The Indian rhinoceros (Rhinoceros unicornis), also known as the greater one-horned rhinoceros, great Indian rhinoceros or Indian rhino, is a rhinoceros species native to the Indian subcontinent. It is the second largest living rhinoceros and the largest in Asia, with adult males weighing 2.07–2.2 t (2.04–2.17 long tons; 2.28–2.43 short tons) and adult females 1.6 t (1.6 long tons; 1.8 short tons). Its thick skin is grey-brown with pinkish skin folds. It has a single horn on its snout that grows up to 57.2–61.6 cm (22.5–24.3 in) long. Its upper legs and shoulders are covered in wart-like bumps, and it is nearly hairless aside from the eyelashes, ear fringes and tail brush. The Indian rhinoceros occurs in the Indo-Gangetic Plain in 12 protected areas in northern India and southern Nepal. It is a grazer, eating mainly grass, but also twigs, leaves, branches, shrubs, flowers, fruits and aquatic plants. It is a largely solitary animal, only associating in the breeding season and when rearing calves. Females give birth to a single calf after a gestation of 15.7 months. The birth interval is 34–51 months. Captive individuals can live up to 47 years. It is susceptible to diseases such as anthrax, and those caused by parasites such as leeches, ticks and nematodes. The Indian rhinoceros is listed as Vulnerable on the IUCN Red List, as the population is fragmented and restricted to less than 20,000 km2 (7,700 sq mi). Excessive hunting and agricultural development reduced its range drastically. In the early 1990s, the global population was estimated at between 1,870 and 1,895 individuals. Since then, the population increased due to conservation measures taken by the governments. As of March 2025, it was estimated to comprise 4,075 individuals. However, poaching remains a continuous threat.
Etymology The generic name rhinoceros is derived through Latin from the Ancient Greek: ῥινόκερως, which is composed of ῥινο- (rhino-, "of the nose") and κέρας (keras, "horn") with a horn on the nose. The name has been in use since the 14th century. The Latin word ūnicornis means "one-horned".
Taxonomy Rhinoceros unicornis was the scientific name used by Carl Linnaeus in 1758 who described a rhinoceros with one horn. As type locality, he indicated Africa and India. The Indian rhinoceros is a monotypic taxon. Several zoological specimens were described since the end of the 18th century under different scientific names, which are all considered synonyms of Rhinoceros unicornis today:
R. indicus by Cuvier, 1817 R. asiaticus by Blumenbach, 1830 R. stenocephalus by Gray, 1867 R. jamrachi by Sclater, 1876 R. bengalensis by Kourist, 1970
Evolution
Ancestral rhinoceroses first diverged from other perissodactyls in the Early Eocene. Mitochondrial DNA comparison suggests the ancestors of modern rhinos split from the ancestors of Equidae around 50 million years ago. The extant family, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the Miocene. The last common ancestor of living rhinoceroses belonging to the subfamily Rhinocerotinae is suggested to have lived around 16 million years ago, with the ancestors of the genus Rhinoceros diverging from the ancestors of other living rhinoceroses around 15 million years ago. The genus Rhinoceros has been found to be overall slightly more closely related to the Sumatran rhinoceros (as well as to the extinct woolly rhinoceros and the extinct Eurasian genus Stephanorhinus) than to living African rhinoceroses, though there appears to have been gene flow between the ancestors of living African rhinoceroses and the genus Rhinoceros, as well as between the ancestors of the genus Rhinoceros and the ancestors of the woolly rhinoceros and Stephanorhinus. A cladogram showing the relationships of recent and Late Pleistocene rhinoceros species (minus Stephanorhinus hemitoechus) based on whole nuclear genomes, after Liu et al., 2021:
The earliest fossils of the genus Rhinoceros date to the Late Miocene, around 9 to 8 million years ago. The divergence between the Indian and Javan rhinoceros is estimated to have occurred around 4.3 million years ago. The earliest representatives of the modern Indian rhinoceros appeared during the Early Pleistocene at 2.6 to 0.8 million years ago; fossils indicate that the Indian rhinoceros during the Pleistocene also inhabited areas considerably further east of its current distribution, including mainland Southeast Asia, South China and the island of Java, Indonesia. They also appear to have ranged as far south as Tamil Nadu in India, based on subfossil remains as recent as the Neolithic. A Late Pleistocene partial fossil skeleton of R. unicornis was described from Kanchanaburi province in Thailand in 2018. Several fossil Rhinoceros species from South Asia, such as R. palaeindicus and R. sivalensis from the Late Pliocene or early Pleistocene of Nahan, R. deccanensis from the Pleistocene of Karnataka and R. namadicus from the Pleistocene of Madhya Pradesh are potentially synonymous with R. unicornis.
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