Blue wildebeest

Species of antelope

The blue wildebeest (Connochaetes taurinus), also called the common wildebeest, white bearded gnu or brindled gnu, is a large antelope and one of the two species of wildebeest. It is placed in the genus Connochaetes and family Bovidae, and has a close taxonomic relationship with the black wildebeest. The blue wildebeest is known to have five subspecies. This broad shouldered antelope has a muscular, front heavy appearance, with a distinctive, robust muzzle. Young blue wildebeest are born tawny brown, and begin to take on their adult coloration at the age of 2 months. The adults' hues range from a deep slate or bluish gray to light gray or even grayish brown. Both sexes possess a pair of large curved horns. The blue wildebeest is an herbivore, feeding primarily on short grasses. It forms herds which move about in loose aggregations, the animals being fast runners and extremely wary. The mating season begins at the end of the rainy season and a single calf is usually born after a gestational period of about 8.5 months. The calf remains with its mother for 8 months, after which it joins a juvenile herd. Blue wildebeest are found in short grass plains bordering bush covered acacia savannas in southern and eastern Africa, thriving in areas that are neither too wet nor too arid. Three African populations of blue wildebeest take part in a long distance migration, timed to coincide with the annual pattern of rainfall and grass growth on the short grass plains where they can find the nutrient rich forage necessary for lactation and calf growth. who gave it the scientific name Connochaetes taurinus. It shares the genus Connochaetes with the black wildebeest (C. gnou), and is placed in the family Bovidae, ruminant animals with cloven hooves. The specific name taurinus originates from the Greek word tauros, which means a bull or bullock. The common name "blue wildebeest" refers to the conspicuous, silvery blue sheen of the coat,

Though the blue and black wildebeest are currently classified in the same genus, the former was previously placed in a separate genus, Gorgon. In a study of the mitotic chromosomes and mtDNA, which was undertaken to understand more of the evolutionary relationships between the two species, the two were found to have a close phylogenetic relationship and had diverged about a million years ago.

C. taurinus has five subspecies:

C. t. taurinus (Burchell, 1823), the blue wildebeest, common wildebeest, or brindled gnu is found in southern Africa. Its range extends from Namibia and South Africa to Mozambique (north of the Orange River) and from southwestern Zambia (south of the Zambezi River) to southern Angola. C. t. johnstoni (Sclater, 1896), the Nyassaland wildebeest, occurs from Mozambique (north of the Zambezi River) to east central Tanzania. It is now extinct in Malawi. C. t. albojubatus (Thomas, 1912), the eastern white bearded wildebeest, is found in the Gregory Rift Valley (south of the equator). Its range extends from northern Tanzania to central Kenya. C. t. mearnsi (Heller, 1913), the western white bearded wildebeest, is found in northern Tanzania and southern Kenya. Its range extends from the west of the Gregory Rift Valley to Speke Bay on Lake Victoria. C. t. cooksoni (Blaine, 1914), Cookson's wildebeest, is restricted to the Luangwa Valley in Zambia. Sometimes, it may wander into the plateau region of central Malawi. In addition, the distinctive appearance of a western form, ranging from the Kalahari to central Zambia, suggests that subspecies mattosi (Blaine, 1825) may also prove distinct from subspecies taurinus. The western form can be recognised even at a distance by its upright mane, long beard, and minimal brindling.

The blue wildebeest is known to hybridise with the black wildebeest. The differences in social behaviour and habitats have historically prevented interspecific hybridisation, but it may occur when both species are confined within the same area, and the offspring are usually fertile. A study of these hybrid animals at Spioenkop Dam Nature Reserve in South Africa revealed that many had congenital abnormalities relating to their teeth, horns, and the Wormian bones of the skull. Another study reported an increase in the size of the hybrid as compared to either of its parents. In some hybrid animals, the auditory bullae are highly deformed, and in others, the radius and ulna are fused.

The diploid number of chromosomes in the blue wildebeest is 58. Chromosomes were studied in a male and a female wildebeest. In the female, all except a pair of very large submetacentric chromosomes were found to be acrocentric. Metaphases were studied in the male's chromosomes, and very large submetacentric chromosomes were found there as well, similar to those in the female both in size and morphology. The rest were acrocentric. The X chromosome is a large acrocentric, while the Y chromosome is a minute one. This species of wildebeest seems to have evolved around 2.5 million years ago. The black wildebeest is believed to have diverged from the blue wildebeest to become a distinct species around 1 million years ago, in the Middle to Late Pleistocene. Fossil evidence suggests that blue wildebeest were quite common in the Cradle of Humankind in the past. Apart from eastern Africa, fossils are commonly found in Elandsfontein, Cornelia, and Florisbad. Males typically weigh and females weigh A characteristic feature is the long, black tail, which is around in length. The average life span is 20 years in captivity. The oldest known captive individual lived for 24.3 years. They can travel up to in 5 days without drinking water, with average temperatures of in peak times of the day. thus giving it the name "brindled gnu". The manes of both sexes appear long, stiff, thick, and jet black, the same colour as the tail and face.

The blue wildebeest only has interdigital (hoof) glands in its fore legs. Analysis of chemical constituents from a free ranging animal in Zimbabwe (Cawston Block) showed this gland contains cyclohexanecarboxylic acid, phenol, 2 phenolethanol, and six short chain carboxylic acids.

The blue wildebeest is mostly active during the morning and the late afternoon, with the hottest hours of the day being spent in rest. These extremely agile and wary animals can run at speeds up to , waving their tails and tossing their heads. Bulls mark the boundaries of their territories with heaps of dung, secretions from their scent glands, and certain behaviors. Body language used by a territorial male includes standing with an erect posture, profuse ground pawing, and horning, frequent defecation, rolling and bellowing, and the sound "ga noo" being produced. When competing over territory, males grunt loudly, paw the ground, make thrusting motion with their horns, and perform other displays of aggression.

The blue wildebeest is a herbivore, feeding primarily on the short grasses which commonly grow on light, and alkaline soils that are found in savanna grasslands and on plains. Whenever possible, the wildebeest likes to drink twice daily Despite this, it can also survive in the arid Kalahari desert, where it obtains sufficient water from melons and water storing roots and tubers.

Male blue wildebeest become sexually mature at about 2 years of age, while females can conceive at 16 months if adequately nourished. During courtship, urination and low stretch are common activities, and the male soon attempts to mount the female. A receptive female holds her tail to one side and stands still while copulation takes place. Matings may be repeated several times and may take place twice or more times within a minute. The male neither eats nor rests when a female is present in his territory, and during this time, the female keeps close to the male, often rubbing her head on his torso and sniffing his penis. While in season, a female may visit several territories and mate with several different males. Although the causes of death vary from year to year, in one drought in Botswana, young calves and aged females were the most likely to die. On another occasion, an estimated 47% of deaths were caused by disease, 37% were due to predation, and the remainder were the result of accidents. Generally, the larvae of Gedoelstica and Oestrus occur in the nasal passages and respiratory cavities of the blue wildebeest, and sometimes migrate to the brain.

The blue wildebeest is native to Kenya, Tanzania, Botswana, Zambia, Zimbabwe, Mozambique, South Africa, Eswatini, and Angola. Today, it is extinct in Malawi, but has been successfully reintroduced into Namibia. The timing of the migration in both directions can vary considerably from year to year. At the end of the rainy season, they migrate to dry season areas in response to a lack of drinking water. When the rainy season begins again a few months later, the animals trek back to their wet season range. These movements and access to nutrient rich forage for reproduction allow migratory wildebeest populations to grow to much larger numbers than resident populations. Many long distance migratory populations of wildebeest existed 100 years ago, but currently, all but three migrations (Serengeti, Tarangire, and Kafue) have been disrupted, cut off, and lost.

Major human related factors affecting populations include large scale deforestation, the drying up of water sources, the expansion of settlements and poaching. Diseases of domestic cattle such as sleeping sickness can be transmitted to the animals and take their toll. Similarly, drastic declines have recently occurred in the Tarangire wildebeest migration. The total number of blue wildebeest is estimated to be around 100,000. The population trend overall is unstable and the numbers in the Serengeti National Park (Tanzania) have increased to about 1,300,000. The population density ranges from 0.15/km2 in Hwange and Etosha National Parks to 35/km2 in Ngorongoro Crater and Serengeti National Park, where they are most plentiful. Blue wildebeest have also been introduced into a number of private game farms, reserves, and conservancy areas. For these reasons, the International Union for Conservation of Nature rates the blue wildebeest as being of least concern. However, the numbers of the eastern white bearded wildebeest (C. t. albojubatus) have seen a steep decline to a current level of probably 6,000 to 8,000 animals, and this is causing some concern. However, blue wildebeest can also affect human beings negatively. They can compete with domestic livestock for grazing and water and can transmit fatal diseases like rinderpest to cattle and cause epidemics among animals. They can also spread ticks, lungworms, tapeworms, flies, and paramphistome flukes. An ancient carved slab of slate depicting an animal very similar to the blue wildebeest has been discovered. Dating back to around 3000 BC, it was found in Hierakonopolis (Nekhen), which used to be the religious and political capital of Upper Egypt at that time. This may be evidence that the animal used to occur in North Africa and was associated with the ancient Egyptians.