The Javan rhinoceros (more precisely Sunda rhinoceros) or lesser one-horned rhinoceros (Rhinoceros sondaicus) is a member of the family Rhinocerotidae and one of five extant rhinoceroses. It belongs to the same genus as the Indian rhinoceros, and has similar mosaicked skin which resembles armor. Once the most widespread of Asian rhinoceroses, the Javan rhinoceros ranged from the islands of Java and Sumatra, throughout Southeast Asia, and into India and China. The species is critically endangered, with only one known population in the wild, and no individuals in captivity. It is possibly the rarest large mammal on earth, with a population of as few as 40 in Ujung Kulon National Park at the western tip of Java in Indonesia.

The Javan Rhino is one of five living rhinoceros types, and is part of the same genus as the Indian Rhinoceros, but they are smaller. These Javan Rhinos were once abundant in Indonesia and Southeast Asia, but they are now on the Critically Endangered list with only about sixty (broken into two known populations) in the wild. There are no Javan Rhinos in captivity. The Vietnam War is cited to be one of the biggest deterrents to the Javan Rhino’s existence, in that it severely depleted its natural habitat. Some sources say that this rhino is THE rarest large mammal in the world, unlike the Fur-Nosed wombat, who is somewhere on the “Most Rare” list.