The rhino is one of the oldest groups of mammals, virtually living fossils. 
Black rhinos are browsers. Their prehensile upper lip is adapted for grasping and holding leaves and branches of shrubs and trees.
Black rhinos have two horns. 
Populations of black rhino declined dramatically in the 20th century at the hands of European hunters and settlers. Between 1960 and 1995, black rhino numbers dropped by a sobering 98%, to less than 2,500. Since then, the species has made a tremendous comeback from the brink of extinction. Thanks to persistent conservation efforts across Africa, black rhino numbers have doubled from their historic low 20 years ago to between 5,042 and 5,455 today. However, the black rhino is still considered critically endangered, and a lot of work remains to bring the numbers up to even a fraction of what it once was—and to ensure that it stays there. Wildlife crime—in this case, poaching and black-market trafficking of rhino horn—continues to plague the species and threaten its recovery.
Habitat loss is the other major threat to rhino populations. As more and more land is cleared for agriculture there is less available space for rhino to thrive in. Rhino need a large area in which to feed and roam. If rhino populations end up fragmented, with no safe ‘corridors’ to travel through, chances of successful breeding and recovery will further decline.
Rhinos are also an important source of income from ecotourism.