Blue Wildebeest – Taxonomy, Evolution, Ecology and More

Blue Wildebeest – Taxonomy, Evolution, Ecology and More

The Blue wildebeest (scientific name: Connochaetes taurinus) is a big antelope that is one of two existing wildebeest species. It is also known as the white-bearded wildebeest, common wildebeest, brindled gnu, or white-bearded gnu. It belongs to the Connochaetes genus and the Bovidae family, and taxonomically, it is closely related to the black wildebeest. There are five known subspecies of the blue wildebeest. Blue wildebeests have a unique, powerful snout. This broad-shouldered antelope has a front-heavy, muscular look. Blue wildebeest are tawny brown at birth and develop their adult colour at two months of age. The colours of the adults range from a bluish-grey or deep slate to a light grey or greyish-brown. A pair of big curving horns are present on both sexes.

Blue wildebeest are mostly herbivores that feed on short grass. They create herds that roam in loose aggregations, with the animals being quick runners and watchful. The mating season starts at the conclusion of the rainy season, and they normally deliver one calf after an 8.5-month gestation period. The calf stays with its mother for eight months before joining a juvenile herd. Short-grass plains that border acacia savannas covered with bushes in eastern and southern Africa are home to blue wildebeest, which thrive in settings that are not too arid or too wet. Three populations of the blue wildebeest in Africa migrate considerable distances, in patterns that coincide with the yearly cycle of grass growth and rainfall on short-grass plains, where they find the fodder rich in nutrients required for calf growth and lactation.

The native habitats for blue wild beasts are Angola, Kenya, Botswana, Mozambique, Swaziland, South Africa, Tanzania, Zimbabwe and Zambia. They are now extinct in Malawi, but Namibia has successfully reintroduced them. The Orange River forms the southern edge of the range of the blue wildebeest, while Mount Kenya and Lake Victoria form the western border. Blue wildebeest are a common sight and are being introduced to private game ranches, parks, and conservancies. As a result, the blue wildebeest is considered the least concerning by the International Union for Conservation of Natural Resources and Nature. The population is approximately 1.5 million people, with a constant demographic trend.

Taxonomy and Nomenclature

Blue wildebeests were originally described in 1823 by John William Burchell, an English naturalist, who named them Connochaetes taurinus. It belongs to the Bovidae family, which includes ruminants with cloven hooves, and shares the Connochaetes genus with black wildebeests (C. gnou). The name Connochates is derived from the Greek names κόννος , kónnos, meaning “beard,” and, χαίτη, khaítē, meaning “mane” or “flowing hair,” from the genus name Connochaetes. Taurinus gets its name from tauros, a Greek word meaning “bullock” or “bull”. The popular term “blue wildebeest” refers to the coat’s distinctive silvery-blue shine, while the alternate name “gnu” comes from the Khoikhoi people, a traditional pastoralist population of southwest Africa, who used this name for them.

John William Burchell, an English naturalist
John William Burchell, an English naturalist

The black and blue wildebeests are now classed in the same genus, while the former was initially classified in its own genus, Gorgon. The two species were discovered to have a tight phylogenetic relationship and diverged approximately one million years ago, according to a study of mtDNA and mitotic chromosomes conducted to learn more about their evolutionary links.

Subspecies

There are five subspecies of C. taurinus:

  • t. taurinus, the blue wildebeest, sometimes known as the brindled gnu or common wildebeest, is widespread in southern Africa (Burchell, 1823). Its range is from South Africa and Namibia to Mozambique (to the north of River Orange) and from southwest Zambia (to the south of Zambezi River) to southern Angola.
  • t. johnstoni (identified by Sclater, 1896), known as the Nyassaland wildebeest, is found from Mozambique (to the north of Zambezi River) to central and eastern Tanzania. In Malawi, it is now extinct.
  • t. albojubatus (identified by Thomas, 1912), known as the eastern white-bearded wildebeest, is located in the Gregory Rift Valley (south of the equator). Its habitat ranges from north of Tanzania to central Kenya.
  • t. mearnsi (identified by Heller, 1913), also known as western white-bearded wildebeests, are found in southern Kenya and north of Tanzania. Its range stretches from the Gregory Rift Valley to Lake Victoria’s Speke Bay.
  • t. cooksoni (identified by Blaine, 1914), known as Cookson’s wildebeest, is only found in Zambia’s Luangwa Valley. It is known to occasionally travel into central Malawi’s plateau region.

Furthermore, the presence of a western variety that ranges from the Kalahari Desert to central Zambia shows that the mattosi subspecies (Blaine, 1825) is separate from the taurinus subspecies. The upright mane, lengthy beard, and modest brindling distinguish the western variety even from afar.

Hybrids

The black wildebeest and the blue wildebeest have been observed to hybridize. Interspecific hybridization has previously been prohibited due to differences in habitats and social behaviour, but it can happen when the species are confined within the same region, and usually, the offspring are viable. Many of the hybrid animals studied in South Africa’s Spioenkop Dam Nature Reserve exhibited congenital deformities involving their horns, teeth, and the skull’s Wormian bones. According to another study, the hybrid’s size increased in comparison to any of its parents. The auditory bullae of certain hybrid animals are severely malformed, while the ulna and radius of others are fused.

Evolution and Genetics

The blue wildebeest has 58 diploid chromosomes. The chromosomes of a female and a male wildebeest were examined. Except for a pair of extremely big submetacentric chromosomes, all of the female’s chromosomes were discovered to be acrocentric. The male chromosomes were examined for metaphases, and extremely big submetacentric chromosomes were also discovered, which were comparable in morphology and size to those found in their female counterpart. The remainder of the group was acrocentric. The X chromosome is a big acrocentric chromosome, whereas the Y chromosome is a small acrocentric chromosome.

This wildebeest species appears to have developed around 2.5m years ago. Around a million years ago, between the Middle and Late Pleistocene, they split to form a separate species. Blue wildebeest were formerly fairly numerous in the Cradle of Humankind, according to fossil evidence. Other than Eastern Africa, fossils are widely discovered at Elandsfontein, Florisbad and Cornelia.

Description

Males of the blue wildebeest are darker and larger than females, indicating sexual dimorphism. The length of the head and body is usually 170 to 240 cm (67 to 94 in). The species’ average height is 115 to 145 cm (45 to 57 in). Males weigh between 165 and 290 kg (364 and 639 lb), while females weigh between 140 and 260 kg (310 to 570 lb). The black, long tail, which measures 60 to 100 cm (24 to 39 inches) in length, is a distinguishing trait. For both sexes of this species, the characteristics and markings are bilaterally symmetrical. In the wild, the lifespan averages 20 years, while in captivity, it averages 21 years. The oldest captive wildebeest survived for a total of 24.3 years.

Colouration

The broad-shouldered wildebeest has a front-heavy, muscular, look and a characteristic robust muzzle. Young ones are tawny brown at birth, and when they are around two months old, they begin to develop their adult colour. The colours of the adults range from a bluish-grey or light grey to a greyish-brown or light grey. The underparts and ventral area are somewhat lighter compared to the flanks and back. The region between the neck and the rear of the ribs is marked by vertical, dark brown stripes, earning it the nickname “brindled gnu.” Both sexes have long, rigid, thick manes that are jet black, matching the face and tail. The eastern and western white-bearded wildebeest have lank manes, whereas those of common wildebeests and Nyassaland wildebeests typically stick up. Scent glands are found in the front feet and are bigger in males compared to females. They usually emit transparent oil.

The western white-bearded wildebeests are the blue wildebeest’s smallest species in respect to skull length. They are also the darkest subspecies; the lightest race is the eastern white-bearded wildebeest. Both subspecies have creamy white beards, but the common and Nyassaland wildebeests have black beards. Nyassaland wildebeest have the longest muzzles, whereas female western white-bearded wildebeest have the shortest.

Horns

A pair of enormous horns, formed like parenthesis, are seen on both sexes. This curls inward and upward after extending outward to the sides. Males’ horns can grow to be 83 centimetres (33 in) long, while females’ horns are 30 to 40 centimetres (12 to 16 inches) long. The blue wildebeest, while being an antelope, has a number of bovine features. The horns, for example, resemble a female African buffalo’s horns. It also has a bovine look due to its massive body and excessively huge forequarters.

Behaviour and Ecology

The blue wildebeest is most active in the morning and late afternoon, sleeping during the warmest hours of the day. These incredibly nimble and cautious creatures can reach speeds of 50mph (80 km/h). According to a study on blue wildebeest activities in the Serengeti National Park, the animals spent almost half of their time resting, 33% grazing, 12 per cent moving around (mainly walking), and a little amount of time socializing. However, there were differences across sex and age groups.

Wildebeests tend to congregate in loose groups and rest near each other. Males group in bachelor herds, which are distinguishable from the juvenile groups mostly by lower levels of activity as well as the spacing of the animals. Before the following mating season, almost 90 per cent of all the male calves form bachelor herds. Bulls become territorial and quite vociferous (especially in the western white-bearded wildebeest). The bulls can tolerate being in close proximity to one another, and one sq km (0.39 sq mi) of plain may hold 270 bulls. The majority of territories are ephemeral, and only around half of the bulls have permanent territories. At night, blue wildebeest generally rest in groups ranging from small to thousands, with a minimum spacing between individuals of 1 to 2 m (3 to 7 ft) (though calves and mothers can remain together). The main predators are lions, leopards, cheetahs, African wild dogs, crocodiles, and hyenas.

Female calves spend their whole lives with their mothers and related females in the herd. A herd’s female members range in age from yearlings up to the eldest cow. During the rainy season, the females usually direct the herd to grassy places that are rich in nutrients and away from predators. This is to give newborn calves have the best chance of surviving and receiving the best possible nutritious milk.

Bulls use dung piles, scent gland secretions, and specific behaviours to mark the borders of their territory. Territorial male body language includes copious ground pawing, standing with an upright posture, and horning, frequent defecation, rolling and bellowing, frequent defecation and the “ga-noo”. Males loudly grunt, paw the ground, move their horns in a thrusting manner, and make other aggressive gestures when contending for territory.

Diet

Blue wildebeests are herbivores that feed mostly on short grasses that thrive in alkaline, light soils found on plains and savanna grasslands. The broad mouth of the animal is designed to devour vast amounts of short grass. They feed both at night and in daylight. They can consume the leaves of bushes and trees if the grass is limited. Plains zebras and wildebeest are often seen together because the former eats the less nutritious, higher grass canopy, revealing the lower, greener stuff that wildebeest like. The wildebeest prefer to drink water twice a day whenever possible, and because of their constant need for water, it prefers to live in wet grasslands and locations with readily available sources of water. Every one or two days, the blue wildebeests drink between 9 and 12l of water. Despite this, they can still thrive in the dry Kalahari Desert, where water-storing roots and tubers and melons provide enough water.

The wildebeest were discovered to feed on three prominent types of grass in the region, namely Themeda triandra, Pennisetum mezianum, and Digitaria macroblephara, in research of their nutritional preferences. In the dry season, the amount of time spent grazing rose by roughly 100 per cent. The animals were more discriminating during the rainy season, even though their diet choices were similar in both the dry and wet seasons.

Reproduction

Male blue wildebeests reach sexual maturity at the age of two, while females are able to conceive as early as 16 months if well-fed. Despite this, most females don’t begin to reproduce for another year. The conclusion of the wet season corresponds with the mating season, which lasts around three weeks. This indicates that they are in good health, having fed on nutrient-dense fresh grass growth, and the rate of conception is typically high, about 95%. The rut, or mating season, usually begins on the full moon night, implying that the lunar cycle has an impact on reproduction. Male testosterone production peaks at this period, leading to heightened territorial activity and calling. The acts of sexually ecstatic males may induce estrus in the female.

Males show competition for females as they choose their territory. They confront one other while bending their knees and thrust their horns at each other while they fight. During their competition, they may snort, bellow and thrust their horns violently into the ground in individual displays. Following the establishment of dominance, each male strives to entice the female to his realm. Low stretch and urination are prevalent during courting, and then the male quickly tries to mount onto the female. While copulation is taking place, a consenting female stands still and holds its tail to the side. Matings can happen several times in a minute, and they can happen twice or more. When a female visits his domain, the male does not eat or sleep, and the female stays close to him throughout this period, rubbing her head on the male’s chest often and sniffing its penis. During mating season, a female can visit many territories and copulate with a variety of males.

The gestation lasts around 8.5 months, and 80 to 90% of the calves are delivered within three weeks. Female wildebeest often give birth at midday, in the centre of the herd instead of doing so alone. This gives the newborn enough time to get its bearings before darkness falls and brings the predators with it. Calves are born weighing around 42lb (19 kg) and can normally stand independently within some minutes. Calves stay near their mothers for a long time to avoid predators, and they may continue to suckle until the calf for the following year is almost due. Around the age of eight months, male calves leave their mothers and establish herds with fellow male juveniles. Compared to a 50% survival rate in smaller herds, 80 per cent of wildebeest progeny survive the 1st month in big female herds compared to the 50 per cent survival rate in tinier herds.

Parasites and Diseases

Blue wildebeests are vulnerable to anthrax, Foot-and-mouth disease, hoof gangrene, sarcoptic mange, and hoof gangrene. Walter Plowright, a veterinary scientist, first discovered the herpes virus from these animals in 1960. Although the fatality causes change from yearly, elderly females and young calves were most likely to perish as observed in Botswana during drought. In another instance, sickness was predicted to be responsible for 47 per cent of deaths, predation for 37%, and accidents for the remaining 5%.

They can be infected with a variety of parasites. In one research, blue wildebeest were discovered to host one trematode, 13 nematode species, 5 oestrid fly larvae, 3 lice species, 7 ixodid tick species, one mite, and a tongue worm larvae. Most of these were more common at certain periods of the year compared to others. Oestrus and Gedoelstica larvae are found in the blue wildebeest’s nasal passages and respiratory cavities and occasionally move to the brain. In comparison to other bovids, they are resistant to tick infections from a variety of species.

Habitat and Distribution

Kenya, Botswana, Tanzania, Zambia, Mozambique, Zimbabwe, South Africa, Zambia, Angola and Swaziland are home to blue wildebeests. In Malaya, it is extinct while in Namibia, it has successfully been reintroduced.

Blue wildebeests prefer short-grassed plains bordering acacia savannas covered by bushes in eastern and southern Africa, where they thrive in conditions that are not too wet or too dry. They live in a variety of environments, from overgrazed places with dense bushes to floodplains that are open wooded. In these locations, trees like Combretum and Brachystegia spp. are prevalent. Blue wildebeests can survive in desert areas as long as there is access to potable water, which is usually within 15km to–25 kilometres (9.3 mi and 15.5 miles). The Orange River marks the southern border of their range, while Mount Kenya and Lake Victoria mark the western border. Temperate or montane grasslands are not included in this range. They are seldom seen over 1,800m –2,100 m (5,900 ft–6,900 ft) in elevation. The wildebeests are not found in the wetter portions of the southern savanna, and notably in the miombo woodlands, except for a tiny size of Cookson’s wildebeest in Luangwa Valley in Zambia.

Three African blue wildebeest populations migrate considerable distances, timed to concur with the yearly cycle of grass growth and rainfall on the plains with short-grasses, where they may find the nutrient-rich fodder required for calf growth and lactation. The timing of the movement in both directions might vary significantly yearly. They move to dry-season locations after the conclusion of the rainy season because of a scarcity of drinking water. The animals return to their wet-season area when the rainy season returns after a few months. Migratory wildebeest populations can expand to substantially bigger numbers than resident populations due to their travels and access to nutrient-rich food for reproduction. Many long-distance nomadic populations of the wildebeests existed a hundred years ago, but all 3 are now disturbed, cut off, and gone (Serengeti, Kafue, and Tarangire).

Conservation and Threats

The Great Migration of the Blue Wildebeest
The Great Migration of the Blue Wildebeest

The main human-associated factors that populations face include water supplies drying up, large-scale deforestation, poaching and expanding settlements. Domestic cattle diseases like sleeping sickness can be transmitted to wildebeests and cause harm. Installation of fences that block migratory routes of these animals between the dry and wet season areas have caused mass deaths when animals are blocked off from regions of better pasture and water supplies they seek during droughts. According to research on the variables impacting the population of wildebeests in the Maasai Mara habitat, the populations have declined by roughly 80% from around 119,000 animals in 1977 down to around 22,000 individuals 20 years later. The primary reason was assumed to be agricultural development, which resulted in the loss of rainfall-season ranges and traditional breeding and calving grounds. Similarly, the Tarangire migration of wildebeests has recently seen significant decreases.

The population of the blue wildebeest is thought to be approximately 1,550,000 individuals. The general population trend is constant, and the Serengeti National Park population has climbed to almost 1,300,000. The population density in Etosha and Hwange National Parks vary from 0.15/km2 to 35/km2 in Serengeti and Ngorongoro Crater, where wildebeests are most abundant. These animals have been introduced into several private game ranches, parks, and conservancies. The International Union for Conservation of Nature considers blue wildebeests to be of least concern for these reasons. The eastern white-bearded wildebeests (C. t. albojubatus) population, on the other hand, has plummeted to around 6,000 – 8,000 animals, which is raising some concern.

Human-Wildebeest Relationship

The blue wildebeests, being among the great herbivores of eastern and southern Africa, is one of the creatures that draw travellers to the region to see big game, and consequently, it is vital to the region’s economy. Blue wildebeests have traditionally been killed for their meat and skins, with the hides producing high-quality leather although the flesh is gritty, dry, and rough.

Blue wildebeest, however, can have negative impacts on humans. They compete for pasture and water with domestic livestock, as well as transmit lethal illnesses such as rinderpest to livestock and spread epidemics. Ticks, flies, tapeworms, paramphistome flukes and lungworms can all be spread by them.

An old carved slate slab has been uncovered, portraying an animal that looks quite similar to a blue wildebeest. It was discovered at Hierakonopolis (Nekhen), which was the political and religious centre of Upper Egypt during the period, and dates back to roughly 3000 BC. This might indicate that the animal was formerly found in North Africa and was linked to the ancient Egyptians.

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