The okapi (Okapia johnstoni), also known as the forest giraffe, Congolese giraffe or zebra giraffe, is an artiodactyl mammal endemic to northeastern Democratic Republic of Congo in central Africa
Although the okapi has striped markings reminiscent of zebras, it is more closely related to the giraffe. The okapi and giraffe are the only living members of the family Giraffidae.
Physical characteristics of Okapis
The okapi is a medium-sized giraffid that stands 1.5 m tall at the shoulder. Its average body length is about 2.5 m and its weight ranges from 200 to 350 kg. In contrast to the white horizontal stripes on the white legs and ankles, the okapi’s coat is chocolate to reddish brown
The distinctive stripes resemble those of a zebra. These features serve as effective camouflage amid dense vegetation. The face, throat and chest are grayish white. Interdigital glands are present on all four legs, and are slightly larger on the front legs.
Male okapis have short, hair-covered structures called ossicones, measuring less than 15 cm (5. 24] The okapi exhibits sexual dimorphism: females are on average 4.2 cm taller, are slightly redder, and lack prominent ossicles; instead, they have coils of hair.
The okapi shows several adaptations to its tropical habitat. The large number of rod cells in the retina facilitates night vision, and an efficient olfactory system is present. The large auditory bullae of the temporal bone allow for a strong sense of hearing
The teeth are low-crowned with fine cusps, and effectively cut tender foliage. The large caecum and colon aid microbial digestion, and the rapid rate of passage of food allows less cell wall digestion than in other ruminants.
The okapi is easily distinguished from its closest relative, the giraffe. It is much smaller than the giraffe and shares more external similarities with bovids and cervids. The ossicones are only present in the male okapi, while both sexes of the giraffe possess this feature
It has large palatine sinuses (hollow cavities in the palate), unique among giraffids. Morphological traits shared by giraffe and okapi include a similar gait – both use a stepping gait, stepping simultaneously with the front and hind feet on the same side of the body, unlike other ungulates that walk by moving the feet alternately on each side of the body and a long black tongue (longer in okapi) useful for plucking shoots and leaves, as well as for grooming.
Behavior and feeding habits
Okapis are primarily diurnal, but may be active for a few hours in the dark They are essentially solitary and only gather to breed. Their ranges overlap and they usually have a density of about 0.6 animals per square kilometer
Males average 13 km2, while females average 3-5 km2. Males migrate continuously, while females are sedentary. They usually mark territories and bushes with their urine, while females use common defecation sites
Grooming is a common practice, centered on the earlobes and 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 his domain to forage for food. Males visit female territories during the breeding season
Although generally calm, the okapi may kick and head-butt to show aggression
As the vocal cords are poorly developed, vocal communication is mainly limited to three sounds: “chuff” (contact calls used by both sexes), “groan” (by females during courtship) and “bleat” (by young under stress). Individuals may emit the Flehmen response, a visual expression in which the animal curves back its upper lips, shows its teeth and inhales through its mouth for a few seconds. The leopard is the main natural predator of the okapi.
Okapis are herbivores and feed on leaves and shoots of trees, grasses, ferns, fruits and fungi. They are unique in the Ituri rainforest, as they are the only mammals known to feed solely on understory vegetation, where they use their 46 cm long tongue to selectively forage for suitable plants
They also use their tongues to groom their ears and eyes and prefer to feed in tree hollows. Okapi are known to feed on more than 100 species of plants, some of which are poisonous to humans and other animals
Where does the okapi live?
The okapi is endemic to the Democratic Republic of Congo, where it is found north and east of the Congo River. It is distributed from Maiko National Park to the north, to the Ituri forest, through the Ruby, Lake Tele and Ebola river basins 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.
The okapi inhabits treetops at an altitude of between 500 and 1,500 m (1,600-4,900 ft). It occasionally uses seasonally flooded areas, but is not found in gallery forests, swamp forests and habitats disturbed by human settlement. In the wet season, it visits rocky inselbergs that offer forage uncommon elsewhere
Reproductive process
Female okapis reach sexual maturity at one and a half years of age, while males reach sexual maturity at two years of age. Estrus in males and estrus in females does not depend on the season. In captivity, estrous cycles are repeated every 15 days.
The male and female begin courtship by circling, sniffing and licking each other. The male shows his interest by extending his neck, shaking his head and thrusting one leg forward. This is followed by mating and copulation.
The gestation period lasts between 440 and 450 days, after which a single calf weighing between 14 and 30 kg (31-66 lb) is usually born. The udder of the pregnant female begins to swell 2 months before parturition, and vulvar discharges may occur. Calving lasts 3 to 4 hours, and the female remains standing throughout this period, although she may rest for brief intervals. The mother consumes the placenta and grooms the calf. Her milk is very rich in protein and low in fat.
As in other ruminants, the calf can stand up 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 on the stripes. These features gradually disappear and give way to the general appearance after a year. Juveniles are kept hidden and lactation occurs infrequently
Hatchlings are known not to defecate during the first month or two of life, which is assumed to help avoid detection by predators in their most vulnerable phase of life.
The growth rate of hatchlings is appreciably high in the first few months of life, after which it gradually declines. Juveniles begin to take solid food at 3 months of age, and weaning takes place at 6 months. The development of the ossicon in males lasts 1 year after birth. The typical lifespan of the okapi is 20 to 30 years.
What dangers do okapis face?
The okapi is classified by the IUCN as endangered species and is fully protected under Congolese law. The Okapis Wildlife Reserve and Maiko National Park harbor important okapi populations, although their numbers have steadily declined due to various threats. Other areas of occurrence include the Rubi Tele Game Reserve and the Abumombanzi Reserve
The main threats are habitat loss due to logging and human settlement. Extensive hunting for bushmeat and skins and illegal mining have also led to population declines. A threat that has emerged very recently is the presence of illegal armed groups around the protected areas, which inhibits conservation and control actions
There is a small population north of Virunga National Park, but it lacks protection due to the presence of armed groups in the vicinity. In June 2012, a gang of poachers attacked the headquarters of the Okapis Wildlife Reserve, killing six guards and other staff, as well as the 14 okapis in its breeding center.
The Okapi Conservation Project, established in 1987, works for okapi conservation as well as the growth of the indigenous Mbuti people. In November 2011, White Oak Conservation Center and Jacksonville Zoo and Gardens hosted an international meeting of the Okapi Species Survival Plan and the European Okapi Endangered Species Program in Jacksonville, attended by representatives from zoos in the United States, Europe and Japan. The objective was to discuss the management of okapi in captivity and to organize support for okapi conservation. Many zoos in North America and Europe currently have okapis in captivity.
