Blue Wildebeest

Connochaetes taurinus

General Description

Scientific Name: Connochaetes taurinus

Subspecies:

Southern Blue Wildebeest (C. t. taurinus)
Western White Bearded Wildebeest (C. t. mearnsi)
Eastern White Bearded Wildebeest (C. t. albojubatus)
Nyassa Wildebeest (C. t. johnstoni)
Cookson's Wildebeest (C. t. cooksoni)

Other Names: Gnu, or just Wildebeest

Status: Least Concern (decreasing)

Population Estimate: 1,550,000

Population in Assessed Areas: 419

Diet: Herbivore - mixed browser & grazer

Male Size: 170-410 Kgs

Female Size: 140-260 Kgs

Trophy Size: 72.39 cm minimum

Generation Length: 7.5 years

Reproductive Season: March-May

Time of Activity: Diurnal/ semi-nocturnal

Description: Males are typically larger and weigh more than females. Males are usually around 170 - 410 kg and 130 - 150 cm tall (shoulder height), while females are about 140 - 260 kg and 122 - 135 cm tall (shoulder height).

Both males and females bear horns, which are smooth and well-developed, growing from a thick boss horizontally and slightly sideways and curving upwards towards the ends. However, female horns are lighter coloured, thinner, and associated with more minor bosses. Minimum trophy size can be reached by 3 years of age.

All the blue wildebeest subspecies are heavily built in the front and lightly built in the hind quarters, resembling a mix of cattle and antelope. They are often called “brindled” due to the dark, vertical stripes on the sides of their necks and shoulders and “blue” due to their dark blue or silver-grey pelage. They can also appear grey-brown. Calves are generally a light-brown colour. The blue wildebeest also has black hair forming a flat mane across the neck, a short beard under the throat, and a long tail. Blue wildebeest also have dark fur on their distinctive muzzle and face area. The white-bearded subspecies (C. t. mearnsi and C. t. johnstoni) have white beards instead of black and a light band across the muzzle.

Ecology: The preferred habitat for blue wildebeest consists of subtropical or semi-arid open bushland savannah plains and dry woodlands on the perimeter of bushveld, with predominant sweet grasses for food and surface water for daily drinking. Thickets, forests, slopes, plateaus, and regions of sourveld are, at best, marginal and, at worst, uninhabitable for blue wildebeest. Serengeti wildebeest populations, in particular, live in short grasslands during the rainy season and then migrate to taller grasslands where rainfall is higher in the dry season. When habitats and climate are optimal, blue wildebeest have limited impacts on veld, whereas they can be highly destructive in marginal habitats. An annual rainfall of around 250 - 450 mm is optimal, and snow can be lethal.

Blue wildebeest are highly-selective grazers of short sweetveld grasses (< 12 cm tall). 96% of their diet consists of sweetveld, and the remaining 4% consists of dicot forbs. When fodder becomes scarce, blue wildebeest migrate. Common dietary grasses include Panicum spp, Cynodon dactylon, Themeda triandra, Digitaria spp, S. obtusa, and Stipagrostis ciliata. Blue wildebeest drink around 9 - 12 liters of water every 1 - 2 days.

While blue wildebeest do not have fixed ranges due to being migratory animals, they are known to inhabit temporary home ranges of around 1,500 - 2,000 ha when food and water are plentiful. Additionally, when not migrating, dominant males establish temporary territories between 0.5 and 1.5 ha, which they defend against other males in the rutting season. These dominant territories become “floating islands” during migration, with the dominant bull defending a 30 to 50 m circle around him and his females.

Blue wildebeest form large family populations of between 10 to 150 individuals of both sexes and various ages. Smaller bachelor groups of between 6 to 20 immature bulls (around 2 - 2.4 years old) and non-dominant adult bulls also form, and these tend to operate in marginal habitats on the border of the large family herds. While neither cows nor bulls dominate family herds, sub-adult males are chased away during the rutting season and forced to join bachelor groups until they are mature enough to establish their own territories at around 4.5 years old. Family bonding between mothers and offspring is weak.

Blue wildebeest associate with zebra (Equus sp), baboon (Pappio sp), springbok (Antidorcas marsupialis), giraffe (Giraffa camelopardalis), waterbuck (Kobus ellipsiprymnus), and impala (Aepyceros melampus).

Behavior: Blue wildebeest can feed and roam day or night but tend to rest and ruminate under shade during the hot midday. Blue wildebeest tend to stay around 40 to 150 m away from any potential danger, and when forced to flee, they will run in single file up to 2 km away, only returning after a couple of days. Territorial bulls often run around their territory in a wide circle at the threat of danger.

Blue wildebeest are known for their annual migrations in response to seasonal food availability. During these migrations, wildebeest are hardly found further than 10 km away from drinking water as they depend on drinking at least every second day.

herd-of-blue-wildebeest-connochaetes-michael-poliza.jpg

Predation: Common predators (who particularly prey on wildebeest young) include the black-backed jackal (Canis mesomelas), side-striped jackal (Canis adustus), lion (Panthera leo), hyena (Hyaenidae sp), nile crocodile (Crocodylus niloticus), cheetah (Acinonyx jubatus), and wild dog (Lycaon pictus).

Reproduction: Mating occurs bimodally, with a peak between March and May and another peak in August. This means calves are born between November and January and in May.

Bulls reach sexual maturity at 36 months and social maturity at 4.5 - 5.5 years, while cows reach sexual maturity at 18 - 27 months and social maturity at 2.5 years. Cows aged 2 or older can mate with as many as three bulls each reproductive season. This occurs when family herds cross dominant bull territories. Cows have a gestation period of around 8.5 months and a calving interval of 10 - 18 months. Each cow gives birth to a single calf who runs with the family herd 5 - 10 minutes after birth. Mothers eat their calves' placentas to avoid attracting any predators. While calves wean at 8 months, they begin grazing as early as two weeks after birth. If a newborn calf dies soon after birth, the previous season’s calf will continue suckling until around 16 months old.

Conservation Analysis

Current & Historic range: Blue wildebeest currently inhabit Angola, Botswana, Eswatini, Mozambique, Namibia, South Africa, Tanzania, Zambia, and Zimbabwe. The specific ranges of each blue wildebeest subspecies are as follows (East, 1999):

Southern Blue Wildebeest: occupies a stretch across Namibia, Botswana, South Africa, Mozambique (north of the Orange River), Zambia (south of the Zambezi River), and southern/south-east Angola. Notable populations in Kafue and Liuwa Plain in Zambia, Etosha in Namibia, Okavango, Makgadikgadi-Nxai Pan, Ngamiland and the central/southern Kalahari in Botswana, Hwange in Zimbabwe, Kruger, Hluhluwe-Umfolozi and Mkuzi in South Africa, Hlane in Eswatini, and private farmland in Namibia, Botswana, Zimbabwe, and South Africa.
Western White-bearded Wildebeest: occupies northern Tanzania and southern Kenya. Notable population in the Ngorongoro Crater in Tanzania.
Eastern White-bearded Wildebeest: occupies northern Tanzania and central Kenya. Notable populations in Tarangire in Tanzania and Kajiado in Kenya.
Nyassa Wildebeest: occupies Mozambique (north of the Zambezi River) to eastern/central Tanzania. Notable population in Selous in Tanzania.
Cookson’s Wildebeest: only occupies Zambia (in the Luangwa Valley) but may have moved into central Malawi as vagrants

Map of Blue Wildebeest Distribution

Current & Historic Populations:

Total blue wildebeest population estimates made in the 1990s were around 1,200,000 individuals, with 70% of that being represented by the Serengeti-Mara population of around 942,000 individuals. In East (1999), the estimated population numbers outside of the Serengeti were:

150,000 C. t. taurinus, with around half on protected land and a quarter on private land
16,000 C. t. cooksoni, with around 60% on protected land
96,000 C. t. johnstoni, with around two-thirds on protected land (namely Selous)
94,000 C. t. albojubatus, with about two-thirds on or around protected land.

The most recent estimate for total blue wildebeest population size has increased to around 1,550,000 individuals (Estes & East, 2009), with about 1,300,000 C. t. taurinus making up the rebounding Serengeti population (Thirgood et al., 2004). Outside of the Serengeti population, Thirgood et al. (2004) estimates:

130,000 C. t. taurinus
5,000 to 10,000 C. t. cooksoni
50,000 to 75,000 C. t. johnstoni
6,000 to 8,000 C. t. albojubatus.

The current population trend is stable, and the IUCN ranks the blue wildebeest as being of Least Concern.

Historical blue wildebeest ranges stretched from southern Kenya to northeastern Namibia, crossing over Botswana, South Africa, and Mozambique (East 1999, 2013). Of note, C. t. johnstoni (Nyassa Wildebeest) historically occupied southern Malawi but has since become extinct there.

Historically, a Blue Wildebeest migration consisted of between 4 and 6 million wildebeest migrating a 2,000 km round-trip annually across the Serengeti. Furthermore, blue wildebeest once annually migrated between northern Botswana, Namibia, and South Africa, and across Kruger National Park to Mozambique’s Gorongosa marshes. The Botswana migration used to number over 1 million individuals before the creation of the Veterinary fence, which essentially killed the migration overnight. Unfortunately, current blue wildebeest migration has been restricted by fences denying access to water, causing such effects as the decline in Botswana wildebeest populations whose drought-induced migrations were blocked by cordon fences (Owens & Owens, 1980).

Threats to Species Survival: The primary threats to blue wildebeest are human development and competition with livestock, the degradation of available water by watershed deforestation, poaching, the blocking of migratory ranges, and infectious diseases (East, 1999; Estes, 2013). Exposing blue wildebeest to either black wildebeest or cattle increases the spread of contagious diseases such as malignant catarrhal fever and ocular-vascular myiasis (caused by Gidoelstia sp. larvae).

As blue wildebeest are migratory, they require seasonal access to unprotected ranges, meaning the management and protection afforded by national parks may be insufficient to prevent significant declines in population. Particular regions at risk of this are the Liuwa Plain, Tarangire, and Kajiado, while regions where wildebeest migration can occur entirely within protected areas include Kafue, Luangwa, Hwange, and Selous. Additionally, the loss of migratory abilities by fences or human development may result in the establishment of smaller, sedentary populations within fenced reserves and farms (East, 1999). A decrease in migratory wildebeest populations has occurred in Etosha National Park and Central Kgalagadi Game Reserve. The large Serengeti-Mara wildebeest population is also an essential conservation unit. While they have increased in numbers since the 1990s (Thirgood et al., 2004), the Ikoma Open Area and Mara Group Ranches found within the population’s migratory route are largely unprotected and, therefore, at risk of poaching and agricultural development.

Recommended Conservation Actions:

Further resource and manage protected areas where blue wildebeest populations exist.
Reintroduce blue wildebeest to areas they formerly occupied, such as Malawi, central Namibia, and large areas of South Africa.
Set harvest quotas and trade regulations for specific blue wildebeest populations.
Improve survey methods to get accurate population data, such as implementing long-term monitoring programs.

Economic & Cultral Analysis

Ecotourism Value: Very High

Hunting Value: High

Meat Value: High

Average Trophy Value: $1,200-1,800 USD

Meat Yield per Animal: 65-190 kg

Economic Value/Impacts: The value of Blue Wildebeest can range from incredibly valuable, to pest status depending on the location, and if livestock farming is common in that region. In national parks, private reserves and hunting properties, there is extreme value in having Blue Wildebeest on the landscape, as they are on of the most iconic African antelope species. For instance, the Serengeti Wildebeest migration attracts over 300,000 international tourists every year, bringing millions of dollars into the region & to local communities. In fact, their value may be so significant that in some areas, the demand for tourism opportunities are exceeding what the habitat can sustain, causing serious sustainability concerns.

They are also very valuable to the hunting industry, especially in South Africa, Namibia & Tanzania, where their ability to live in larger herds, without the need for consistent water means that they can thrive in the marginal land that most hunting operations operate on.

On the other hand, in areas where cattle farming is a predominant industry, Blue Wildebeest can be seen as a pest species. This partially because they directly compete for grass with cattle, but also because they are a host to a number of diseases such as Malignant Catarrhal Fever, Rinderpest, Blue Tongue, East Coast Fever, and many more. Whilst most of these diseases don't impact wildebeest much, they do have often fatal effects on cattle. The issue becomes even more important in countries like Namibia, Botswana & South Africa that have agreements with UE countries to export cattle from disease free zones to the northern hemisphere. Hence in these areas, blue wildebeest are often restricted to fenced areas, where the two species cannot overlap.

Cultural Value: Blue Wildebeest have likely been hunted by humans and our ancestors for millions of years, and due to their large size, historical abundance, and palatable taste, would have likely been a staple to many communities. It's known that hunter gatherer tribes from around the continent would have hunted wildebeest on a regular basis, especially where they conducted large scale annual migrations. In many areas, they may have been the most important prey animal of ancient peoples.

Wildebeests, also known as gnus, hold significant cultural symbolism in various African societies. They are revered for their resilience and ability to survive in harsh environments.