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79-505: The okapi ( / oʊ ˈ k ɑː p iː / ; Okapia johnstoni ), also known as the forest giraffe , Congolese giraffe and zebra giraffe , is an artiodactyl mammal that is endemic to the northeast Democratic Republic of the Congo in central Africa. However, non-invasive genetic identification has suggested that a population has occurred south-west of the Congo River as well. It
158-493: A "horse", Sclater named the species Equus johnstoni . Subsequently, zoologist Ray Lankester declared that the okapi represented an unknown genus of the Giraffidae , which he placed in its own genus, Okapia , and assigned the name Okapia johnstoni to the species. In 1902, Swiss zoologist Charles Immanuel Forsyth Major suggested the inclusion of O. johnstoni in the extinct giraffid subfamily Palaeotraginae . However,
237-409: A few bumps. In contrast, camels and ruminants have bumps that are crescent-shaped cusps ( selenodont ). Philip Sclater Philip Lutley Sclater FRS FRGS FZS FLS (4 November 1829 – 27 June 1913) was an English lawyer and zoologist . In zoology, he was an expert ornithologist , and identified the main zoogeographic regions of the world. He was Secretary of
316-683: A few hours in darkness. They are essentially solitary, coming together only to breed. Okapis are herbivores , feeding on tree leaves and buds, grasses, ferns, fruits, and fungi . Rut in males and estrus in females does not depend on the season. In captivity, estrus cycles recur every 15 days. The gestational period is around 440 to 450 days long, following which usually a single calf is born. The juveniles are kept in hiding, and nursing takes place infrequently. Juveniles start taking solid food from three months, and weaning takes place at six months. Okapis inhabit canopy forests at altitudes of 500–1,500 m (1,600–4,900 ft). The International Union for
395-492: A few hours in darkness. They are essentially solitary, coming together only to breed. They have overlapping home ranges and typically occur at densities around 0.6 animals per square kilometre. Male home ranges average 13 km (5.0 sq mi), while female home ranges average 3–5 km (1.2–1.9 sq mi). Males migrate continuously, while females are sedentary. Males often mark territories and bushes with their urine, while females use common defecation sites. Grooming
474-423: A long neck, and large, flexible ears. Its coat is a chocolate to reddish brown, much in contrast with the white horizontal stripes and rings on the legs, and white ankles. Male okapis have short, distinct horn-like protuberances on their heads called ossicones , less than 15 cm (5.9 in) in length. Females possess hair whorls , and ossicones are absent. Okapis are primarily diurnal , but may be active for
553-576: A similar aquatic lifestyle. Hippopotamuses appeared in the late Miocene and occupied Africa and Asia—they never got to the Americas. The camels ( Tylopoda ) were, during large parts of the Cenozoic , limited to North America; early forms like Cainotheriidae occupied Europe. Among the North American camels were groups like the stocky, short-legged Merycoidodontidae . They first appeared in
632-477: A simple stomach that digests food. Thus, they were grouped together as non-ruminants (Porcine). All other even-toed ungulates have molars with a selenodont construction (crescent-shaped cusps) and have the ability to ruminate , which requires regurgitating food and re-chewing it. Differences in stomach construction indicated that rumination evolved independently between tylopods and ruminants ; therefore, tylopods were excluded from Ruminantia . The taxonomy that
711-474: A slim build, lanky legs, and a long tail. Their hind legs were much longer than their front legs. The early to middle Eocene saw the emergence of the ancestors of most of today's mammals. Two formerly widespread, but now extinct, families of even-toed ungulates were Entelodontidae and Anthracotheriidae . Entelodonts existed from the middle Eocene to the early Miocene in Eurasia and North America. They had
790-473: A stocky body with short legs and a massive head, which was characterized by two humps on the lower jaw bone. Anthracotheres had a large, porcine ( pig -like) build, with short legs and an elongated muzzle . This group appeared in the middle Eocene up until the Pliocene , and spread throughout Eurasia, Africa, and North America. Anthracotheres are thought to be the ancestors of hippos, and, likewise, probably led
869-424: A very flexible body, contributing to their speed by increasing their stride length. Many even-toed ungulates have a relatively large head. The skull is elongated and rather narrow; the frontal bone is enlarged near the back and displaces the parietal bone , which forms only part of the side of the cranium (especially in ruminants). Four families of even-toed ungulates have cranial appendages. These Pecora (with
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#1732801718914948-761: Is 20–30 years. The okapi is endemic to the Democratic Republic of the Congo, where it occurs north and east of the Congo River . It ranges from the Maiko National Park northward to the Ituri rainforest , then through the river basins of the Rubi, Lake Tele , and Ebola to the west and the Ubangi River further north. Smaller populations exist west and south of the Congo River. It
1027-433: Is a common practice, focused at the earlobes and the neck. Okapis often rub their necks against trees, leaving a brown exudate . The male is protective of his territory, but allows females to pass through the domain to forage. Males visit female home ranges at breeding time. Although generally tranquil, the okapi can kick and butt with its head to show aggression. As the vocal cords are poorly developed, vocal communication
1106-544: Is also common in the Wamba and Epulu areas. It is extinct in Uganda . The okapi inhabits canopy forests at elevations of 500–1,500 m (1,600–4,900 ft). It occasionally uses seasonally inundated areas, but does not occur in gallery forests , swamp forests , and habitats disturbed by human settlements . In the wet season, it visits rocky inselbergs that offer forage uncommon elsewhere. Results of research conducted in
1185-439: Is born, weighing 14–30 kg (31–66 lb). The udder of the pregnant female starts swelling 2 months before parturition , and vulval discharges may occur. Parturition takes 3–4 hours, and the female stands throughout this period, though she may rest during brief intervals. The mother consumes the afterbirth and extensively grooms the infant. Her milk is very rich in proteins and low in fat. As in other ruminants,
1264-409: Is easily distinguished from its nearest extant relative, the giraffe. It is much smaller than the giraffe and shares more external similarities with bovids and cervids . Ossicones are present only in the male okapi, while both sexes of giraffe possess this feature. The okapi has large palatine sinuses (hollow cavities in the palate ), unique among the giraffids. Morphological features shared between
1343-583: Is mainly restricted to three sounds — "chuff" (contact calls used by both sexes), "moan" (by females during courtship) and "bleat" (by infants under stress). Individuals may engage in Flehmen response , a visual expression in which the animal curls back its upper lips, displays the teeth, and inhales through the mouth for a few seconds. The leopard is the main natural predator of the okapi. Okapis are herbivores , feeding on tree leaves and buds, branches , grasses , ferns , fruits, and fungi . They are unique in
1422-475: Is more adapted to a squeezing mastication , which is characteristic of omnivores . Camels and ruminants have fewer teeth; there is often a yawning diastema , a designated gap in the teeth where the molars are aligned for crushing plant matter. The incisors are often reduced in ruminants, and are completely absent in the upper jaw . The canines are enlarged and tusk-like in the Suina, and are used for digging in
1501-462: Is the only species in the genus Okapia . Although the okapi has striped markings reminiscent of zebras , it is most closely related to the giraffe . The okapi and the giraffe are the only living members of the family Giraffidae . The okapi stands about 1.5 m (4 ft 11 in) tall at the shoulder and has a typical body length around 2.5 m (8 ft 2 in). Its weight ranges from 200 to 350 kg (440 to 770 lb). It has
1580-445: Is the extant form of Palaeotragus . The okapi is sometimes referred to as a living fossil , as it has existed as a species over a long geological time period, and morphologically resembles more primitive forms (e.g. Samotherium ). In 2016, a genetic study found that the common ancestor of giraffe and okapi lived about 11.5 million years ago. The okapi is a medium-sized giraffid, standing 1.5 m (4 ft 11 in) tall at
1659-644: Is the presence of illegal armed groups around protected areas, inhibiting conservation and monitoring actions. A small population occurs north of the Virunga National Park , but lacks protection due to the presence of armed groups in the vicinity. In June 2012, a gang of poachers attacked the headquarters of the Okapi Wildlife Reserve , killing six guards and other staff as well as all 14 okapis at their breeding center. The Okapi Conservation Project , established in 1987, works towards
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#17328017189141738-708: Is therefore focused on anthracotheres (family Anthracotheriidae); one dating from the Eocene to Miocene was declared to be "hippo-like" upon discovery in the 19th century. A study from 2005 showed that the anthracotheres and hippopotamuses had very similar skulls , but differed in the adaptations of their teeth. It was nevertheless believed that cetaceans and anthracothereres descended from a common ancestor, and that hippopotamuses developed from anthracotheres. A study published in 2015 confirmed this, but also revealed that hippopotamuses were derived from older anthracotherians. The newly introduced genus Epirigenys from Eastern Africa
1817-525: Is thus the sister group of hippos. Linnaeus postulated a close relationship between camels and ruminants as early as the mid-1700s. Henri de Blainville recognized the similar anatomy of the limbs of pigs and hippos, and British zoologist Richard Owen coined the term "even-toed ungulates" and the scientific name "Artiodactyla" in 1848. Internal morphology (mainly the stomach and the molars) were used for classification. Suines (including pigs ) and hippopotamuses have molars with well-developed roots and
1896-568: The British Museum in 1886. At around the same time the museum was augmented by the collections of Gould, Salvin and Godman, Hume, and others to become the largest in the world. Among Sclater's more important books were Exotic Ornithology (1866–69) and Nomenclator Avium (1873), both with Osbert Salvin ; Argentine Ornithology (1888–89), with W.H. Hudson ; and The Book of Antelopes (1894–1900) with Oldfield Thomas . In June 1901 he received an honorary doctorate of Science (D.Sc.) from
1975-704: The EEP (European studbook) and ISB (Global studbook) are managed by Antwerp Zoo in Belgium, which was the first zoo to have an Okapi on display (in 1919), as well as one of the most successful in breeding them. In 1937, the Bronx Zoo became the first in North America to acquire an okapi. With one of the most successful breeding programs, 13 calves have been born there between 1991 and 2011. The San Diego Zoo has exhibited okapis since 1956, and their first okapi calf
2054-557: The Ituri Forest . In 1901, Sclater presented a painting of the okapi before the Zoological Society of London that depicted its physical features with some clarity. Much confusion arose regarding the taxonomical status of this newly discovered animal. Sir Harry Johnston himself called it a Helladotherium , or a relative of other extinct giraffids. Based on the description of the okapi by Pygmies, who referred to it as
2133-694: The Old World , exist today only in the Americas . South America was settled by even-toed ungulates only in the Pliocene, after the land bridge at the Isthmus of Panama formed some three million years ago. With only the peccaries, lamoids (or llamas ), and various species of capreoline deer , South America has comparatively fewer artiodactyl families than other continents, except Australia, which has no native species. The classification of artiodactyls
2212-536: The University of Oxford . On 16 October 1862 Sclater married Jane Anne Eliza Hunter Blair, daughter of Sir David Hunter-Blair, 3rd Baronet ; the couple had a daughter and four sons. Their eldest son, William Lutley Sclater , was also an ornithologist. Their third son, Captain Guy Lutley Sclater, died on 26 November 1914, aged 45, in the accidental explosion that sank HMS Bulwark . Philip Sclater
2291-713: The Zoological Society of London for 42 years, from 1860 to 1902. Sclater was born at Tangier Park, in Wootton St Lawrence , Hampshire , where his father William Lutley Sclater had a country house. George Sclater-Booth, 1st Baron Basing was Philip's elder brother. Philip grew up at Hoddington House where he took an early interest in birds. He was educated in school at Twyford and at thirteen went to Winchester College and later Corpus Christi College, Oxford where he studied scientific ornithology under Hugh Edwin Strickland . In 1851 he began to study law and
2370-717: The Zoological Society of London . In 1858, Sclater published a paper in the Proceedings of the Linnean Society , setting up six zoological regions which he called the Palaearctic , Aethiopian , Indian , Australasian , Nearctic , and Neotropical . These zoogeographic regions are still in use. He also developed the theory of Lemuria during 1864 to explain zoological coincidences relating Madagascar to India . In 1874 he became private secretary to his brother George Sclater-Booth , MP (later Lord Basing). He
2449-507: The hind legs have a reduction in the number of toes to three. The central axis of the leg is between the third and fourth toe. The first toe is missing in modern artiodactyls, and can only be found in now-extinct genera. The second and fifth toes are adapted differently between species: When camels have only two toes present, the claws are transformed into nails (while both are made of keratin , claws are curved and pointed while nails are flat and dull). These claws consist of three parts:
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2528-537: The order Artiodactyla ( / ˌ ɑːr t i oʊ ˈ d æ k t ɪ l ə / AR -tee-oh- DAK -tih-lə , from Ancient Greek ἄρτιος , ártios 'even' and δάκτυλος , dáktylos 'finger, toe'). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof ). The other three toes are either present, absent, vestigial , or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of
2607-412: The ruminants as the sister group of cetaceans. Subsequent studies established the close relationship between hippopotamuses and cetaceans; these studies were based on casein genes , SINEs , fibrinogen sequences, cytochrome and rRNA sequences, IRBP (and vWF ) gene sequences, adrenergic receptors , and apolipoproteins . In 2001, the fossil limbs of a Pakicetus (amphibioid cetacean
2686-765: The 20th century, it may have been depicted since the early fifth century BCE on the façade of the Apadana at Persepolis , a gift from the Ethiopian procession to the Achaemenid kingdom. For years, Europeans in Africa had heard of an animal that they came to call the African unicorn . The animal was brought to prominent European attention by speculation on its existence found in press reports covering Henry Morton Stanley 's journeys in 1887. In his travelogue of exploring
2765-610: The Congo, Stanley mentioned a kind of donkey that the natives called the atti , which scholars later identified as the okapi. When the British special commissioner in Uganda, Sir Harry Johnston , discovered some Pygmy inhabitants of the Congo being abducted by a showman for exhibition, he rescued them and promised to return them to their homes. The Pygmies fed Johnston's curiosity about the animal mentioned in Stanley's book. Johnston
2844-528: The Conservation of Nature and Natural Resources classifies the okapi as endangered . Major threats include habitat loss due to logging and human settlement. Illegal mining and extensive hunting for bushmeat and skin have also led to a decline in populations. The Okapi Conservation Project was established in 1987 to protect okapi populations. Although the okapi was unknown to the Western world until
2923-523: The Giraffidae first appeared in the early Miocene in Africa, having diverged from the superficially deer-like climacoceratids . Giraffids spread into Europe and Asia by the middle Miocene in a first radiation . Another radiation began in the Pliocene , but was terminated by a decline in diversity in the Pleistocene . Several important primitive giraffids existed more or less contemporaneously in
3002-542: The Ituri Forest as they are the only known mammal that feeds solely on understory vegetation, where they use their 18-inch-long (46 cm) tongues to selectively browse for suitable plants. The tongue is also used to groom their ears and eyes. They prefer to feed in treefall gaps . The okapi has been known to feed on over 100 species of plants, some of which are known to be poisonous to humans and other animals. Fecal analysis shows that none of those 100 species dominates
3081-462: The Miocene (23–10 million years ago), including Canthumeryx , Giraffokeryx , Palaeotragus , and Samotherium . According to palaeontologist and author Kathleen Hunt, Samotherium split into Okapia (18 million years ago) and Giraffa (12 million years ago). However, J. D. Skinner argued that Canthumeryx gave rise to the okapi and giraffe through the latter three genera and that the okapi
3160-711: The conservation of the okapi, as well as the growth of the indigenous Mbuti people . In November 2011, the White Oak Conservation center and Jacksonville Zoo and Gardens hosted an international meeting of the Okapi Species Survival Plan and the Okapi European Endangered Species Programme at Jacksonville , which was attended by representatives from zoos from the US, Europe, and Japan. The aim
3239-595: The diet of the okapi. Staple foods comprise shrubs and lianas . The main constituents of the diet are woody, dicotyledonous species; monocotyledonous plants are not eaten regularly. In the Ituri forest, the okapi feeds mainly upon the plant families Acanthaceae , Ebenaceae , Euphorbiaceae , Flacourtiaceae , Loganiaceae , Rubiaceae , and Violaceae . Female okapis become sexually mature at about one-and-a-half years old, while males reach maturity after two years. Rut in males and estrus in females does not depend on
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3318-462: The early Eocene (about 53 million years ago). Since these findings almost simultaneously appeared in Europe , Asia , and North America , it is very difficult to accurately determine the origin of artiodactyls. The fossils are classified as belonging to the family Diacodexeidae ; their best-known and best-preserved member is Diacodexis . These were small animals, some as small as a hare , with
3397-609: The early Cenozoic ( Paleocene and Eocene ), which had hooves instead of claws on their feet. Their molars were adapted to a carnivorous diet, resembling the teeth in modern toothed whales , and, unlike other mammals, had a uniform construction. The suspected relations can be shown as follows: Artiodactyla [REDACTED] Mesonychia † [REDACTED] Cetacea [REDACTED] Molecular findings and morphological indications suggest that artiodactyls, as traditionally defined, are paraphyletic with respect to cetaceans. Cetaceans are deeply nested within
3476-419: The exception of the musk deer ), have one of four types of cranial appendages: true horns, antlers , ossicones , or pronghorns . True horns have a bone core that is covered in a permanent sheath of keratin, and are found only in the bovids . Antlers are bony structures that are shed and replaced each year; they are found in deer (members of the family Cervidae ). They grow from a permanent outgrowth of
3555-426: The first month or two of life, which is hypothesized to help avoid predator detection in their most vulnerable phase of life. The growth rate of calves is appreciably high in the first few months of life, after which it gradually declines. Juveniles start taking solid food from 3 months, and weaning takes place at 6 months. Ossicone development in males takes 1 year after birth. The okapi's typical lifespan
3634-456: The five toes. Another difference between the two orders is that many artiodactyls (except for Suina ) digest plant cellulose in one or more stomach chambers rather than in their intestine (as perissodactyls do). Molecular biology, along with new fossil discoveries, has found that cetaceans ( whales , dolphins , and porpoises ) fall within this taxonomic branch, being most closely related to hippopotamuses . Some modern taxonomists thus apply
3713-1021: The former; the two groups together form a monophyletic taxon, for which the name Cetartiodactyla is sometimes used. Modern nomenclature divides Artiodactyla (or Cetartiodactyla) in four subordinate taxa: camelids (Tylopoda), pigs and peccaries (Suina), ruminants (Ruminantia), and hippos plus cetaceans (Whippomorpha). The presumed lineages within Artiodactyla can be represented in the following cladogram : Tylopoda (camels) [REDACTED] Suina (pigs) [REDACTED] Tragulidae (mouse deer) [REDACTED] Pecora (horn bearers) [REDACTED] Hippopotamidae (hippopotamuses) [REDACTED] Cetacea (whales) [REDACTED] The four summarized Artiodactyla taxa are divided into ten extant families: Although deer, musk deer, and pronghorns have traditionally been summarized as cervids (Cervioidea), molecular studies provide different—and inconsistent—results, so
3792-491: The front feet. Male okapis have short, hair-covered horn-like structures called ossicones , less than 15 cm (5.9 in) in length, which are similar in form and function to the ossicones of a giraffe . The okapi exhibits sexual dimorphism , with females 4.2 cm (1.7 in) taller on average, slightly redder, and lacking prominent ossicones, instead possessing hair whorls . The okapi shows several adaptations to its tropical habitat. The large number of rod cells in
3871-616: The frontal bone called the pedicle and can be branched, as in the white-tailed deer ( Odocoileus virginianus ), or palmate , as in the moose ( Alces alces ). Ossicones are permanent bone structures that fuse to the frontal or parietal bones during an animal's life and are found only in the Giraffidae . Pronghorns , while similar to horns in that they have keratinous sheaths covering permanent bone cores, are deciduous. All these cranial appendages can serve for posturing, battling for mating privilege, and for defense. In almost all cases, they are sexually dimorphic, and are often found only on
3950-416: The giraffe and the okapi include a similar gait – both use a pacing gait, stepping simultaneously with the front and the hind leg on the same side of the body, unlike other ungulates that walk by moving alternate legs on either side of the body – and a long, black tongue (longer in the okapi) useful for plucking buds and leaves, as well as for grooming. Okapis are primarily diurnal , but may be active for
4029-401: The ground and for defense. In ruminants, the males' upper canines are enlarged and used as a weapon in certain species (mouse deer, musk deer, water deer ); species with frontal weapons are usually missing the upper canines. The lower canines of ruminants resemble the incisors, so that these animals have eight uniform teeth in the frontal part of the lower jaw . The molars of porcine have only
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#17328017189144108-424: The infant can stand within 30 minutes of birth. Although generally similar to adults, newborn calves have long hairs around the eye (resembling false eyelashes), a long dorsal mane , and long white hairs in the stripes. These features gradually disappear and give way to the general appearance within a year. The juveniles are kept in hiding, and nursing takes place infrequently. Calves are known not to defecate for
4187-550: The late 1980s in a mixed Cynometra forest indicated that the okapi population density averaged 0.53 animals per square kilometre. In 2008, it was recorded in Virunga National Park . There is also evidence that okapis were also observed in the Semuliki Valley in Uganda by Europeans, but later became extinct in the late 1970s. The Semuliki Valley provides a similar habitat to the Congo Basin . The IUCN classifies
4266-538: The late Eocene and developed a great diversity of species in North America. Only in the late Miocene or early Pliocene did they migrate from North America into Eurasia. The North American varieties became extinct around 10,000 years ago. Suina (including pigs ) have been around since the Eocene. In the late Eocene or the Oligocene , two families stayed in Eurasia and Africa; the peccaries , which became extinct in
4345-407: The limbs are predominantly localized, which ensures that artiodactyls often have very slender legs. A clavicle is never present, and the scapula is very agile and swings back and forth for added mobility when running. The special construction of the legs causes the legs to be unable to rotate, which allows for greater stability when running at high speeds. In addition, many smaller artiodactyls have
4424-634: The males are consistently larger and heavier than the females. In deer, only the males boast antlers, and the horns of bovines are usually small or not present in females. Male Indian antelopes have a much darker coat than females. Almost all even-toed ungulates have fur, with the exception being the nearly hairless hippopotamus. Fur varies in length and coloration depending on the habitat. Species in cooler regions can shed their coat. Camouflaged coats come in colors of yellow, gray, brown, or black tones. Even-toed ungulates bear their name because they have an even number of toes (two or four)—in some peccaries,
4503-463: The males. One exception is the species Rangifer tarandus , known as reindeer in Europe or caribou in North America, where both sexes can grow antlers yearly, though the females' antlers are typically smaller and not always present. There are two trends in terms of teeth within Artiodactyla. The Suina and hippopotamuses have a relatively large number of teeth (with some pigs having 44); their dentition
4582-421: The mouse deer, often reaches a body length of only 45 centimeters (18 in) and a weight of 1.5 kilograms (3.3 lb). The largest member, the hippopotamus, can grow up to 5 meters (16 ft) in length and weigh 4.5 metric tons (5 short tons), and the giraffe can grow to be 5.5 meters (18 ft) tall and 4.7 meters (15 ft) in body length. All even-toed ungulates display some form of sexual dimorphism :
4661-948: The name Cetartiodactyla ( / s ɪ ˌ t ɑːr t i oʊ ˈ d æ k t ɪ l ə / ) to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers use " even-toed ungulates " to exclude cetaceans and only include terrestrial artiodactyls, making the term paraphyletic in nature. The roughly 270 land-based even-toed ungulate species include pigs , peccaries , hippopotamuses , antelopes , deer , giraffes , camels , llamas , alpacas , sheep , goats and cattle . Many are herbivores, but suids are omnivorous, whereas cetaceans are entirely carnivorous. Artiodactyls are also known by many extinct groups such as anoplotheres , cainotheriids , merycoidodonts , entelodonts , anthracotheres , basilosaurids , and palaeomerycids . Many artiodactyls are of great dietary, economic, and cultural importance to humans. The oldest fossils of even-toed ungulates date back to
4740-893: The okapi as endangered. It is fully protected under Congolese law. The Okapi Wildlife Reserve and Maiko National Park support significant populations of the okapi, though a steady decline in numbers has occurred due to several threats. Other areas of occurrence are the Rubi Tele Hunting Reserve ,the Abumombanzi Reserve,the Sankuru Nature Reserve , the Lomami National Park . Major threats include habitat loss due to logging and human settlement. Extensive hunting for bushmeat and skin and illegal mining have also led to population declines. A threat that has emerged quite recently
4819-442: The plate (top and sides), the sole (bottom), and the bale (rear). In general, the claws of the forelegs are wider and blunter than those of the hind legs, and they are farther apart. Aside from camels, all even-toed ungulates put just the tip of the foremost phalanx on the ground. In even-toed ungulates, the bones of the stylopodium (upper arm or thigh bone) and zygopodiums (tibia and fibula) are usually elongated. The muscles of
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#17328017189144898-413: The question of phylogenetic systematics of infraorder Pecora (the horned ruminants) for the time being, cannot be answered. Artiodactyls are generally quadrupeds . Two major body types are known: suinids and hippopotamuses are characterized by a stocky body, short legs, and a large head; camels and ruminants, though, have a more slender build and lanky legs. Size varies considerably; the smallest member,
4977-473: The retina facilitate night vision , and an efficient olfactory system is present. The large auditory bullae of the temporal bone allow a strong sense of hearing. The dental formula of the okapi is 0.0.3.3 3.1.3.3 . Teeth are low- crowned and finely cusped , and efficiently cut tender foliage. The large cecum and colon help in microbial digestion, and a quick rate of food passage allows for lower cell wall digestion than in other ruminants . The okapi
5056-405: The season. In captivity, estrous cycles recur every 15 days. The male and the female begin courtship by circling, smelling, and licking each other. The male shows his interest by extending his neck, tossing his head, and protruding one leg forward. This is followed by mounting and copulation . The gestational period is around 440 to 450 days long, following which usually a single calf
5135-472: The sequence with that of other living beings—the more similar they are, the more closely they are related. Comparison of even-toed ungulate and cetaceans genetic material has shown that the closest living relatives of whales and hippopotamuses is the paraphyletic group Artiodactyla. Dan Graur and Desmond Higgins were among the first to come to this conclusion, and included a paper published in 1994. However, they did not recognize hippopotamuses and classified
5214-577: The shoulder. Its average body length is about 2.5 m (8 ft 2 in) and its weight ranges from 200 to 350 kg (440 to 770 lb). It has a long neck, and large and flexible ears. In sharp contrast to the white horizontal stripes on the legs and white ankles, the okapi's coat is a chocolate to reddish brown. The distinctive stripes resemble those of a zebra. These features serve as an effective camouflage amidst dense vegetation. The face, throat, and chest are greyish white. Interdigital glands are present on all four feet, and are slightly larger on
5293-668: The size of a wolf) and Ichthyolestes (an early whale the size of a fox) were found in Pakistan. They were both archaeocetes ("ancient whales") from about 48 million years ago (in the Eocene). These findings showed that archaeocetes were more terrestrial than previously thought, and that the special construction of the talus (ankle bone) with a double-rolled joint surface, previously thought to be unique to even-toed ungulates, were also in early cetaceans. The mesonychians , another type of ungulate, did not show this special construction of
5372-403: The species was placed in its own subfamily Okapiinae, by Swedish palaeontologist Birger Bohlin in 1926, mainly due to the lack of a cingulum , a major feature of the palaeotragids. In 1986, Okapia was finally established as a sister genus of Giraffa on the basis of cladistic analysis. The two genera together with Palaeotragus constitute the tribe Giraffini. The earliest members of
5451-466: The talus, and thus was concluded to not have the same ancestors as cetaceans. The oldest cetaceans date back to the early Eocene (53 million years ago), whereas the oldest known hippopotamus dates back only to the Miocene (15 million years ago). The hippopotamids are descended from the anthracotheres, a family of semiaquatic and terrestrial artiodactyls that appeared in the late Eocene, and are thought to have resembled small- or narrow-headed hippos. Research
5530-479: The traditional order Artiodactyla and infraorder Cetacea are sometimes subsumed into the more inclusive Cetartiodactyla taxon. An alternative approach is to include both land-dwelling even-toed ungulates and ocean-dwelling cetaceans in a revised Artiodactyla taxon. In the 1990s, biological systematics used not only morphology and fossils to classify organisms, but also molecular biology . Molecular biology involves sequencing an organism's DNA and RNA and comparing
5609-736: Was Secretary of the Zoological Society of London from 1860 to 1902. He was briefly succeeded by his son, before the Council of the Society made a long-term appointment. In 1901 he described the okapi to western scientists although he never saw one alive. His office at 11 Hanover Square became a meeting place for all naturalists in London. Travellers and residents shared notes with him and he corresponded with thousands. His collection of birds grew to nine thousand and these he transferred to
5688-542: Was admitted a Fellow of Corpus Christi College. In 1856 he travelled to America and visited Lake Superior and the upper St. Croix River , canoeing down it to the Mississippi. Sclater wrote about this in "Illustrated travels". In Philadelphia he met Spencer Baird , John Cassin and Joseph Leidy at the Academy of Natural Sciences . After returning to England, he practised law for several years and attended meetings of
5767-2334: Was born in 1962. Since then, there have been more than 60 okapis born at the zoo and the nearby San Diego Zoo Safari Park , the most recent being Mosi, a male calf born on 21 July 2017 at the zoo. The Brookfield Zoo in Chicago has also greatly contributed to the captive population of okapis in accredited zoos. The zoo has had 28 okapi births since 1959. Other North American zoos that exhibit and breed okapis include: Denver Zoo and Cheyenne Mountain Zoo (Colorado); Houston Zoo , Dallas Zoo , and San Antonio Zoo (Texas); Disney's Animal Kingdom , White Oak Conservation , Zoo Miami , and ZooTampa at Lowry Park (Florida); Los Angeles Zoo , Sacramento Zoo , and San Diego Zoo (California); Saint Louis Zoo (Missouri); Cincinnati Zoo and Botanical Garden and Columbus Zoo and Aquarium (Ohio); Memphis Zoo and Nashville Zoo (Tennessee); The Maryland Zoo in Baltimore (Maryland); Sedgwick County Zoo and Tanganyika Wildlife Park (Kansas); Roosevelt Park Zoo (North Dakota); Henry Doorly Zoo and Aquarium (Nebraska); Philadelphia Zoo (Pennsylvania); Potawatomi Zoo (Indiana); Oklahoma City Zoo and Botanical Garden (Oklahoma); Blank Park Zoo (Iowa); and Potter Park Zoo (Michigan). In Europe, zoos that exhibit and breed okapis include: Chester Zoo , London Zoo , Marwell Zoo , The Wild Place , and Yorkshire Wildlife Park (United Kingdom); Dublin Zoo (Ireland); Berlin Zoo , Frankfurt Zoo , Wilhelma Zoo , Wuppertal Zoo , Cologne Zoo , and Leipzig Zoo (Germany); Zoo Basel (Switzerland); Copenhagen Zoo (Denmark); Rotterdam Zoo and Safaripark Beekse Bergen (Netherlands); Antwerp Zoo (Belgium); Dvůr Králové Zoo (Czech Republic); Wrocław Zoo (Poland); Bioparc Zoo de Doué and ZooParc de Beauval (France); and Lisbon Zoo (Portugal). In Asia, three Japanese zoos exhibit okapis: Ueno Zoo in Tokyo; Kanazawa Zoo and Zoorasia in Yokohama. Artiodactyl Cetartiodactyla Montgelard et al. 1997 Artiodactyls are placental mammals belonging to
5846-460: Was formally recognized as Okapia johnstoni . Okapia johnstoni was first described as Equus johnstoni by English zoologist Philip Lutley Sclater in 1901. The generic name Okapia derives either from the Mbuba name okapi or the related Lese Karo name o'api , while the specific name ( johnstoni ) is in recognition of Johnston, who first acquired an okapi specimen for science from
5925-426: Was hotly debated because ocean-dwelling cetaceans evolved from land-dwelling even-toed ungulates. Some semiaquatic even-toed ungulates ( hippopotamuses ) are more closely related to ocean-dwelling cetaceans than to other even-toed ungulates. Phylogenetic classification only recognizes monophyletic taxa; that is, groups that descend from a common ancestor and include all of its descendants. To address this problem,
6004-769: Was offered a permanent position in civil service but he declined. In 1875, he became President of the Biological Section of the British Association for the Advancement of Science , which he joined in 1847 as a member. He was elected as a member to the American Philosophical Society in 1873. Sclater was the founder and first editor of The Ibis , the journal of the British Ornithologists' Union . He
6083-399: Was puzzled by the okapi tracks the natives showed him; while he had expected to be on the trail of some sort of forest-dwelling horse, the tracks were of a cloven-hoofed beast. Though Johnston did not see an okapi himself, he did manage to obtain pieces of striped skin and eventually a skull. From this skull, the okapi was correctly classified as a relative of the giraffe; in 1901, the species
6162-547: Was to discuss the management of captive okapis and arrange support for okapi conservation. Many zoos in North America and Europe currently have okapis in captivity. Around 100 okapis are in accredited Association of Zoos and Aquariums (AZA) zoos. The okapi population is managed in America by the AZA's Species Survival Plan, a breeding program that works to ensure genetic diversity in the captive population of endangered animals, while
6241-621: Was widely accepted by the end of the 20th century was: Suidae [REDACTED] Hippopotamidae [REDACTED] Tylopoda [REDACTED] Tragulidae [REDACTED] Pecora [REDACTED] Modern cetaceans are highly adapted sea creatures which, morphologically, have little in common with land mammals; they are similar to other marine mammals , such as seals and sea cows , due to convergent evolution . However, they evolved from originally terrestrial mammals. The most likely ancestors were long thought to be mesonychians—large, carnivorous animals from
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