With fewer than 60 individuals remaining, the Javan rhino is the rarest of all the living rhinoceros species. It has a single horn and deeply folded skin that resembles armour plating. Like other rhinos, the species eats plants and spends most of its time wallowing in pools of mud to keep cool. Two subspecies exist, one in Vietnam and the other in Java. Both have been reduced to a single population as a result of extensive habitat loss and poaching for their horns. Although these populations are now protected in national parks, they remain at risk from poaching, and the small population sizes mean that they are extremely vulnerable to disease and natural disasters.