Probably the most endangered of all rhinoceros species. Numbers have declined by 50% due to poaching over the 1980's and 1990's. Fewer than 400 Sumatran rhino survive in very small and highly fragmented populations in Southeast Asia with Indonesia and Malaysia being the only significant range states. A 1997 IUCN estimate puts the total population of sumatran rhino at 400. The population of the borneo Sumatran Rhino at 100. The Malaya/Sumatra Sumatran Rhino population is at 300. For all the asian rhino species the estimate was 2500 and for the world population of all species of rhino at 13,565. Sumatran rhinos' numbers are believed to have plummeted by 50 percent or more during the 1980's and 1990's, according to the Asian Rhino Specialist Group for IUCN--The World Conservation Union.
The fires started in 1997 in Indonesia are threatening Sumatran Rhinos. The main concentrations of the Indonesian population of Sumatran rhinos (some 100-200 animals) are still outside the fire areas, but there are small groups in some of the affected protected areas that are very threatened, according to the Species Information Officer at WWF International.