Blue wildebeest is an easily recognized species of antelope with highly located shoulders and horns, resembling these of a cow. This animal resembles a broad and elongated muzzle. Blue wildebeests are known to gather in huge migratory herds. Blue wildebeests are so called due to the silvery-blue sheen of their fur, which actually varies from greyish to brown. The front feet of the animal exhibit black stripes, due to which this animal is nicknamed the 'brindled gnu'. The front part of its face, the mane as well as the long tail display black coloration. Their beards are long and colored in either black or white, depending on subspecies. This species exhibits sexual dimorphism with males, being noticeably bigger than females.
The natural range of this species occupies eastern and southern Africa. Blue wildebeests are found from Kenya to eastern Namibia and as far south as the Orange River in South Africa. Preferred types of habitat are acacia savannahs and plains with rapidly re-growing grasses and moderate levels of soil moisture. Nevertheless, Blue wildebeests may occur in different habitats such as dense bushes or open woodland floodplains.
Blue wildebeest are highly social creatures, gathering in one of the largest migratory herds among antelope species. This is basically caused by seasonal shortage of suitable food and water, as a result of harsh climate within their range. Meanwhile, populations in Serengeti-Masai Mara (Kenya/Tanzania) make up a part of the largest concentrations of large land mammals, found around the globe. Additionally, these animals constantly travel in search of suitable grass and water. Nevertheless, some individuals of this species prefer living in the same territory throughout the year, where they gather in small social units, consisting of a single alpha male as well as up to 10 adult females with their young. Females of these groups form dominance hierarchy, which is closed for outsiders. These animals spend the hottest part of the day resting. Periods of increased activity are the morning and late afternoon.
Blue wildebeest exhibit both polygynous (one male mates with multiple females) and polygynandrous (promiscuous) (both males and females breed with multiple mates) mating systems. The mating season lasts for 3 weeks, occurring just after the rainy season. Gestation period lasts for 8 months, yielding a single baby, which is capable of standing during the first 15 minutes after birth. The newborn calf will accompany its mother everywhere until 9 months old. By the end of this period, the young wildebeest is weaned, but continues living with its mother until the following breeding season, when a new calf is born. After that, young females remain in their natal herd, while males disperse. The age of reproductive maturity is 16 months old in females and 2 years old in males.
The biggest concerns to the population of this species are associated with human activities, due to which some populations cannot make their usual migration. For example, deforestation and irrigation practices bring to decline in water sources. On the other hand, fences don't allow these animals to travel. Some populations of Blue wildebeests regularly migrate to unprotected areas, where they suffer from loss of their natural habitat and are commonly poached. As a result, smaller populations of this species are restricted to protected areas. All of the above-mentioned factors are compounded by diseases, transmitted by cattle and negatively impacting the local Blue wildebeest populations.
According to the IUCN Red List, the total population of the Blue wildebeests is around 1,550,000 animals, including all five recognized subspecies: the Serengeti population - about 1,300,000 animals; 130,000 - Blue Wildebeest; 5,000-10,000 - Cookson’s wildebeest, and 50,000-75,000-Nyassa wildebeest. Eastern White-bearded Wildebeest are currently facing sharp population decline and are estimated to 6,000-8,000 individuals. Overall, population numbers of Blue wildebeests remain stable today, and the animals are classified as Least Concern (LC) on the IUCN Red List.
Due to grazing, these animals help to fertilize grasses, which they do through their urine and feces.