Global populations of rhinoceros (white [Ceratotherium simum], black [Diceros bicornis], greater one-horned [Rhinoceros unicornis], Javan (Rhinoceros sondaicus], and Sumatran rhinoceroses [Dicerorhinus sumatrensis]) have declined alarmingly, from about 500,000 at the beginning of the 20th century to 29,000 in 2016, largely because of an escalation in poaching for rhinoceros horn (Biggs et al. 2013; TRAFFIC 2016). The current global rhinoceros population is composed of 3 Asian species and 2 African species. In Africa, they occur in South Africa, Kenya, Tanzania, Namibia, and Zimbabwe. In Africa, the southern white rhinoceros population is estimated at 20,700, and there are approximately 4885 black rhinoceroses. The greater one-horned rhinoceros occurs in Nepal and India and has a population of approximately 3555. The other Asian species are confined to Indonesia, and the populations are much smaller: <100 Sumatran and 58–61 Javan rhinoceroses (Save the Rhino International 2016a).