Connochaetes gnou
black wildebeest
(Also: white-tailed gnu)

Originally, black wildebeest, or white-tailed gnus, ranged the highveld temperate grasslands during the dry winter and the arid karroo during the rains. However, due to hide-hunting in the 19th century, they were reduced to living on protected game farms in southern Africa. (Estes, 1991)

Connochaetes gnou lived in grasslands similar to the habitat of the common wildebeest, Connochaetes taurinus, when it ranged free. However, with its thicker, darker coat, black wildebeest are able to range farther south than the Orange River, past the edge of the acacia savannah, into colder climates. They rarely seek shade, and need little winter shelter. (Estes, 1991)

Black wildebeest are dark brown to black in color, males being darker in color than females. Both sexes become lighter in coat color in the summer, and develop shaggier coats in the winter. Like common wildebeest, C. gnou possesses a bushy beard and mane. However, C. gnou has a mane that stands up from its neck, rather than draping across the neck, like that of C. taurinus. This bristly mane is cream to white in color and black at the tips. The beard is black in color and stretches only along the lower jaw, not the length of the neck, as in C. taurinus. Additionally, black wildebeest have an area of longer, dark hair between the forelegs, covering the chest, and another patch of bristly black hair along the bridge of the nose. Male C. gnou stand 111 to 121 cm high and can be up to 2m in length, females are slightly smaller. Paired horns curve down, forward, and then up, like hooks, and are up to 78 cm in length (slightly thinner and shorter in females). The base of the horns is widened and flattened to form a protective shield. These differ from C. taurinus in that they project anteriorly, rather than laterally. Scent glands are present preorbitally, under the hair tuft, and on the forefeet.

Dental formula: 0/3, 0/1, 3/2, 3/3 (Talbot 1963) (Estes, 1991; Talbot and Talbot, 1963; Walker, 1968)

Dominant males defend access to a harem of females with which they mate. These territorial bulls are able to mate at any time, will call at twice the normal tempo, and may even froth at the mouth. There is suggestion that this calling helps to stimulate and synchronize female estrus, although there is also evidence that the lunar cycle triggers the mating peak. A rutting bull will never eat nor rest, as long as there are females within his territory. There are few courting rituals, besides males herding females with neck outstretched and chin in-line, urination on demand and flehmen (urine scenting). If a receptive female is uncooperative, a bull may rear in front of her with a full erection in a copulatory display. A receptive female will raise her tail when approached by a bull, swishing it across his face. Her tail remains up, sometimes, vertical, during mating, as the cow stands with her legs bowed, back arched. Females mate dozens of times with a male, often 2 or more times in a minute. (Estes, 1991)

Offspring gestate for 8 to 8.5 months, only 1 extremely precocial calf is born. Calving peaks in November-December (semi-dependent on timing and location of rains). Like C. taurinus, 80-90% of all calves are dropped within the three week birth peak. Calves can stand at 9 minutes post-parturition, and are grazing at least part time within one month. Calves are weaned after 4 months. Females mature at 1.5 to 2.5 years of age, males don't mature until 3 years of age.

Like most mammals, female black wildebeests nourish their young in utero, and then nurse them for several months after birth. Males provide no care for their young. Calves stay with their mothers until the next calf is born. Black wildebeest calves are capable of standing and running within hours of birth.

Black wildebeest can live for 20 years.

Like C. taurinus, wild C. gnou were migratory in large herds. Black wildebeest were never studied in their natural habitat, interacting with natural predators, however they seem to be more aggressive than their wild cousins, and have attacked and killed keepers while in captivity. The largest existing herd numbers 330 head at Willem Pretorius Game Reserve, Orange Free State. Herd size increases with forage density, female herds ranging from 14 to 32 and maintain a social dominance hierarchy. Unlike common wildebeest, black wildebeest do not groom each other or rub their foreheads on other wildebeest's croups because of the projection of their horns. However, they occasionally rub their cheeks on companions' necks.

Calves stay with their mothers until the next calf is born. These yearlings are driven out by the adult males. During this process, calves are often separated from their mothers, resulting in what may be the main cause of captive calf mortality. The yearlings form peaceful bachelor herds that may be tolerated by female groups late in the dry season. (Estes, 1991; Huffman, 2004; Walker, 1968)

Black wildebeest herds maintain a range of approximately 100 ha, dependending on the availability of space and quality of vegetation.

Male wildebeest determine dominance through classic head-ramming and front-pressing behaviors exhibited in most bovids, however the females maintain their rank primarily through head-nods and head-shakes. The white tail is lashed or waved in most C. gnou interactions, signalling anything from dominance to submission, and possibly serving as an auditory signal, as it can be heard up to half a kilometer away.

Black wildebeest eat the foliage of karroid bushes and shrubs. They live in somewhat arid regions and can subsist without drinking every day. (Estes, 1991)

Black wildebeest were once important herbivores in the ecosystems in which they live and served as an important prey base for large predators, especially in calving seasons.

Black wildebeest are part of the diverse wildlife that attracts tourists for safari.

Wild gnu are seen as competitors of commercial livestock. As well, many bovine diseases, such as rinderpest, travel from wildebeest to cattle. Wildebeest also carry parasites, including several kinds of ticks, flies, lungworms, tapeworms, and paramphistome flukes. (Talbot and Talbot, 1963)

Indiscriminate hunting and restriction of the best fertile land for farming has reduced the population sizes of many African antelope, including this species. Connochaetes gnou now exists only in contained populations on game farms and in zoos (Macdonald 1995). The IUCN rates it a species of Least Concern because of the large number of captive individuals. (Macdonald, 1995)