White-Tailed Gnu
The Black Wildebeest or White-tailed Gnu is one of two kinds of wildebeests that can be found in South Africa. The other species of wildebeest is known as the Blue Wildebeest or Black-tailed Gnu. There are distinct differences between the two species that can be pointed out with reference to their tails (as suggested in the names of each individual species) as well as their manes, and also the shape of their horns.
The Black Wildebeest has a white tail, hence the name 'White-tailed Gnu', and also has a white coloured mane. Whereas the Blue Wildebeest has a black tail, resulting the title of 'Black-tailed Gnu', as well as a black coloured mane.
Regarding the horns; the Black Wildebeest have horns that extend forward and bend to the front of the animal, in the frontal section of the face and not to the side.
The Blue Wildebeest have horns that extend from the sides of the skull and bend, and do not appear at the front. Size wise; the Black Wildebeest is generally smaller than the Blue Wildebeest.
The White-tailed Gnu (Connochaetes gnou) forms part of the family Bovidae, subfamily Alcelaphinae and is endemic to South Africa. The white-tailed gnu has a herbivorous diet and is predominantly a grazer, preferring the short grasses, but also feeding on other shrubs. Grass normally forms up to 90% of the diet. Water is an essential resource for these mammals, but they can survive without drinking every day. It has a distinctive white tail and an erect white mane, with males known to make loud 'ge-nu' calls.
Both the male and female black wildebeest have horns, but the males' horns are expanded at the base and are larger. Males also generally appear larger than females in size. These distinctive antelopes are mainly active during the day in the early hours of the morning and late afternoon hours. They seek to rest during the heat of the day.
There are three kinds of social organisations among the white-tailed gnu involving territorial males, bachelor groups or herds and female herds. The female herds, which consist of the females and their offspring, wander freely about. The territorial males mark their territories using scent marking. Bachelor herds are groups of wandering wildebeest made up of adult, subadult and yearling males.
Did you know? With research on these mammals it is always important to be able to determine the age of the animals in the population so that the age structure can be established, and this will indicate how stable a particular population of wildebeest is. The age is determined using three practical age classes, and these include:
Juveniles; animals born during the current year.
Subadults; animals born during the previous year, not yet sexually mature.
Adults; animals older than two years capable of breeding.
Larger animals are easier to age as it is better to distinguish between subadults and adults based on size. With the black wildebeest being quite a large mammal, one of the methods used to age this animal is that of body form and size. The larger animals are deemed to be the adults of the herd, with subadults growing to the same size but being noticeably smaller in size and having an immature form. Juveniles are easily distinguished by their small size and form.
Another method used hand in hand with that of form and size is the use of the horns to age the black wildebeest, as it can sometimes be easier than using size. This is done by noticing the differences in horn length, form and thickness as the animal ages. Juvenile wildebeest have very small horns that have not really taken shape yet, and have no upwards curve, only standing small and erect. The subadults' horns have the same form and curve as that of adults, but are not as thick at the base, and are smaller in size and length. Adults are distinguished by large horns that are fully formed, with an upwards curve and are thick at the base.
