The blue wildebeest (Connochaetes taurinus), also called the common wildebeest, white-bearded wildebeest 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 colouration at the age of two 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 a herbivore, feeding primarily on the 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 eight and a half months. The calf remains with its mother for eight months, after which time 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. Each year, some East African populations of blue wildebeest take part in a long-distance migration, seemingly timed to coincide with local patterns of rainfall and grass growth.
The blue wildebeest is native to Angola, Botswana, Kenya, Mozambique, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe. Today it is extinct in Malawi, but has been successfully reintroduced in Namibia. The southern limit of the blue wildebeest range is the Orange River, while the western limit is bounded by Lake Victoria and Mt Kenya. The blue wildebeest is widespread and is being introduced into private game farms, reserves and conservancies. For this reason, the International Union for Conservation of Nature and Natural Resources (IUCN) rates the blue wildebeest as being of Least Concern. The population has been estimated to be around one and a half million and the population trend is stable.
The blue wildebeest was first described by English naturalist William John Burchell in 1823 and he 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 generic name Connochaetes derives from the Greek words κόννος, kónnos, "beard", and χαίτη, khaítē, "flowing hair", "mane". 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, while the alternative name "gnu" originates from the name for these animals used by the Khokloi people, a native pastoralist tribe of southwestern Africa.
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, it was found that the two had a close phylogenetic relationship and had diverged about a million years ago.
The blue wildebeest is known to hybridise with the black wildebeest. The differences in social behaviour and habitats have historically prevented interspecific hybridisation, however it may occur when both species are confined within the same area, and the offspring is 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 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 a million years ago, in the mid to late Pleistocene. Fossil evidence suggests that the 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.
The blue wildebeest exhibits sexual dimorphism, with males being larger and darker than females. The blue wildebeest is typically between 170–240 cm (67–94 in) in head-and-body length. The average height of the species is 115–145 cm (45–57 in). While males weigh up to 290 kg (640 lb), females seldom exceed 260 kg (570 lb). A characteristic feature is the long, black tail, which is around 60–100 cm (24–39 in) in length. All features and markings of this species are bilaterally symmetrical for both sexes. The average life span is 20 years in the wild, and 21 years in captivity. The oldest known captive individual lived for 24.3 years.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 colouration at the age of two months. The adults' hues range from a deep slate or bluish gray to light gray or even grayish-brown. The back and flanks are slightly lighter than the ventral surface and underparts. Dark brown vertical stripes mark the area between the neck and the back of the ribcage, 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 as well. While the manes of the western and eastern white-bearded wildebeest are lank, those of the Nyassaland wildebeest and common wildebeest stick up. Scent glands, which secrete a clear oil, are present in the forefeet and are larger in males than females.
In terms of skull length, the smallest subspecies of the blue wildebeest is the western white-bearded wildebeest. It is also the darkest subspecies, the eastern white-bearded wildebeest being the lightest race. Both these subspecies possess a creamy white beard, whereas the beard is black in both the Nyassaland wildebeest and the common wildebeest. The longest muzzles are found in the Nyassaland wildebeest, and the shortest in female western white-bearded wildebeest.