These massive mammals have long been hunted for their horns, which are erroneously believed to have healing properties. The western black rhino is already extinct and there are only three northern white rhino left. There is still a small population of Javan Rhinos in Indonesia, but two other subspecies, one in Vietnam, have also gone extinct. In 2016, numbers showed that the previous year was the worst year ever for rhino poaching. Given the trends, scientists predict that the entire wild rhino population will go extinct between 2021 and 2031. Many of the horns already on the market are fake, and some companies are trying to deal with the crisis by flooding the rhino horn market with 3-D prints of rhino horns, under the dubious assumption that this will make poaching less lucrative. However, some conservationists argue that it could actually make things worse by removing the stigma about using the horn and making it harder for law enforcement officers to track poachers.