Rhinoceros sondaicus is a rare species of rhinoceros found in the Indonesian island of Java. This unique animal has several synonyms used to describe its physical characteristics and habitat. These synonyms include the Javan rhinoceros, lesser one-horned rhinoceros, and the Sunda rhinoceros. The animal's physical appearance is characterized by its single horn and distinctive skin folds that make it stand out from other rhinoceros species. These synonyms may be used interchangeably to refer to this critically endangered species, which faces various threats including habitat loss and poaching. Efforts to protect and conserve the remaining population of Rhinoceros sondaicus are ongoing, with collaboration from various conservation organizations and the Indonesian government.