A living fossil.
The Black Rhino, or hook-lipped rhinoceros (Diceros bicornis) is a species of rhinoceros, found in eastern and central Africa. It is listed as critically endangered by the IUCN Red List of Threatened Species.
For the majority of the 20th century, the black rhino was the most numerous of all rhino species. In 1900, the population of the rhino was estimated at several hundred thousand. These numbers, however, dropped severely from about 70,000 in the late 1960s to only 10,000 to 15,000 in 1981. In the 1990s the number fell below 2,500, and in 2004 it was reported that only 2,410 black rhinos remained. (Emslie, 2012) The total rhino population had recovered to 4,240 by 2008, according to the International Rhino Foundation. A fully grown, adult black rhinoceros stands from 1.3 m to 1.8 m tall at the shoulder and measures 2.8 m to 3.8 m in length (plus a tail of about 60 cm). It usually weighs from 800 kg to 1,400 kg, however some anomalies have been reported at upwards of 2,200 kgs. As expected, the female black rhinos are smaller than their male counterparts. The rhino has two horns on his skull which are made of keratin, with the larger front horn typically 50 cm. In some cases it was found to measure up to 140cm. (Lewis, 2014) |
Horns are used primarily for defense, intimidation, and feeding. The black rhino has a pointed and prehensile upper lip (it is able to hold objects), which it uses to grasp leaves and twigs when feeding. The "hooked" lip of the black rhinoceros is an adaptation to help browsing efficiency.
The rhino possesses a thick layer of skin that helps to protect it from sharp vegetation (i.e. thorns). This skin is also a popular location for external parasites (ticks or mites, most commonly) which may be eaten by oxpeckers and egrets. These birds were at first believed to have a mutualistic relationship with the rhino, but now scientists believe that the oxpeckers may be feeding on rhino blood just like the insects. Black rhinos have poor eyesight, and must thus rely on their acute senses of hearing and smell. The ears of a rhinoceros have a relatively wide range of rotation to detect an equally large variety of sounds. Their sense of smell usually serves to alert the rhinos from predators. Overall, these animals have learned that humans are dangerous, and are thus frightened at the smell of humans. ("Diceros bicornis", 2006) |