Connochaetes gnou

Connochaetes gnou

The black wildebeest or white-tailed gnu (Connochaetes gnou Zimmermann, 1780) is a mammal belonging to the Bovidae family.

Systematics –
Domain Eukaryota,
Kingdom Animalia,
Phylum Chordata,
Class Mammalia,
Order Artiodactyla,
Family Bovidae,
Subfamily Alcelaphinae,
Genus Connochaetes,
Species C. gnou.
The following terms are synonymous:
– Bos gnou (Zimmermann, 1777);
– Antilope capensis (Gatterer, 1780);
– Antilope gnou (Zimmermann, 1780);
– Antilope gnu (Gmelin, 1788);
– Catoblepas operculatus (Brookes, 1828);
– Bos connochaetes (Forster, 1844).

Geographic Distribution and Habitat –
The wildebeest (Connochaetes gnou) is a species endemic to southern Africa that originally occupied vast areas of South Africa, Eswatini, and Lesotho. During the 19th century, populations were nearly exterminated due to intensive hunting, but today the wildebeest has been successfully reintroduced to its native range and introduced into new areas such as Namibia and Kenya.
Its preferred habitat is the open plains, grasslands, and scrublands of the Karoo, between 1,350 and 2,150 m above sea level. Currently, most individuals live in reserves and game farms, often sharing habitat with antelopes such as the white-fronted buck and the springbok.

Description –
The wildebeest (Connochaetes gnou) is characterized by marked sexual dimorphism.
Males reach 111–121 cm at the withers and 140–157 kg, while females measure 106–116 cm and weigh 110–122 kg.
Their body length ranges from 170 to 220 cm.
A distinctive feature is their long, white tail (80–100 cm), similar to that of a horse, which differentiates them from the blue wildebeest.
Their coat is dark brown or black, lighter in summer and shaggy in winter; young are born with tawny fur.
Both sexes have a thick, dark mane and forward-curving horns, up to 78 cm long, with males being more robust.
They have facial scent glands and pedals that secrete substances used for communication.
It is a long-lived species, with a life expectancy of up to 20 years.

Biology –
The white-tailed wildebeest (Connochaetes gnou) is a predominantly herbivorous mammal that feeds on over 90% grasses, supplementing its diet with shrubs. Water is essential, but it does not require daily drinking. It is especially active in the morning and late afternoon, reaching speeds of up to 80 km/h, and is highly stamina-driven.
Male white-tailed wildebeests reach sexual maturity at around three years of age, although they can mature earlier in captivity. Females, however, enter estrus for the first time and reproduce between one and two years of age. The species has only one reproductive cycle per year.
During the mating season, which coincides with the end of the rains and lasts for several weeks between February and April, a dominant male defends his harem, preventing other males from mating with the females in the group. When a female enters estrus, the male devotes all his attention to her, mating with her repeatedly. During this stage, the male exhibits various typical behaviors: lowering his neck, keeping his ears folded, sniffing the female’s vulva, urinating conspicuously, and resting his chin on her rump. The female, for her part, signals availability by holding her tail raised (sometimes vertically) or by swinging it over the male’s muzzle. After mating, the two usually separate, but in some cases the female follows her partner for a few minutes, nuzzling his rump with her muzzle. During this period, males tend to neglect grazing, progressively deteriorating in their physical condition. It is also not uncommon to observe mounting behavior even between individuals of the same sex.
Gestation lasts approximately 8.5 months and results in the birth of a single calf. Females in labor remain within the herd, repeatedly standing and lying down, until they give birth in low-growing grassy areas, generally in a prone position. Immediately after birth, the mother stands up, causing the umbilical cord to break, then vigorously licks the newborn and consumes the placenta. Despite regional differences, approximately 80% of births occur within two to three weeks of the start of the rainy season, between mid-November and late December. Seasonal reproduction has also been observed in European zoos, but twin births have never been recorded.
The calf, at birth, weighs approximately 11 kg and is covered in a shaggy, tawny coat. It can stand and run within minutes, an essential skill for survival in the wild. By the fourth week, all four incisors have developed, and two horn buds appear on its head, reaching 200–250 mm by the fifth month and becoming fully developed around the eighth. It is nourished by its mother’s milk for six to eight months, but begins to graze after just four weeks. It remains with its mother until the next calf is born the following year.
The social structure is complex and includes:
• herds of females with young,
• bachelor herds,
• territorial males.
Adult males defend territories of 100–400 m, marking them with excrement and display behavior. Interactions between males involve challenging rituals that can culminate in fights. The mating season occurs between February and April; after a gestation period of approximately 8.5 months, a single calf is born, which is already able to run shortly after birth.
The white-tailed wildebeest is susceptible to various diseases and parasites: it can be an asymptomatic carrier of the bluetongue virus, harbor internal and external parasites, and be vulnerable to anthrax and other tick-borne diseases.
The fossil ancestors of today’s white-tailed wildebeest already possessed the characteristics necessary for territorial defense, such as horns and a broad-based skull. The oldest known fossil remains were found in sedimentary rocks at Cornelia, in the Free State, and date back approximately 800,000 years. Other fossils have been discovered in the Vaal River deposits, but it is unclear whether they are as old as those found at Cornelia. Horns belonging to white-tailed wildebeest have been found in sand dunes near Hermanus, South Africa, a location far from the species’ current range; scientists have speculated that these animals may have migrated to that region from the Karoo.
This species can interbreed with the blue wildebeest, its close relative. There have been several reports of male white-tailed wildebeest mating with female blue wildebeest, and vice versa. Differences in social behavior and habitat preferences have historically prevented interspecific hybridization between the two animals, but it can occur when both are confined to the same area. The resulting offspring are generally fertile. A study of these hybrids at the Spioenkop Dam Nature Reserve in South Africa revealed that many had disadvantageous anomalies involving teeth, horns, and wormian skull bones. Another study reported that the hybrids were larger than those of both parents. In some specimens, the auditory bullae were significantly deformed, and in others, the radius and ulna were fused.

Ecological Role –
The wildebeest (Connochaetes gnou) belongs to the Bovidae family and the genus Connochaetes, of which it is one of two species, along with the blue wildebeest (Connochaetes taurinus). The genus name derives from the Greek kónnos (“beard”) and khaítē (“mane”), while the specific epithet gnou derives from the term khoikhoi. This species’ evolutionary lineage diverged from that of the blue wildebeest about a million years ago, in the Middle-Upper Pleistocene. As mentioned, hybridization with the blue wildebeest is also known, producing fertile offspring but often with morphological abnormalities.
Once the primary herbivore of the southern African plains, it was a key food source for large predators such as lions, hyenas, and wild dogs. Even today, although fewer in number than in the past, they still play an important role in ecosystems as a regulator of herbaceous vegetation and a prey for carnivores. They are also a host for numerous parasites, contributing to the ecological dynamics of insect and pathogen populations.
Before the arrival of Europeans in the area, wildebeest moved across a vast area, likely linked to the arrival of rains and the availability of forage. They never undertook migrations as large as those of the blue wildebeest, but in the past they crossed the Drakensberg range, moving east in autumn in search of good pastures. They then returned to the Highveld in spring, heading west, where sweet potatoes and Karoo vegetation were abundant. They also moved from north to south when the Digitaria insularis grass north of the Vaal River ripened, taking on an unpleasant flavor, as they ate only the young shoots. Today, almost all wildebeest live in reserves or on farms, and the extent of their movements is limited.
This bovid has had and continues to have economic value for humans: its hide is used for leather, its meat is used to make traditional South African biltong, and its long tail is used to make fly swatters. It also represents a tourist attraction in nature reserves. However, it can compete with domestic livestock and act as a reservoir for livestock diseases.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Gordon Corbet, Denys Ovenden, 2012. Guide to the Mammals of Europe. Franco Muzzio Editore.
– John Woodward, Kim Dennis-Bryan, 2018. The Great Encyclopedia of Animals. Gribaudo Editore.