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Okapi
Male okapi at Beauval Zoo
Female okapi at Zoo Miami
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Giraffidae
Genus: Okapia
Lankester, 1901
Species:
O. johnstoni
Binomial name
Okapia johnstoni
(P.L. Sclater, 1901)
Range of the okapi

The okapi (/oʊˈkɑːpi/; Okapia johnstoni), also known as the forest giraffe,[2] zebra giraffe and Congolese giraffe,[dubious – discuss] 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.[3] It 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 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 a few hours in darkness. They are essentially solitary, coming together only to breed.[4] 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 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.

Etymology and taxonomy

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Although the okapi was unknown to the Western world until 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.[5][6]

For years, Europeans in Africa had heard of an animal that they came to call the African unicorn.[7][8] It 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 the Congo, Stanley mentioned a kind of donkey that the natives called the atti, which scholars later identified as the okapi.[9]

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 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.[10]

Illustration from an original painting by Sir Harry Johnston, based on preserved skins (1901)

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 was formally recognized as Okapia johnstoni.[11]

Okapia johnstoni was first described as Equus johnstoni by English zoologist Philip Lutley Sclater in 1901.[12] The generic name Okapia derives either from the Mbuba name okapi[13] 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 the Ituri Forest.[11][14]

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.[15] Based on the description of the okapi by Pygmies, who referred to it as a "horse", Sclater named the species Equus johnstoni.[16] 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.[17]

In 1902, Swiss zoologist Charles Immanuel Forsyth Major suggested the inclusion of O. johnstoni in the extinct giraffid subfamily Palaeotraginae. However, the species was placed in its own subfamily Okapiinae, by Swedish palaeontologist Birger Bohlin in 1926,[18] mainly due to the lack of a cingulum, a major feature of the palaeotragids.[19] 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.[20]

Evolution

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Despite the vast difference in neck length, the okapi (left) and the giraffe (right) both have seven cervical vertebrae (as do all mammals except for manatees and sloths).

The earliest members of 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.[21] Several important primitive giraffids existed more or less contemporaneously in 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).[22] However, J. D. Skinner argued that Canthumeryx gave rise to the okapi and giraffe through the latter three genera and that the okapi is the extant form of Palaeotragus.[23] 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).[17][24]

In 2016, a genetic study found that the common ancestor of giraffe and okapi lived about 11.5 million years ago.[25]

Description

[edit]
Male okapi displaying his striking horizontal stripes

The okapi is a medium-sized giraffid, standing 1.5 m (4 ft 11 in) tall at 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).[26] 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.[27] 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 the front feet.[28] 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.[29] 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.[30][31]

The okapi shows several adaptations to its tropical habitat. The large number of rod cells in 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 0.0.3.33.1.3.3.[28] 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.[32]

Head of a male okapi with damaged ossicones

The okapi 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 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[33] – and a long, black tongue (longer in the okapi) useful for plucking buds and leaves, as well as for grooming.[32]

Ecology and behaviour

[edit]

Okapis are primarily diurnal, but may be active for a few hours in darkness.[34] 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.[27] Male home ranges average 13 km2 (5.0 sq mi), while female home ranges average 3–5 km2 (1.2–1.9 sq mi). Males migrate continuously, while females are sedentary.[35] Males often mark territories and bushes with their urine, while females use common defecation sites. Grooming is a common practice, focused at the earlobes and the neck. Okapis often rub their necks against trees, leaving a brown exudate.[28]

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.[32] Although generally tranquil, the okapi can kick and butt with its head to show aggression. As the vocal cords are poorly developed, vocal communication 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.[28]

Diet

[edit]
The long tongue of the okapi

Okapis are herbivores, feeding on tree leaves and buds, branches, grasses, ferns, fruits, and fungi.[36] They are unique in 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.[37] 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 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.[28][35]

Reproduction

[edit]
A female okapi with her calf at White Oak Conservation

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 the season. In captivity, estrous cycles recur every 15 days.[32][38] 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.[30]

The gestational period is around 440 to 450 days long, following which usually a single calf 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.[32]

As in other ruminants, 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.[39] 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 the first month or two of life, which is hypothesized to help avoid predator detection in their most vulnerable phase of life.[40] 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 is 20–30 years.[28]

Distribution and habitat

[edit]

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 is also common in the Wamba and Epulu areas. It is extinct in Uganda.[1]

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 the late 1980s in a mixed Cynometra forest indicated that the okapi population density averaged 0.53 animals per square kilometre.[35] In 2008, it was recorded in Virunga National Park.[41] 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.[42] The Semuliki Valley provides a similar habitat to the Congo Basin.

Status

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Threats and conservation

[edit]
Okapi at Disney's Animal Kingdom

The IUCN classifies the okapi as endangered.[43] 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 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.[1] In June 2012, a gang of poachers attacked the headquarters of the Okapi Wildlife Reserve, killing six guards and other staff[44] as well as all 14 okapis at their breeding center.[45]

The Okapi Conservation Project, established in 1987, works towards the conservation of the okapi, as well as the growth of the indigenous Mbuti people.[1] 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 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.[46]

Okapis in zoos

[edit]
1960 Dutch newsreel about okapis in Diergaarde Blijdorp

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 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.[47][48]

In 1937, the Bronx Zoo became the first in North America to acquire an okapi.[49] With one of the most successful breeding programs, 13 calves have been born there between 1991 and 2011.[50] The San Diego Zoo has exhibited okapis since 1956, and their first okapi calf was born in 1962.[51] 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.[52] 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.[53]

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[54] (North Dakota); Henry Doorly Zoo and Aquarium (Nebraska); Philadelphia Zoo (Pennsylvania); Potawatomi Zoo[55] (Indiana); Oklahoma City Zoo and Botanical Garden (Oklahoma); Blank Park Zoo (Iowa);[56] and Potter Park Zoo (Michigan).[57]

In Europe, zoos that exhibit and breed okapis include: Chester Zoo, London Zoo, Marwell Zoo, The Wild Place,[58] and Yorkshire Wildlife Park[59] (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).[60]

In Asia, three Japanese zoos exhibit okapis: Ueno Zoo in Tokyo; Kanazawa Zoo and Zoorasia in Yokohama.[61]

See also

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References

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Further reading

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[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Okapi

View on Grokipedia
from Grokipedia
The okapi (Okapia johnstoni) is a giraffid and the only living relative of the (Giraffa camelopardalis), comprising the sole extant in its genus and endemic to the dense lowland rainforests of the . Characterized by a deep reddish-brown coat, horizontal white stripes on its forelegs and hindquarters that provide in dappled light, a short neck relative to its kin, and—in males—brief, fur-covered ossicones atop the head, the okapi employs a long, prehensile tongue exceeding 12 inches in length to strip foliage from trees and shrubs, its primary diet of leaves, fruits, and fungi. First confirmed to Western in 1901 through skins and skeletal remains obtained by British explorer Sir , and formally named Okapia johnstoni by E. Ray Lankester in honor of Johnston, the okapi shattered expectations of a forest-dwelling equine, instead revealing a basal giraffid lineage diverging from giraffes around 11-16 million years ago. Classified as Endangered on the since 2013, the okapi faces severe threats from due to , , and agricultural expansion, compounded by for and conflict-driven instability in its extent of occurrence (EOO) of 383,190 km², with no reliable current population estimate available.

Discovery and Historical Context

Indigenous Knowledge and Early Reports

Local tribes inhabiting the Ituri Forest region of the Democratic Republic of the Congo, such as the Lese and Mbuti pygmies, possessed empirical knowledge of the okapi long before external documentation, recognizing it as a secretive herbivore adapted to dense rainforest understory. These groups referred to the animal using terms like "o'api" among the Lese, denoting its elusive presence in the forest, and "atti" in accounts from the Wambutti (a Mbuti subgroup), emphasizing its donkey-like form without overt giraffe associations in initial oral descriptions. Indigenous hunters occasionally encountered the okapi while foraging, noting its long neck, reddish-brown coat, and striped hindquarters as camouflage aids in the low-light habitat, though direct sightings remained infrequent due to its solitary habits and acute sensory evasion tactics. By the late 19th century, fragmented reports from these Congolese communities filtered to European explorers navigating the , providing the first indirect Western glimpses without physical evidence. , during his 1887–1889 expedition, documented local narratives in his 1890 publication In Darkest Africa, where Wambutti informants described a "strange creature" resembling a donkey with zebra-like leg stripes, inhabiting remote tracts inaccessible to outsiders. These accounts highlighted the animal's rarity, as tribes reported it evading capture through swift, quiet movement and preference for swampy, vegetated refugia, yielding no skins or bones for verification at the time. The absence of specimens in early rumors stemmed from the okapi's low —estimated later at under 25,000 individuals across fragmented ranges—and the logistical barriers of the Ituri's tangled terrain, which limited even skilled indigenous trackers to sporadic encounters.

Western Scientific Discovery

British explorer Sir Harry Johnston initiated the Western scientific recognition of the okapi in late 1900 by acquiring two strips of okapi skin from Mbuti pygmies in the Congo, which he forwarded to zoologist Philip Lutley Sclater in for preliminary assessment. These samples, described as bearing zebra-like stripes on a horse-like hide, fueled early interest but lacked skeletal evidence for full verification. In March 1901, Johnston obtained a complete adult skin, an adult skull, and a smaller skull via Lieutenant Karl Eriksson from the Mbeni station in the Congo Free State, providing the tangible specimens necessary for taxonomic classification. These remains, procured indirectly from local hunters, were shipped to the British Museum for analysis, where their cloven hooves and giraffid dental structure contradicted initial assumptions of equine affinity. On June 18, 1901, E. Ray Lankester formally named the genus Okapia based on this material, with the species designated Okapia johnstoni in honor of Johnston's role. The okapi's chimeric morphology—combining giraffe-like patterns with zebra-esque leg stripes—elicited , with some naturalists suspecting a composite akin to the era's fabricated "" relics. This doubt persisted until comparative confirmed its position as a novel giraffid, distinct from equids, through metrics and details aligning more closely with giraffes than modern ungulates. Verification advanced with early 20th-century live captures; for instance, a one-month-old calf photographed by explorer Signor Ribotti circa 1907 offered the first visual evidence of a living specimen, corroborating field reports from missionaries in the Ituri Forest.

Taxonomy and Evolutionary Biology

Etymological Origins

The vernacular name "okapi" derives from indigenous Congolese terms, particularly the Mbuba okapi or the related Lese Karo o'api, as documented by British explorer during his 1900 expeditions in the Congo region. encountered reports and evidence of the animal from local hunters, incorporating the term into European accounts to describe the striped-legged forest previously unknown to science. The genus name Okapia, proposed by zoologist Philip Lutley Sclater, directly adapts this local nomenclature to reflect the animal's native linguistic identification, distinguishing it from giraffe-like traits observed in specimens. The specific johnstoni commemorates Johnston's role in procuring and publicizing the first , including skins shipped to in July 1900. Sclater formalized the binomial Okapia johnstoni in his 1901 publication in the Proceedings of the , initially considering equine affinities before settling on a giraffid based on anatomical review.

Systematic Classification

The okapi (Okapia johnstoni) belongs to the family , which comprises the giraffes and okapis as its only extant members, with the (Giraffa camelopardalis) the only other extant giraffid. This placement reflects cladistic analysis emphasizing shared derived traits such as a pacing and specialized , distinguishing Giraffidae from other families like . Higher in the hierarchy, the okapi is situated in the order Artiodactyla (even-toed ungulates), though integrates cetaceans into the inclusive clade Cetartiodactyla, underscoring the of and whales based on SINE retroposon insertions and genomic synteny. The genus Okapia, established by Lankester in 1901, is monotypic at the species level, with no additional congeners beyond O. johnstoni. Subspecies delineation is restricted to the nominate form O. johnstoni johnstoni, as range-wide phylogeographic studies reveal substantial —nucleotide diversity comparable to multi-subspecies taxa like giraffes—yet insufficient structured variation or diagnosable morphological clusters to warrant formal subspecific splits under phylogenetic species concepts. Classification relies on diagnostic morphological synapomorphies, including short ossicones (horn-like bony protuberances under skin, less than 15 cm long) present exclusively in males, with females exhibiting hair whorls in their stead, contrasting the ossicones in both sexes of giraffes. An elongated relative to body size, longer than in other non-giraffid ruminants but shorter than in giraffes, further supports giraffid affiliation via enhanced locomotor coordination in dense habitats.

Phylogenetic and Evolutionary History

The family, encompassing okapi and , originated during the early , with evidence indicating an initial radiation of adapted to wooded habitats across and . Earliest known giraffid remains, such as Canthumeryx sirtensis, date to approximately 20 million years ago from sites in and , featuring primitive morphologies with shorter limbs and suited to browsing softer vegetation in forested environments rather than the open grasslands that later dominated . This early diversification reflects causal pressures from expanding woodlands, where ancestral giraffids exploited understory foliage without the extreme cervical elongation seen in later savanna-adapted forms. Molecular clock analyses, calibrated via rates in whole-genome sequences, estimate the divergence of the okapi (Okapia johnstoni) lineage from the (Giraffa spp.) clade at 11.5 to 12 million years ago in the Middle . This split coincided with paleoenvironmental shifts, including the fragmentation of continuous forests and the emergence of more open habitats in eastern ; the okapi lineage specialized in persistent central African rainforests, favoring retention of ancestral traits like a compact (typically 30-50 cm long) for maneuvering through dense undergrowth and selective browsing on low terrestrial plants, whereas underwent iterative vertebral elongation to access arboreal resources in savannas. Fossil intermediates, such as Samotherium from late deposits (circa 7-8 million years ago), exhibit transitional neck proportions, underscoring the okapi's conservation of plesiomorphic features amid these habitat-driven divergences. Okapi phylogeny highlights niche conservatism, with mitochondrial and nuclear data revealing deep, stable lineages tied to refugia, contrasting the 's into arid zones. Primitive retentions—such as unfused metapodials, a prehensile for low foliage, and reduced ossicones—causally align with selective advantages in shaded, thorny understories, where elongated necks would impede mobility and increase predation risk from leopards, unlike the competitive high-browsing pressures shaping morphology. This evolutionary stasis underscores how stability preserved basal giraffid bauplans, as evidenced by minimal post-divergence morphological shifts in okapi fossils from Pliocene-Pleistocene deposits.

Physical Morphology and Adaptations

External Features

The okapi exhibits a slender build with a head-body of 1.9 to 2.5 meters, a of 30 to 42 cm, and a of 1.35 to 1.75 meters. Adult weights range from 180 to 356 kg, with males averaging heavier at 240 to 356 kg and females lighter at 180 to 260 kg. is limited, primarily manifesting in size differences and cranial features, though females may average slightly taller by 4.2 cm and possess a subtly redder coat hue. The pelage consists of a dark reddish-brown or coloration with a velvety, oily texture that sheds effectively. Black-and-white stripes mark the hindquarters, upper forelegs, and legs, contrasting the otherwise uniform body coat. Males bear short ossicones—- and -covered bony protuberances up to 15 cm long—while females exhibit hair whorls in equivalent positions atop the head. In comparison to the , its closest living relative, the okapi displays a proportionally shorter , smaller overall stature, and striped rather than spotted patterning on the limbs.

Internal Anatomy and Sensory Systems

The okapi possesses a prehensile measuring up to 45 cm in length, enabling it to strip leaves and browse vegetation selectively, a trait shared with its relative, the . This muscular organ, dark blue to black in coloration, facilitates grooming of its own eyes and ears due to its extensibility and dexterity. Internally, the okapi's digestive system is adapted for of fibrous plant material as a browsing . Its reticulorumen constitutes approximately 9.8% of body weight with relatively weak rumen pillars, supporting efficient microbial breakdown of cellulose-rich diets. Particle retention in the forestomach exceeds fluid retention, allowing prolonged of slow-degrading fibers, though less pronounced than in grazing like . Post-ruminal digestion occurs in the , where microbial and undigested dietary proteins are absorbed. Sensory adaptations emphasize non-visual cues suited to dense environments. The okapi exhibits acute hearing via large, mobile ears capable of detecting subtle sounds for predator avoidance. Olfaction is highly developed, aiding in and social recognition through scent marking with preorbital glands. Vision is comparatively reduced, with reliance on low-light capabilities from abundant rod cells in the rather than acute daylight acuity. Skeletally, the okapi's lack the extreme elongation seen in giraffes, featuring shorter, more robust structures that permit greater flexibility for maneuvering in undergrowth. The C7 vertebra in particular shows a unique realignment of the dorsal tubercle, contributing to enhanced mobility distinct from the giraffe's rigid configuration. This skeletal arrangement supports agile movement without the specialized adaptations of open-savanna giraffids.

Habitat and Geographic Distribution

Current Range and Historical Extent

The okapi (Okapia johnstoni) is endemic to the (DRC), with its current distribution confined to dense rainforest regions north and east of the . Primary populations occur in the Ituri Forest, with extensions into protected areas such as the Salonga National Park and Maiko National Park. GIS mapping and surveys conducted since the early 2000s confirm fragmentation of these populations by natural barriers like rivers and human-induced clearings, limiting and connectivity. Historical records indicate a broader extent prior to the , encompassing much of northern and central-eastern DRC and potentially extending into adjacent western . Early ethnographic accounts from indigenous groups and limited colonial-era collections suggest okapi were once more widely distributed across forested zones now altered by settlement and resource extraction, though precise pre-1900 boundaries remain unverified due to sparse documentation. No reliable current population estimate is available for the okapi in the wild, though ongoing declines are noted from historical rough guesstimates exceeding 30,000 individuals. No confirmed extralimital populations exist outside the DRC, despite occasional unverified reports from bordering regions.

Environmental Preferences and Adaptations

Okapis inhabit the dense of closed-canopy tropical rainforests at elevations ranging from 500 to 1,500 meters above sea level, primarily within the Ituri Forest and adjacent basins in the . These environments feature multilayered vegetation with emergent trees exceeding 30 meters in height, creating shaded, humid microclimates that align with the species' physiological needs for and low-light navigation, as evidenced by field observations and limited telemetry tracking. Okapis avoid open gallery forests along watercourses, preferring interiors with minimal disturbance to maintain . The composition is critical, dominated by thick herbaceous layers that provide cover from predators such as leopards; Marantaceae species contribute to this impenetrable growth, supporting the okapi's reliance on forested cores over 1 square kilometer for viable movement. Okapis also depend on licks, where they consume reddish clay or lick sulfurous soils to obtain sodium, calcium, and other trace elements scarce in their leafy diet, with field reports documenting regular visitation to such sites for geophagy. Altitudinal migration is rare or absent, with individuals exhibiting site fidelity within mid-elevation bands rather than seasonal elevational shifts, as indicated by patterns in long-term surveys. In fragmented habitats, okapis demonstrate heightened sensitivity to , including altered humidity, increased light penetration, and elevated predation risk, which degrade the dense cover essential for their survival and limit use of patches smaller than 100 square kilometers.

Behavioral Ecology

Activity Cycles and Foraging Strategies


Okapis display primarily diurnal activity patterns, with peaks in feeding activity during mid-morning and late afternoon, though they exhibit some crepuscular and nocturnal movements, particularly on moonlit nights. In human-disturbed habitats, increased nocturnal or crepuscular tendencies aid in evading threats. Individuals cover daily distances of 0.5 to 4 km along fixed feeding paths within their home ranges, optimizing resource acquisition while minimizing energy expenditure. Okapis are predominantly solitary, associating primarily with during early calf dependency, though occasional small feeding groups of up to three individuals have been observed in the wild. Territories are maintained through scent-marking via spraying (males often crossing legs), dung deposition at communal sites, tarsal secretions from the feet, and neck-rubbing on to deposit dermal . Males assert dominance through giraffe-like neck extensions, stretching the neck upward and forward to display stature during encounters. Foraging strategies emphasize selective browsing along established trails, leveraging acute hearing and olfactory cues to locate food while navigating dense . Anti-predator defenses prioritize over evasion, with reliance on disruptive striping for forest , prolonged freezing upon threat detection, and acute auditory sensitivity via large, rotatable ears to monitor and other predators. Vocalizations are rare but include alarm calls—described as barks or bleats—to alert kin, supplemented by defensive kicking if approached.

Dietary Habits

The okapi (Okapia johnstoni) maintains a highly selective browser diet dominated by foliage, consisting primarily of leaves from over 100 species, supplemented by fruits, seeds, ferns, and fungi. Fecal analyses confirm this composition, revealing a predominance of dicotyledonous woody with minimal inclusion of grasses or monocotyledons, though the latter may occur sporadically in forest clearings where light-dependent vegetation predominates. Daily dry matter intake in the wild averages 18–29 kilograms, reflecting efficient suited to nutrient-rich, low-fiber browse rather than bulk . To meet mineral requirements, okapis regularly consume geophagous materials such as reddish clay from riverbeds or sulfurous soils, which provide essential salts, alongside occasional bat guano for additional nutrients. This supplementation addresses potential deficiencies in the , as evidenced by direct observations and isotopic studies of forest soils. Dietary composition exhibits limited seasonal variation, attributable to the stable resource availability in equatorial rainforests, where persists year-round without pronounced fluctuations in productivity or . Fecal profiling from free-ranging populations supports this, showing consistent fiber and nutrient profiles across wet and dry periods.

Social Interactions and Communication

Okapis are predominantly solitary in the wild, spending about 90% of their time alone, with field observations indicating that groups rarely exceed three individuals, typically comprising a and . Social interactions are infrequent and brief, mainly limited to male-female encounters for , during which home ranges show minimal overlap between sexes. The primary sustained bond occurs between mothers and calves, who remain within the maternal home range for 2 to 6 months post-birth before achieving greater independence. Non-invasive genetic studies from the Réserve de Faune à Okapis in the of Congo confirm this solitary structure, revealing no close spatial associations among individuals and evidence of polygamous patterns. Communication primarily involves olfactory signals, with secretions from foot glands, , and dung used to mark territories and convey information. Males exhibit the to sample female , aiding assessment of estrus prior to . Vocalizations are rare outside specific contexts, consisting of chuffs for contact between individuals, moans by males during , bleats from calves under stress, and occasional whistles or bellows in acute distress; many include infrasonic components inaudible to humans. Males establish dominance through ritualized displays such as neck stretching, head tossing, and maintaining an erect posture, with subordinates lowering their heads; physical confrontations like charging or head-butting occur but are not the norm. These behaviors, documented in wild and captive observations, underscore a low level of consistent with the ' elusive, solitary , challenging prior notions of higher gregariousness derived from limited early sightings.

Reproductive Biology and Life History

Okapi exhibit a polygynous , in which individual males mate with multiple females over their lifetimes, though direct observations in the wild are limited due to the species' elusive . Females typically reach between 1 and 2 years of age, while males attain maturity later, around 2 to 3 years. Estrus cycles in females recur approximately every 15 days, with no strict breeding season observed, though births in both wild and captive populations peak from August to October, coinciding with seasonal rainfall patterns in their native habitat. Gestation lasts 440 to 450 days on average, ranging from 414 to 493 days in captive records, after which females give birth to a single calf, with twins occurring only rarely. Newborn calves weigh 14 to 30 kg and can stand within 30 minutes of birth, enabling rapid evasion of predators. In the wild, calf survival is low, estimated at around 50% during the first year primarily due to predation, contributing to the species' overall low . Interbirth intervals average 34 months in programs, potentially longer in the wild owing to environmental stressors and resource availability. Mothers wean calves at about 6 months, after which young remain dependent for extended periods, reflecting the species' K-selected reproductive strategy adapted to stable but predator-rich environments.

Conservation and Population Dynamics

Current Status and Population Data

The okapi (Okapia johnstoni) has been classified as Endangered on the since 2013, based on criteria indicating a reduction exceeding 50% over approximately three generations due to observed declines. No reliable current estimates exist for the total wild , owing to the ' elusive nature and challenges in surveying dense forest habitats. The trend is decreasing. In key protected areas such as the Okapi Wildlife Reserve—a UNESCO World Heritage site—local populations are monitored through methods including dung counts and camera traps, which have documented okapi presence but indicate low densities consistent with broader habitat constraints. Camera trap surveys conducted in the 2020s, including efforts in regions like Virunga National Park and the reserve, have captured images confirming ongoing occupancy, though quantitative density estimates vary and are typically below 1 individual per square kilometer due to methodological limitations in decay rates and detection probabilities. The Okapi Conservation Strategy 2015–2025 establishes benchmarks for population monitoring, emphasizing standardized surveys to track trends toward stability by 2025, with ongoing implementation involving camera traps and collaborative efforts as of 2025. These activities provide baseline data for future assessments, highlighting the need for refined estimation techniques to improve accuracy beyond historical dung-based extrapolations.

Anthropogenic Threats and Natural Risks

The okapi (Okapia johnstoni) faces severe anthropogenic threats primarily in its native Democratic Republic of Congo (DRC), where from , , and agricultural encroachment reduces available forest cover and isolates populations. These activities, often driven by economic pressures and weak enforcement, degrade the dense essential for the species' cover and foraging. Poaching for and skins compounds the pressure, with okapi hunted opportunistically by local communities and armed groups amid food scarcity. Ongoing civil unrest in eastern DRC exacerbates these issues, as armed militias and even state forces exploit governance vacuums to conduct illegal extraction and hunting, disrupting ranger patrols and enabling incursions into protected areas like the Okapi Wildlife Reserve. A stark example occurred on June 24, 2012, when bandits raided the Epulu station in the reserve, killing seven people—including guards—and slaughtering 14 captive okapi in apparent retaliation for efforts, underscoring how political instability directly imperils conservation infrastructure. Naturally, leopards (Panthera pardus) represent the main predator, preying chiefly on vulnerable calves due to the okapi's size and cryptic coloration deterring attacks on adults. This predation exerts selective pressure but pales against human impacts, as empirical assessments indicate hunters pose a far greater existential risk. The species' K-selected traits—such as a 15-month , single calf births every two years, and low population densities—further limit intrinsic resilience, slowing recovery from episodic losses. Disease outbreaks remain undocumented as a primary wild threat, though parasites and infections contribute to mortality in fragmented habitats.

Conservation Strategies and Interventions


The Okapi Wildlife Reserve, established by ministerial decree in 1992, serves as the primary area for the okapi, encompassing 13,700 km² of the Ituri Forest under the management of the Institut Congolais pour la Conservation de la Nature (ICCN). ICCN implements patrols focused on the reserve's 2,820 km² core zone and engages community programs to mitigate human-wildlife conflict and promote sustainable resource use, though coverage remains sporadic in peripheral areas due to logistical constraints and armed insecurity. These efforts have contributed to relative population stability within the reserve, contrasting with steeper declines outside protected zones where unregulated has destroyed habitats equivalent to over 1,920 hectares detected via . The ICCN's 2015-2025 Okapi Conservation Strategy prioritizes habitat connectivity through zoning and permanent staffing to link fragmented forest blocks, aiming for stable or increasing populations by 2025 via threat reduction and monitoring. Anti-poaching interventions incorporate technologies such as SMART (Spatial Monitoring and Reporting Tool) software to analyze patrol data and enhance ranger efficiency, alongside occasional drone surveillance for detecting incursions, though implementation in the okapi range lags behind more accessible . Transboundary cooperation addresses cross-border threats, including okapi product trafficking into , through joint monitoring proposed in regional frameworks, but formal agreements remain limited amid DRC-Uganda border tensions. Empirical outcomes reveal enforcement gaps: while core reserve populations exhibit stability from sustained patrols—evidenced by consistent fecal DNA and camera-trap detections—external declines exceed 50% over recent generations, driven by mining-induced habitat loss accounting for 98% of reductions since 2009. Over-reliance on international funding for ICCN operations has yielded mixed results, hampered by systemic corruption; in 2023, the U.S. sanctioned senior ICCN officials, including the former director-general, for facilitating wildlife trafficking and bribe-taking, which undermines aid effectiveness and local accountability. Such graft, prevalent in DRC conservation institutions, prioritizes elite capture over field outcomes, necessitating reforms like independent audits to bolster causal links between interventions and species recovery.

Ex Situ Management and Captive Populations

The global captive is managed through regional programs such as the European Endangered Species Programme (EEP) and the Association of Zoos and Aquariums (AZA) (SSP), with approximately 50 individuals in European zoos and a comparable number in North American institutions, totaling around 80-100 animals as of recent assessments. These programs track pedigrees via studbooks to promote breeding and maintain , though studies have documented substantial loss of in captive lineages despite these efforts. Breeding successes, such as over 70 births at the since 1962 and more than 33 calves raised at the , have helped stabilize captive numbers amid wild population declines. Captive okapi face welfare challenges, including high prevalence of stereotypies such as object (72.4% of individuals) and pacing (29.2%), often linked to environmental factors like barren enclosures and limited opportunities. Diet mismatches, where captive feeds fail to replicate the fibrous, browse-heavy wild intake, contribute to issues, while overall exceeds wild estimates, with individuals living 15-30 years in zoos compared to shorter spans in the wild due to predation and stressors. These abnormalities indicate suboptimal , as pacing correlates with restricted and lack of naturalistic stimuli. Studbook data supports pedigree analysis and breeding recommendations to mitigate , providing insights into that inform . However, reintroduction of captive-bred okapi remains limited and problematic, constrained by to human environments, risks to upon release, and the ' specialized needs, with few successful trials documented. Such efforts prioritize genetic rescue over routine supplementation of wild populations.

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