Wildebeest (, WIL-di-beest; , VIL-,), also called gnu (, NOO or , NEW), are antelopes of the genus Connochaetes and native to Eastern and Southern Africa. They belong to the family Bovidae, which includes true antelopes, cattle, goats, sheep, and other even-toed horned ungulates. There are two species of wildebeest: the black wildebeest or white-tailed gnu (C. gnou), and the blue wildebeest or brindled gnu (C. taurinus). Fossil records suggest these two species diverged about one million years ago, resulting in a northern and a southern species. The blue wildebeest remained in its original range and changed very little from the ancestral species, while the black wildebeest changed more as adaptation to its open grassland habitat in the south. The most obvious ways of telling the two species apart are the differences in their colouring and in the way their horns are oriented. In East Africa, the blue wildebeest is the most abundant big-game species; some populations perform an annual migration to new grazing grounds, but the black wildebeest is merely nomadic. Breeding in both takes place over a short period of time at the end of the rainy season and the calves are soon active and are able to move with the herd, a fact necessary for their survival. Nevertheless, some fall prey to large carnivores, especially the spotted hyena. Wildebeest often graze in mixed herds with zebras, which gives heightened awareness of potential predators. They are also alert to the warning signals emitted by other animals such as baboons. Wildebeest are a tourist attraction but compete with domesticated livestock for pasture and are sometimes blamed by farmers for transferring diseases and parasites to their cattle. Illegal hunting does take place but the population trend is fairly stable. Wildebeest can also be found in national parks or on private land. The International Union for Conservation of Nature lists both kinds of wildebeest as least-concern species.
Etymology Wildebeest is Dutch for 'wild beast', 'wild ox' or 'wild cattle' in Afrikaans (bees 'cattle'). The name was given by Dutch settlers who saw them on their way to the interior of South Africa in about 1700 because they resemble wild ox. The blue wildebeest was first known to westerners in the northern part of South Africa a century later, in the 1800s. Some sources claim the name gnu originates from the Khoekhoe name for these animals, t'gnu. Others contend the name and its pronunciation in English go back to the word !nu: used for the black wildebeest by the San people.
Classification
Taxonomy and evolution The genus name Connochaetes derives from the Ancient Greek words κόννος, kónnos 'beard', and χαίτη, khaítē 'flowing hair, mane'. It is placed under the family Bovidae and subfamily Alcelaphinae, where its closest relatives are the hartebeest (Alcelaphus spp.), the hirola (Beatragus hunteri), and species in the genus Damaliscus, such as the topi, the tsessebe, the blesbok and the bontebok. The name Connochaetes was given by German zoologist Hinrich Lichtenstein in 1812. In the early 20th century, one species of the wildebeest, C. albojubatus, was identified in eastern Africa. In 1914, two separate races of the wildebeest were introduced, namely Gorgon a. albojubatus ("Athi white-bearded wildebeest") and G. a. mearnsi ("Loita white-bearded wildebeest"). However, in 1939, the two were once again merged into a single race, Connochaetes taurinus albojubatus. In the mid-20th century, two separate forms were recognised, Gorgon taurinus hecki and G. t. albojubatus. Finally, two distinct types of wildebeest – the blue and black wildebeest – were identified. The blue wildebeest was at first placed under a separate genus, Gorgon, while the black wildebeest belonged to the genus Connochaetes. Today, they are united in the single genus Connochaetes, with the black wildebeest being named (C. gnou) and the blue wildebeest (C. taurinus). According to a mitochondrial DNA analysis, the black wildebeest are estimated to have diverged from the main lineage during the Middle Pleistocene and became a distinct species around a million years ago. A divergence rate around 2% has been calculated. The split does not seem to have been driven by competition for resources, but instead because each species adopted a different ecological niche and occupied a different trophic level. Blue wildebeest fossils dating back some 2.5 million years ago are common and widespread. They have been found in the fossil-bearing caves at the Cradle of Humankind north of Johannesburg. Elsewhere in South Africa, they are plentiful at such sites as Elandsfontein, Cornelia, and Florisbad. The earliest fossils of the black wildebeest were found in sedimentary rock in Cornelia in the Free State and dated back about 800,000 years. Today, five subspecies of the blue wildebeest are recognised, while the black wildebeest has no named subspecies.
Genetics and hybrids The diploid number of chromosomes in the 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. Other chromosomes were acrocentric. The X chromosome is a large acrocentric and the Y chromosome a minute one. The two species of the wildebeest are known to hybridise. Male black wildebeest have been reported to mate with female blue wildebeest and vice versa. The differences in social behaviour and habitats have historically prevented interspecific hybridisation between the species, but hybridisation may occur when they are both confined within the same area. The resulting offspring are usually fertile. A study of these hybrid animals at Spioenkop Dam Nature Reserve in South Africa revealed that many had disadvantageous abnormalities relating to their teeth, horns, and the wormian bones in the skull. Another study reported an increase in the size of the hybrid as compared to either of its parents. In some animals, the tympanic part of the temporal bone is highly deformed, and in others, the radius and ulna are fused.
Characteristics of the species
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