Black rhino, Hook-lipped rhinoceros, Hooked lip rhino
Rhinos are very ancient animals. In fact, these mammals do resemble some prehistoric species. They appeared millions of years ago, during the Miocene era. One of the most conspicuous characteristics of these animals is the two horns of their head. African rhinos are represented by 2 species - the White rhino and the Black rhino. These two animals differ from each other in a number of ways. Their names refer not to their color pattern, but to the shape of their lips. African rhinos can occasionally be unpredictable and extremely dangerous. Hence, they have been fiercely persecuted. As a result, during a short period from 1970 to 1992, they lost as much as 96% of their total population. This became the largest population decline among all species of rhino. Black rhinos are represented by 4 subspecies, 3 of which are currently classified as 'critically endangered on the IUCN Red List.
An adult Black rhinoceros stands 140-180 cm (55-71 in) high at the shoulder and is 3-3.75 m (9.8-12.3 ft) in length. The females are smaller than the males. Their two horns on the skull are made of keratin with the larger front horn typically 50 cm (20 in) long, exceptionally up to 140 cm (55 in). The Black rhino has a pointed and prehensile upper lip, which it uses to grasp leaves and twigs when feeding, whereas the white rhinoceros has square lips used for eating grass. The Black rhinoceros can also be distinguished from the White rhinoceros by its size, smaller skull, and ears; and by the position of the head, which is held higher than the white rhinoceros, since the black rhinoceros is a browser and not a grazer. The thick-layered skin helps to protect Black rhinos from thorns and sharp grasses. It is commonly assumed that Black rhinos have poor eyesight, relying more on hearing and smell. However, studies have shown that their eyesight is comparatively good, at about the level of a rabbit. Their ears have a relatively wide rotational range to detect sounds. An excellent sense of smell alerts rhinos to the presence of predators.
The former range of this species used to cover a considerably large area across sub-Saharan Africa (except for the Congo Basin). The current range of Black rhinos geographically occupies South Africa, Namibia, Zimbabwe, and Kenya. These animals additionally occur in the territory between Cameroon and Kenya. Black rhinos are capable of living in different habitats such as deserts (particularly, those in Namibia), wooded grasslands, broadleaved woodlands, and acacia savannahs.
Black rhinos are generally solitary and sedentary creatures. They tend to live in the same area throughout their lives. They are not very territorial and often intersect other rhino territories. Males typically live alone before mating. Female rhinos, on the other hand, form small groups together with their young. The territories of these groups often overlap. In addition, females occasionally form temporary social units. Members of these groups travel and feed together. Black rhinos are most active in the morning and evening when they travel, feed, and drink. During the midday hours, they typically exhibit less activity. When feeling danger, they curl their tail and flee to escape the threat while emitting various snorting sounds. When the danger has passed, these curious animals start exploring the source of the threat. During the dry season of hot days, Black rhinos can often be seen taking mud baths, which help them to cool off. They get the required nutrients from salt licks of the area, to which they take occasional trips.
Black rhinos are herbivores (folivores, lignivores, frugivores, graminivores). They are browsing mammals, which generally consume leafy plants, branches, shoots, thorny wood bushes, grass and fruit.
Black rhinos are polygynous, which means that one male gets an exclusive right to mating with multiple females. Black rhinos breed year-round. However, they do have peak periods of breeding, which differ among populations, depending on geographical location. A single baby is born after 15 months of gestation. The mother keeps the calf hidden, until the latter is one week old, after which the baby comes out. During the following period, the mother and the calf communicate through special calls, which help them to find each other. The mother emits a panting sound, which is responded to by the squeal of the calf. By about one month old, the young rhino has learned to browse independently. At 4-5 months old, it begins to drink water. Black rhinos are weaned by 1.5 years old, although they become completely independent only after 4 years old. The age of reproductive maturity is 5-7 years old in females and 7-8 years old in males.
Hunting for sport and consumption has been one of the major threats to this species’ population. In addition, Black rhinos have been commonly hunted for their hides and horns. In the 1970s, for example, the horns of Black rhinos were highly demanded in Yemen. They served as a material for handles of traditional daggers, typically used by the wealthy to emphasize their social status. Unfortunately, these animals still attract hunters for their horns, which are illegally exported to Asian countries, where they are used in local traditional medicine. Presently, nearly all cases of Black rhino mortality are associated with poaching for their horns, which sharply decreases their numbers. These mammals are also facing the loss and destruction of their natural habitat due to the growing human population in the area, resulting in increased logging as well as the development of agriculture, roads, and human settlements.
According to the World Wild Life (WWF) resource, the total population of Black rhinos is more than 5,000 individuals. According to the IUCN Red List, the total population of Black rhinos is approximately 4,880 individuals. In December 2005, about 240 captive individuals of this species were estimated around the globe. These belonged to the subspecies of eastern black rhino and south-central black rhino. Currently, this species is classified by the IUCN Red List as Critically Endangered (CR) with its numbers increasing.
Due to their herbivorous diet, Black rhinos control plant communities of their range, thus benefiting the local ecosystem.