The smallest of the living rhinos and the only Asian rhino with two horns, Sumatran rhinos are covered with long hair. They are threatened by poaching and only two captive females have reproduced in the last 15 years.
Status: Critically endangered
Population: Fewer than 100
Found in: Sumatra and Borneo
What's being done: The World Wildlife Fund (WWF) is trying to stop poaching and protect its habitat. WWF is looking at moving the rhinos to intensively managed sites and focusing on captive breeding.
Black rhinos have a hooked upper lip, two horns and occasionally a third, small posterior horn.