The Black Rhinocres, or Hook-lipped Rhinocres is a species of rhinoceros, native to the eastern and central areas of Africa including Kenya, Tanzania, Cameroon, South Africa, Namibia, Zimbabwe, and Angola. Although the rhino is referred to as black, it is actually more of a grey/brown/white color in appearance.
The other African rhinoceros is the white rhinoceros. These common names are misleading, as these two species are not really distinguishable by color. The word "white" in the name "white rhinoceros" is a misinterpretation of the Afrikaans word wyd, itself derived from the Dutch word wijd for wide, referring to its square upper lip, as opposed to the pointed or hooked lip of the black rhinoceros. These species are now sometimes referred to as the square-lipped (for white) or hook-lipped (for black) rhinoceros.
The species overall is classified as critically endangered, and one subspecies, the Western Black Rhinoceros, was declared extinct by the IUCN in 2011.
An adult black rhinoceros stands 132–180 cm (52–71 in) high at the shoulder and is 2.8–3.8 m (9.2–12 ft) in length, plus a tail of about 60 cm (24 in) in length. An adult typically weighs from 800 to 1,400 kg (1,800 to 3,100 lb), however unusually large male specimens have been reported at up to 2,199–2,896 kg (4,850–6,380 lb). The females are smaller than the males. 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 longest known black rhinoceros horn measured nearly 1.5 m (4.9 ft) in length.Sometimes, a third, smaller horn may develop. These horns are used for defense, intimidation, and digging up roots and breaking branches during feeding. The black rhino is smaller than the white rhino and has a pointed and prehensile upper lip, which it uses to grasp leaves and twigs when feeding. 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. This key differentiation is further illustrated by the shape of the two species mouths (lips): the "square" lip of the white rhinoceros is an adaptation for grazing, and the "hooked" lip of the black rhinoceros is an adaptation to help browsing.
Their thick-layered skin protects the rhino from thorns and sharp grasses. Their skin harbors external parasites, such as mites and ticks, which are eaten by oxpeckers and egrets that live with the rhino. Such behavior was originally thought to be an example of mutualism, but recent evidence suggests that oxpeckers may be parasites instead, feeding on rhino blood. Black rhinos have poor eyesight, relying more on hearing and smell. Their ears possess a relatively wide rotational range to detect sounds. An excellent sense of smell alerts rhinos to the presence of predators.
Although they are typically solitary animals, with the exception of coming together to mate, mothers and calves will sometimes congregate in small groups for short periods of time. Males are not as sociable as females, although they will sometimes allow the presence of other rhinos. They are not very territorial and often intersect other rhino territories. Home ranges vary depending on season and the availability of food and water. Generally they have smaller home ranges and larger density in habitats that have plenty of food and water available, and vice versa if resources are not readily available. In the Serengeti home ranges are around 43 to 133 km2 (17 to 51 sq mi), while in the Ngorongoro it is between 2.6 to 44 km2 (1.0 to 17 sq mi). Black rhinos have also been observed to have a certain area they tend to visit and rest frequently called "houses" which are usually on a high ground level.
The black rhino has a reputation for being extremely aggressive, and charges readily at perceived threats. They have even been observed to charge tree trunks and termite mounds. Black rhinos will fight each other, and they have the highest rates of mortal combat recorded for any mammal: about 50% of males and 30% of females die from combat-related injuries. Adult rhinos normally have no natural predators, thanks to their imposing size as well as their thick skin and deadly horns. However, adult black rhinos have fallen prey to crocodiles in exceptional circumstances. Calves and, very seldomly, small sub-adults may be preyed upon by lions as well.
Black rhinoceros follow the same trails that elephants use to get from foraging areas to water holes. They also use smaller trails when they are browsing. They are very fast and can get up to speeds of 56 kilometers per hour (35 mph) running on their toes.
The black rhinoceros is a herbivorous browser that eats leafy plants, branches, shoots, thorny wood bushes, and fruit. Their diet can reduce the amount of woody plants, which may benefit grazers (who eat grass), but not competing browsers. It has been known to eat up to 220 species of plants. It can live up to 5 days without water during drought. Black rhinos live in primarily grasslands, savannas, and tropical bushland habitats. They browse for food in the morning and evening. In the hottest part of the day they are most inactive- resting, sleeping, and wallowing in mud. Wallowing helps cool down body temperature during the day and protects against parasites. If mud is not available rhinos will take dust baths. Drinking water is most common in the afternoon. When black rhinos browse they use their lips to strip the branches of their leaves.