A. By the 1960s fewer than 70,000 black rhinos were left in Africa, and over the next two decades poachers wipe out 96% of them.
B. They were slaughtered on a large scale, mainly by white hunters, in the 19th and 20th centuries.
C. Only five species of rhino survive, in Africa and Asia.
D. Yet poaching and illegal trading are rife in Zimbabwe and Congo.
E. But since 1995, thanks to vigorous conservation efforts, the number of black rhinos has gone up again, to around 3,700.