Both at the Prague Zoo, Czech Republic
The Nile lechwe or Mrs Gray's lechwe (Kobus megaceros) is an endangered species of antelope found in swamps and grasslands in Sudan and Ethiopia. 
Males are an average of 165 cm (65 in) long and 100–105 cm (39–41 in) tall at the shoulders, and weigh between 90 and 120 kg (200 and 260 lb), while females are an average of 135 cm (53 in) long, 80–85 cm (31–33 in) tall at the shoulders, and weigh 60–90 kg (130–200 lb). Nile lechwes live an average of 10 to 11.5 years, and most uncommonly 19 years. 
Their coats are shaggy with the hair on the cheeks particularly long in both sexes, and males may have even longer hair on their necks. Nile lechwe exhibit extreme sexual dimorphism.  Females are golden-brown with white underbellies and no horns. Juveniles also have a golden-brown coat, but the color changes to dark brown in young males when they reach two to three years of age. Adult males are blackish-brown to russet with white 'hoods' over their shoulders and small white patches over their eyes.   The horns of the adult males are 50–87 cm (20–34 in) long, strongly ridged at their bases and are curved at the tips. 
Nile lechwe can visually signal and vocalize to communicate with each other. They rear high in the air in front of their opponents and turn their heads to the side while displaying. Females are quite loud, making a toad-like croaking when moving.  When fighting, males duck their heads and use their horns to push against each other. If one male is significantly smaller than the other, he may move next to the larger male in a parallel position and push from there, which prevents the larger male from pushing with all his force. Known predators are humans, lions, crocodiles, cheetahs, wild dogs and leopards. They flee to water if disturbed, but females defend their offspring from smaller predators by direct attack, mainly kicking.  Yearling Nile lechwes are often infected by warble flies, which can make them unhealthy and result in high mortality rates. 
Nile lechwe are crepuscular, active in the early morning and late afternoon. They gather in herds of up to 50 females and one male or in smaller all-male herds. They divide themselves into three social groups: females and their new offspring, bachelor males, and mature males with territories. A males with territory sometimes allows a bachelor male into his territory to guard the region and not to copulate. 
Nile lechwe feed on succulent grasses and water plants. Wild rice is thought to be a preferred food at the start of the flood season, while a larger proportion of swamp grasses are consumed when the waters recede. They have the special capability to wade in shallow waters and swim in deeper waters, and may feed on young leaves from trees and bushes, rearing up to reach this green vegetation. Nile lechwe are also found in marshy areas, where they eat aquatic plants. 
Both sexes reach sexual maturity when they are two years old.  Mating occurs throughout the year, but peaks between February and May. During mating season, young males bend their horns to the ground as if to poke the earth. Males fight in the water, their heads submerging in horn-to-horn combat, for dominance. These contests are usually short and violent. As in many other animals, the dominant male copulates with the female. A unique form of marking is seen with the start of mating. The male bends his head to the ground and urinates on his throat and cheek hair. He then rubs his dripping beard on the female's forehead and rump.  
The gestation period is seven to 9 months long on average, after which a single calf is born. Infants weigh about 4.5 to 5.5 kg (9.9–12.1 lb). Females experience estrus again about a month after producing young. After its birth, the calf is kept hidden in thick vegetation for two to three weeks, where the mother nurses it. It is weaned at five to six months, and a few months later is ready to be independent and join the herd. 
The Nile lechwe typically occur in shallow waters bordering deeper swamps, where the water is 10–40 cm (3.9–15.7 in) deep.  Nile lechwe are endemic to Sudan and Ethiopia. In Sudan, the majority of the population occurs in the Sudd swamps, and in the Machars near the Ethiopian border in smaller numbers. In Ethiopia occurs in the southwest, in Gambela National Park, but in very less numbers possibly due to human settlement and habitat degradation. The habitat of the Nile lechwe has been severely affected by civil wars, human displacement and resettlement, firearm attacks and increased hunting.  Even its seasonal movements were restricted due to large populations of cattle in and around its range. The Nile lechwe population in the Sudds, however, remained somewhat stable throughout this period. 
The Nile lechwe has been classified under the Endangered category by the International Union for Conservation of Nature and Natural Resources (IUCN). In 1983, aerial surveys gave a total population estimate of 30,000-40,000 individuals, of which 95 percent were concentrated in the Sudds and the rest occurred between Sudan and Ethiopia.  In the 1980s, the population in the Machars was estimated at 900.  A population of around 150 was also reported from the swamps in Gilo River in 1967.  There is also an increasing population held in captivity.  In 2007, the population of the Sudd region was estimated to be of 4,291 animals, indicating that the species has declined rapidly since the previous survey in 1983.
In South Sudan, Nile lechwe populations occur in three protected areas : Zeraf Game Reserve, that extends over 9,700 km2 (3,700 sq mi) along the Bahr el Zeraf; Fanyikang Game Reserve, north of Bahr el Ghazal, covering over 480 km2 (190 sq mi); and Shambe National Park, that stretches over 620 km2 (240 sq mi) along Bahr al Jabal. The Nile lechwe keep moving in and out of these areas. In Ethiopia they occur in the Gabella National Park. A study outlined priorities for both in situ and ex situ conservation of this species. 
The Sudd is a vast swamp in South Sudan, formed by the White Nile's Baḥr al-Jabal section. The Arabic word sudd is derived from sadd, meaning "barrier" or "obstruction". The term "the sudd" has come to refer to any large solid floating vegetation island or mat. The area which the swamp covers is one of the world's largest wetlands and the largest freshwater wetland in the Nile Basin.
The klipspringer is a small antelope found in eastern and southern Africa. The sole member of its genus and subfamily/tribe, the klipspringer was first described by German zoologist Eberhard August Wilhelm von Zimmermann in 1783. The klipspringer is a small, sturdy antelope; it reaches 43–60 centimetres at the shoulder and weighs from 8 to 18 kilograms. The coat of the klipspringer, yellowish gray to reddish brown, acts as an efficient camouflage in its rocky habitat. Unlike most other antelopes, the klipspringer has a thick and coarse coat with hollow, brittle hairs. The horns, short and spiky, typically measure 7.5–9 cm.
The addax, also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus Addax, it was first described scientifically by Henri de Blainville in 1816. As suggested by its alternative name, the pale antelope has long, twisted horns – typically 55 to 80 cm in females and 70 to 85 cm in males. Males stand from 105 to 115 cm at the shoulder, with females at 95 to 110 cm. They are sexually dimorphic, as the females are smaller than the males. The colour of the coat depends on the season – in the winter, it is greyish-brown with white hindquarters and legs, and long, brown hair on the head, neck, and shoulders; in the summer, the coat turns almost completely white or sandy blonde.
The sitatunga, sometimes called the marshbuck, is a swamp-dwelling medium-sized antelope found throughout central Africa, centering on the Democratic Republic of the Congo, the Republic of the Congo, Cameroon, parts of Southern Sudan, Equatorial Guinea, Burundi, Ghana, Botswana, Rwanda, Zambia, Gabon, the Central African Republic, Tanzania, Uganda and Kenya. The sitatunga is mostly confined to swampy and marshy habitats. Here they occur in tall and dense vegetation as well as seasonal swamps, marshy clearings in forests, riparian thickets and mangrove swamps.
The greater kudu is a large woodland antelope, found throughout eastern and southern Africa. Despite occupying such widespread territory, they are sparsely populated in most areas due to declining habitat, deforestation, and poaching. The greater kudu is one of two species commonly known as kudu, the other being the lesser kudu, T. imberbis.
The roan antelope is a large savanna-dwelling antelope found in western, central, and southern Africa. Named for its roan colour, it has lighter underbellies, white eyebrows and cheeks and black faces, lighter in females. It has short, erect manes, very light beards and prominent red nostrils. It is one of the largest antelope, measuring 190–240 cm (75–94 in) from head to the base of the tail, and a 37–48 cm (15–19 in) long tail. Males weigh 242–300 kg (534–661 lb) and females 223–280 kg (492–617 lb). Its shoulder height is around 130–140 cm (51–55 in).
The hartebeest, also known as kongoni or kaama, is an African antelope. It is the only member of the genus Alcelaphus. Eight subspecies have been described, including two sometimes considered to be independent species. A large antelope, the hartebeest stands just over 1 m at the shoulder, and has a typical head-and-body length of 200 to 250 cm. The weight ranges from 100 to 200 kg. It has a particularly elongated forehead and oddly-shaped horns, a short neck, and pointed ears. Its legs, which often have black markings, are unusually long. The coat is generally short and shiny. Coat colour varies by the subspecies, from the sandy brown of the western hartebeest to the chocolate brown of the Swayne's hartebeest. Both sexes of all subspecies have horns, with those of females being more slender. Horns can reach lengths of 45–70 cm (18–28 in). Apart from its long face, the large chest and the sharply sloping back differentiate the hartebeest from other antelopes. A conspicuous hump over the shoulders is due to the long dorsal processes of the vertebrae in this region.
The kob is an antelope found across Central Africa and parts of West Africa and East Africa. Together with the closely related reedbucks, waterbucks, lechwe, Nile lechwe, and puku, it forms the Reduncinae tribe. Found along the northern savanna, it is often seen in Murchison Falls and Queen Elizabeth National Park, Uganda; Garamba and Virunga National Park, and the Democratic Republic of the Congo, as well as grassy floodplains of South Sudan. Kob are found in wet areas, where they eat grasses. Kob are diurnal, but inactive during the heat of the day. They live in groups of either females and calves or just males. These groups generally range from five to 40 animals.
The lechwe, red lechwe, or southern lechwe is an antelope found in wetlands of south-central Africa.
The waterbuck is a large antelope found widely in sub-Saharan Africa. It is placed in the genus Kobus of the family Bovidae. It was first described by Irish naturalist William Ogilby in 1833. Its 13 subspecies are grouped under two varieties: the common or ellipsiprymnus waterbuck and the defassa waterbuck. The head-and-body length is typically between 177 and 235 cm and the typical height is between 120 and 136 cm. In this sexually dimorphic antelope, males are taller and heavier than females. Males reach roughly 127 cm (50 in) at the shoulder, while females reach 119 cm (47 in). Males typically weigh 198–262 kg (437–578 lb) and females 161–214 kg (355–472 lb). Their coat colour varies from brown to grey. The long, spiral horns, present only on males, curve backward, then forward, and are 55–99 cm (22–39 in) long.
The puku is a medium-sized antelope found in wet grasslands in southern Democratic Republic of Congo, Namibia, Tanzania, Zambia and more concentrated in the Okavango Delta in Botswana. Nearly one-third of all puku are found in protected areas, zoos, and national parks due to their diminishing habitat.
The bohor reedbuck is an antelope native to central Africa. The animal is placed under the genus Redunca and in the family Bovidae. It was first described by German zoologist and botanist Peter Simon Pallas in 1767. The bohor reedbuck has five subspecies. The head-and-body length of this medium-sized antelope is typically between 100–135 cm (39–53 in). Males reach approximately 75–89 cm (30–35 in) at the shoulder, while females reach 69–76 cm (27–30 in). Males typically weigh 43–65 kg (95–143 lb) and females 35–45 kg (77–99 lb). This sturdily built antelope has a yellow to grayish brown coat. Only the males possess horns which measure about 25–35 cm (9.8–13.8 in) long.
The West Caucasian tur is a mountain-dwelling goat-antelope native to the western half of the Caucasus Mountains range, in Georgia and European Russia. It is listed as Endangered on the IUCN Red List, as the wild population is estimated to be between 5,000 and 6,000 individuals.
The dibatag, or Clarke's gazelle, is a medium-sized slender antelope native to Ethiopia and Somalia. Though not a true gazelle, it is similarly marked, with long legs and neck. It is often confused with the gerenuk due to their striking resemblance. The typical head-and-body length is about 103 to 117 cm. They stand up to about 80 to 90 cm. Male dibatag weigh between 20 and 35 kg, whereas females range from 22 and 29 kg. The length of the curved horns, present only on males, is typically between 10 and 25 cm. The upper parts are gray to fawn, while the dorsal and lateral areas are cinnamon to rufous. The underparts, rump and the insides of the legs are all white. While markings are visible on the face, there are none on the flanks or the buttocks.
The Ugandan kob is a subspecies of the kob, a type of antelope. It is found in sub-Saharan Africa in South Sudan, Uganda and the Democratic Republic of the Congo. The Ugandan kob is normally reddish-brown, differentiating it from other kob subspecies.
The Upemba lechwe is a subspecies of antelope found only in the Upemba wetlands in the Democratic Republic of Congo. It was described in 2005, after analysis of 35 museum specimens collected in 1926 and 1947–8. Some authorities treat the Upemba lechwe as a species, K. anselli.
The Bahr el Zeraf, or Zeraf River in the English language, is an arm of the White Nile in the Sudd region of South Sudan. It is completely contained within the South Sudanese state of Jonglei. Its name is Arabic for "Giraffe River".
The Mongalla gazelle is a species of gazelle found in the floodplain and savanna of South Sudan. It was first described by British zoologist Walter Rothschild in 1903. The taxonomic status of the Mongalla gazelle is widely disputed. While some authorities consider it a full-fledged monotypic species in the genus Eudorcas, it is often considered a subspecies of Thomson's gazelle, while other authorities regard it as subspecies of the red-fronted gazelle.
Ez Zeraf Game Reserve is a 675,000-hectare (1,670,000-acre) protected area in northern South Sudan. It was designated in 1939 when the area was within Sudan.
Heuglin's gazelle, also known as the Eritrean gazelle, is a species of gazelle found east of the Nile River in Eritrea, Ethiopia and Sudan. It was considered a subspecies of the red-fronted gazelle or conspecific with Thomson's gazelle and Mongalla gazelle by some authors in the past. This small gazelle stands nearly 67 cm (26 in) at the shoulder and weighs between 15 and 35 kg. The coat is dark reddish brown with a dark reddish stripe on the flanks, except for the underparts and the rump which are white. Horns, present in both sexes, measure 15 to 35 cm in length.