The Javan Rhinoceros is one of the most critically endangered species alive today. In fact, there are estimated to be between only 24 and 44 individual animals that are still alive, all of which live in Indonesia. Being so rare, the Javan Rhinoceros has not been studied very closely for fear of interfering with its habits and habitat. Thus, much of what is known has been limited to observation, faecal analysis and rare physical investigations. This rhino subspecies is within the same genus as the Indian Rhinoceros and they, therefore, share many of the same characteristics.

One of the most noticeable features that these two subspecies share is their segmented skin, which resembles prehistoric armour plating. The plates are thick and tough, but the skin gets soft and flexible towards and in the folds, giving the rhino a distinct sense of comfort and flexibility of movement.

The Javan Rhino is slightly smaller than its Indian relative. although females are a little larger than males, the rhinos of this subspecies average a length (from their noses to the bases of their tails) of 3.2 metres (equivalent to about 10.5 feet). At shoulder height, this subspecies stands at approximately 1.5 metres (or 4.8 feet) tall. However, this can increase to about 1.7 metres (or 5.5 feet). An adult rhino will weigh between 900 and 2 300 kilograms, which is equal to between 2 000 and 5 000 pounds.

The Javan Rhino has only one keratin horn on its face, which has (as far as current knowledge extends) only been observed in males of the species. This horn will grow to be about 25 centimetres long, and continues to be the major cause of their near extinction, since they are poached for the medicinal and ornamental value of this horn.

It must be noted, however, that no medicinal applications have ever been scientifically proven to be existing within the keratin, and it is based purely on cultural beliefs and superstitions. This rhino uses its horn to pull plants down and to clear bushes in its path, rather than for fighting.

The Javan Rhinoceros has a long, hooked upper lip that enables it to hold onto long grasses, saplings, and so on. This lip gives its face an elongated look, much like it does the Black Rhino.

The Javan Rhino has three toes on its hoofed feet. Each toe has a strong nail. This enables the animal to scratch in the sand and traverse plains that are tough and unrelenting, without injuring its feet.