years ago, including Sahelanthropus tchadensis, Australopithecus africanus, A. afarensis, Homo erectus, H. habilis and H. ergaster—the earliest Homo sapiens, found in Ethiopia, date to circa 200,000 years ago.
Africa encompasses numerous climate areas. Africa hosts a large diversity of ethnicities and languages. In the late 19th century, European countries colonised all of Africa. African nations cooperate through the establishment of the African Union, headquartered in Addis Ababa. Afri was a Latin name used to refer to the inhabitants of then-known northern Africa to the west of the Nile river, in its widest sense referred to all lands south of the Mediterranean; this name seems to have referred to a native Libyan tribe, an ancestor of modern Berbers. The name had been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri meaning "cave", in reference to cave dwellers; the same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, a Berber tribe from Yafran in northwestern Libya. Under Roman rule, Carthage became the capital of the province it named Africa Proconsularis, following its defeat of the Carthaginians in the Third Punic War in 146 BC, which included the coastal part of modern Libya.
The Latin suffix -ica can sometimes be used to denote a land. The Muslim region of Ifriqiya, following its conquest of the Byzantine Empire's Exarchatus Africae preserved a form of the name. According to the Romans, Africa lay to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between the two continents by the geographer Ptolemy, indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa; as Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": The 1st-century Jewish historian Flavius Josephus asserted that it was named for Epher, grandson of Abraham according to Gen. 25:4, whose descendants, he claimed, had invaded Libya. Isidore of Seville in his 7th-century Etymologiae XIV.5.2. Suggests "Africa comes from the Latin aprica, meaning "sunny".
Massey, in 1881, stated that Africa is derived from the Egyptian af-rui-ka, meaning "to turn toward the opening of the Ka." The Ka is the energetic double of every person and the "opening of the Ka" refers to a womb or birthplace. Africa would be, for the Egyptians, "the birthplace." Michèle Fruyt in 1976 proposed linking the Latin word with africus "south wind", which would be of Umbrian origin and mean "rainy wind". Robert R. Stieglitz of Rutgers University in 1984 proposed: "The name Africa, derived from the Latin *Aphir-ic-a, is cognate to Hebrew Ophir." Ibn Khallikan and some other historians claim that the name of Africa came from a Himyarite king called Afrikin ibn Kais ibn Saifi called "Afrikus son of Abrahah" who subdued Ifriqiya. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation as early as 7 million years ago.
Fossil remains of several species of early apelike humans thought to have evolved into modern man, such as Australopithecus afarensis (radiometrically dated to 3.9–3.0 million years BP, Paranthropus boisei and Homo ergaster have been discovered. After the evolution of Homo sapiens sapiens 150,000 to 100,000 years BP in Africa, the continent was populated by groups of hunter-gatherers; these first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to 50,000 years BP, exiting the continent eith
Bears are carnivoran mammals of the family Ursidae. They are classified as doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and in the Southern Hemisphere. Bears are found on the continents of North America, South America and Asia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade paws with five nonretractile claws, short tails. While the polar bear is carnivorous, the giant panda feeds entirely on bamboo, the remaining six species are omnivorous with varied diets. With the exception of courting individuals and mothers with their young, bears are solitary animals, they may have an excellent sense of smell. Despite their heavy build and awkward gait, they are adept runners and swimmers. Bears use shelters, such as logs, as their dens. Bears have been hunted since prehistoric times for their fur. With their powerful physical presence, they play a prominent role in the arts and other cultural aspects of various human societies.
In modern times, bears have come under pressure through encroachment on their habitats and illegal trade in bear parts, including the Asian bile bear market. The IUCN lists six bear species as vulnerable or endangered, least concern species, such as the brown bear, are at risk of extirpation in certain countries; the poaching and international trade of these most threatened populations are prohibited, but still ongoing. The English word "bear" comes from Old English bera and belongs to a family of names for the bear in Germanic languages, such as Swedish björn used as a first name; this form is conventionally said to be related to a Proto-Indo-European word for "brown", so that "bear" would mean "the brown one". However, Ringe notes that while this etymology is semantically plausible, a word meaning "brown" of this form cannot be found in Proto-Indo-European, he suggests instead that "bear" is from the Proto-Indo-European word *ǵʰwḗr- ~ *ǵʰwér "wild animal". This terminology for the animal originated as a taboo avoidance term: proto-Germanic tribes replaced their original word for bear—arkto—with this euphemistic expression out of fear that speaking the animal's true name might cause it to appear.
According to author Ralph Keyes, this is the oldest known euphemism. Bear taxon names such as Arctoidea and Helarctos come from the ancient Greek word ἄρκτος, meaning bear, as do the names "arctic" and "antarctic", from the constellation Ursa Major, the "Great Bear", prominent in the northern sky. Bear taxon names such as Ursidae and Ursus come from he-bear/she-bear; the female first name "Ursula" derived from a Christian saint's name, means "little she-bear". In Switzerland, the male first name "Urs" is popular, while the name of the canton and city of Bern is derived from Bär, German for bear; the Germanic name Bernard means "bear-brave", "bear-hardy", or "bold bear". The Old English name Beowulf is a kenning; the family Ursidae is one of nine families in the suborder Caniformia, or "doglike" carnivorans, within the order Carnivora. Bears' closest living relatives are the pinnipeds and musteloids. Modern bears comprise eight species in three subfamilies: Ailuropodinae and Ursinae. Nuclear chromosome analysis show that the karyotype of the six ursine bears is nearly identical, with each having 74 chromosomes, whereas the giant panda has 42 chromosomes and the spectacled bear 52.
These smaller numbers can be explained by the fusing of some chromosomes, the banding patterns on these match those of the ursine species, but differ from those of procyonids, which supports the inclusion of these two species in Ursidae rather than in Procyonidae, where they had been placed by some earlier authorities. The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including Parictis and the younger Allocyon, both from North America; these animals looked different from today's bears, being small and raccoon-like in overall appearance, with diets more similar to that of a badger. Parictis does not appear in Africa until the Miocene, it is unclear whether late-Eocene ursids were present in Eurasia, although faunal exchange across the Bering land bridge may have been possible during a major sea level low stand as early as the late Eocene and continuing into the early Oligocene. European genera morphologically similar to Allocyon, to the much younger American Kolponomos, are known from the Oligocene, including Amphicticeps and Amphicynodon.
There has been various morphological evidence linking amphicynodontines with pinnipeds, as both groups were semi-aquatic, otter-like mammals. In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular evidence supports bears being the closet living relatives to pinnipeds; the raccoon-sized, dog-like Cephalogale is the oldest-known member of the subfamily Hemicyoninae, which first appeared during the middle Oligocene in Eurasia about 30 Mya
The lowland nyala or nyala, is a spiral-horned antelope native to southern Africa. It is a species of the family Bovidae and genus Nyala considered to be in the genus Tragelaphus, it was first described in 1849 by George French Angas. The body length is 135–195 cm, it weighs 55–140 kg; the coat is rusty or rufous brown in females and juveniles, but grows a dark brown or slate grey tinged with blue, in adult males. Females and young males have ten or more white stripes on their sides. Only males have 60 -- 83 cm long and yellow-tipped, it exhibits the highest sexual dimorphism among the spiral-horned antelopes. The nyala is active in the early morning and the late afternoon, it browses during the day if temperatures are 20–30 °C and during the night in the rainy season. As a herbivore, the nyala feeds upon foliage and grasses, with sufficient fresh water. A shy animal, it prefers water holes rather than open spaces; the nyala does not show signs of territoriality, individuals areas can overlap each others.
They are cautious creatures. Old males live alone; these inhabit thickets within dry savanna woodlands. The main predators of the nyala are lion and Cape hunting dog, while baboons and raptorial birds hunt for the juveniles. Mating peaks during spring and autumn. Males and females are sexually mature at 18 and 11–12 months of age though they are immature until five years old. After a gestational period of seven months, a single calf is born; the nyala's range includes Malawi, South Africa and Zimbabwe. It has been introduced to Botswana and Namibia, reintroduced to Swaziland, where it had been extinct since the 1950s, its population is stable and it has been listed as of Least Concern by the International Union for Conservation of Nature. The principal threats to the species are habitat loss resulting from human settlement; the males are prized as game animals in Africa. The nyala was first described by George French Angas, an English naturalist, in 1849; the scientific name of nyala is Tragelaphus angasii.
The name angasii is attributed to Angas, who said that Mr. Gray had named this species after Angas' father, George Fife Angas, Esq. of South Australia. But, according to Article 50.1.1 of the International Code of Zoological Nomenclature and International Commission on Zoological Nomenclature, this is insufficient to state Gray as the author. The name "nyala" is the Tsonga name for this antelope, the source of the English, along with Zulu "inyala", its first known use was in 1899. The word has a Bantu origin, similar to the Venda word dzì-nyálà; the nyala is the second taxon to branch off from the tragelaphine family tree just after the lesser kudu. As the nyala line has remained separate for a considerable amount of time, it has now been placed in its own monotypic genus Nyala. Nyala was proposed in 1912 by American zoologist Edmund Heller, the one who had proposed Ammelaphus, but not recognized, was only re-established as a valid genus in 2011 by Peter Grubb and Colin Groves. While Nyala is the accepted genus, it is still considered as a species of Tragelaphus.
In 2005, Sandi Willows-Munro and colleagues carried out a mitochondrial analysis of the nine Tragelaphus species. MtDNA and nDNA data were compared; the results showed that the tribe Tragelaphini is monophyletic with the lesser kudu basal in the phylogeny, followed by the nyala. On the basis of mitochondrial data, studies have estimated that the lesser kudu separated from its sister clade around 13.7 million years ago. On the other hand, the nuclear data shows that lesser kudu and nyala form a clade, collectively separated from the sister clade 13.8 million years ago. The nyala has 56 female chromosomes; the Y chromosome has been translocated onto the 14th chromosome, as in other tragelaphids, but no inversion of the Y chromosome occurs. Cranial studies have shown that the mountain nyala and nyala, though sharing a common name, are distant relatives. Fossil evidence suggests. Genetic evidence suggests that the proto-nyala had some early hybridization with the proto-lesser kudu, but the two have remained separate long after this crossing.
The nyala is a middle-sized antelope, between a bushbuck and a kudu. It is considered the most sexually dimorphic antelope; the nyala is between 135–195 cm in head-and-body length. The male stands up to 110 cm, the female is up to 90 cm tall. Males weigh 98 -- 125 kg. Life expectancy of the nyala is about 19 years; the coat is rusty or rufous brown in juveniles. But it grows a dark brown or slate grey in adult males with a bluish tinge. Females and young males have ten or more white vertical stripes on their sides. Other markings are visible on the face, throat and thighs. Stripes are reduced or absent in older males. Both males and females have a white chevron between their eyes, a 40–55 cm long bushy tail white underside. Both sexes have a dorsal crest of hair running right from the back of the head to the end of the tail. Males have another line of hair along the midline of their belly. Only the males have horns. Horns are 60 -- 83 cm yellow-tipped. There are two twists; the spoor is larger. It is 5–6 cm (2.0–2
South Africa the Republic of South Africa, is the southernmost country in Africa. It is bounded to the south by 2,798 kilometres of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans. South Africa is the largest country in Southern Africa and the 25th-largest country in the world by land area and, with over 57 million people, is the world's 24th-most populous nation, it is the southernmost country on the mainland of the Eastern Hemisphere. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different African languages, nine of which have official status; the remaining population consists of Africa's largest communities of European and multiracial ancestry. South Africa is a multiethnic society encompassing a wide variety of cultures and religions, its pluralistic makeup is reflected in the constitution's recognition of 11 official languages, the fourth highest number in the world. Two of these languages are of European origin: Afrikaans developed from Dutch and serves as the first language of most coloured and white South Africans.
The country is one of the few in Africa never to have had a coup d'état, regular elections have been held for a century. However, the vast majority of black South Africans were not enfranchised until 1994. During the 20th century, the black majority sought to recover its rights from the dominant white minority, with this struggle playing a large role in the country's recent history and politics; the National Party imposed apartheid in 1948. After a long and sometimes violent struggle by the African National Congress and other anti-apartheid activists both inside and outside the country, the repeal of discriminatory laws began in 1990. Since 1994, all ethnic and linguistic groups have held political representation in the country's liberal democracy, which comprises a parliamentary republic and nine provinces. South Africa is referred to as the "rainbow nation" to describe the country's multicultural diversity in the wake of apartheid; the World Bank classifies South Africa as an upper-middle-income economy, a newly industrialised country.
Its economy is the second-largest in Africa, the 34th-largest in the world. In terms of purchasing power parity, South Africa has the seventh-highest per capita income in Africa; however and inequality remain widespread, with about a quarter of the population unemployed and living on less than US$1.25 a day. South Africa has been identified as a middle power in international affairs, maintains significant regional influence; the name "South Africa" is derived from the country's geographic location at the southern tip of Africa. Upon formation, the country was named the Union of South Africa in English, reflecting its origin from the unification of four separate British colonies. Since 1961, the long form name in English has been the "Republic of South Africa". In Dutch, the country was named Republiek van Zuid-Afrika, replaced in 1983 by the Afrikaans Republiek van Suid-Afrika. Since 1994, the Republic has had an official name in each of its 11 official languages. Mzansi, derived from the Xhosa noun umzantsi meaning "south", is a colloquial name for South Africa, while some Pan-Africanist political parties prefer the term "Azania".
South Africa contains human-fossil sites in the world. Archaeologists have recovered extensive fossil remains from a series of caves in Gauteng Province; the area, a UNESCO World Heritage site, has been branded "the Cradle of Humankind". The sites include one of the richest sites for hominin fossils in the world. Other sites include Gondolin Cave Kromdraai, Coopers Cave and Malapa. Raymond Dart identified the first hominin fossil discovered in Africa, the Taung Child in 1924. Further hominin remains have come from the sites of Makapansgat in Limpopo Province and Florisbad in the Free State Province, Border Cave in KwaZulu-Natal Province, Klasies River Mouth in Eastern Cape Province and Pinnacle Point and Die Kelders Cave in Western Cape Province; these finds suggest that various hominid species existed in South Africa from about three million years ago, starting with Australopithecus africanus. There followed species including Australopithecus sediba, Homo ergaster, Homo erectus, Homo rhodesiensis, Homo helmei, Homo naledi and modern humans.
Modern humans have inhabited Southern Africa for at least 170,000 years. Various researchers have located pebble tools within the Vaal River valley. Settlements of Bantu-speaking peoples, who were iron-using agriculturists and herdsmen, were present south of the Limpopo River by the 4th or 5th century CE, they displaced and absorbed the original Khoisan speakers, the Khoikhoi and San peoples. The Bantu moved south; the earliest ironworks in modern-day KwaZulu-Natal Province are believed to date from around 1050. The southernmost group was the Xhosa people, whose language incorporates certain linguistic traits from the earlier Khoisan people; the Xhosa reached the Great Fish River, in today's Eastern Cape Province. As they migrated, these larger Iron Age populations
A duiker is a small to medium-sized brown antelope native to sub-Saharan Africa, found in wooded areas. The 22 extant species, including three sometimes considered to be subspecies of the other species, form the subfamily Cephalophinae; 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 and Sylvicapra; 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" comes from the combination of the New Latin word cephal, meaning head, the Greek word lophos, meaning crest; 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 dive into vegetation for cover. The three disputed species in Cephalophus are Brooke's duiker, Ruwenzori duiker, the white-legged duiker. Considered to be a subspecies of Ogilby's duiker, 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 considered to be a subspecies of the black-fronted duiker. 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, west African red duikers. Abbott's duiker, the bay duiker, Jentink's duiker and the yellow-backed duiker were classified as the giant duikers; the east African red duikers include the black-fronted duiker, Harvey's duiker, red-flanked duiker, red forest duiker, Ruwenzori duiker, white-bellied duiker.
The third group, the west African red duikers, comprises the black duiker, Ogilby's duiker, Peters's duiker, Weyns's duiker. However, the status of two species, Aders's duiker and zebra duiker, remained dubious. In 2012, Anne R. Johnston and colleagues constructed a cladogram of the subfamily Cephalophinae based on mitochondrial analysis. Duikers are split into two groups based on their habitat - bush duikers. All forest species inhabit the rainforests of sub-Saharan Africa]], while the only known bush duiker, grey common duiker occupies savannas. Duikers are shy, elusive creatures with a fondness for dense cover; because of their rarity and interspersed population, not much is known about duikers. In tropical rainforest zones of Africa, people nonselectively hunt duikers for their hide and horns at unsustainable rates. Population trends for all species of duikers, excluding the common duiker and the smallest blue duiker, are decreasing. Duikers range from the 3 kg blue duiker to the 70 kg yellow-backed duiker.
With their bodies low to the ground and with short horns, forest duikers are built to navigate through dense rainforests and dive into bushes when threatened. 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. Duikers 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. Besides reproduction, duikers behave in 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. Body size is proportional to the amount of food intake and the size of food. Anatomical features such as “the head and neck shape” 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.
In 2001, Helen Newing's study in West Africa on the interactions of duikers found that body size, “habitat preference, 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". However, although some species are yet to be considered ‘endangered’, because of the repeated damage and Habitat fragmentation of their habitat by human activities, such specialization of the niches are becoming impaired and are contributing to