In March 2016, a Sumatran rhinoceros (of the Bornean rhinoceros subspecies) was spotted in Indonesian Borneo. Though a number of rhinos died once at the various destinations and no offspring were produced for nearly 20 years, the rhinos were all doomed in their soon-to-be-logged forest. There was little or no information about procedures that would assist in ex situ breeding.
The species is much better studied than the similarly reclusive Javan rhinoceros, in part because of a program that brought 40 Sumatran rhinos into captivity with the goal of preserving the species. It is the most vocal rhino species and also communicates through marking soil with its feet, twisting saplings into patterns, and leaving excrement. The Sumatran rhino is a mostly solitary animal except for courtship and offspring-rearing. In 2015, researchers announced that the Bornean rhinoceros had become extinct from the northern part of Borneo ( Sabah, Malaysia) however, a tiny population was discovered in East Kalimantan in early 2016. The species was completely extirpated from Malaysia in 2019, and one of the Sumatran populations may already be extinct. Their numbers are difficult to determine because they are solitary animals that are widely scattered across their range, but they are estimated to number fewer than 80. They are now critically endangered, with only five substantial populations in the wild: four in Sumatra and one in Borneo. In historical times, they lived in southwest China, particularly in Sichuan. Members of the species once inhabited rainforests, swamps, and cloud forests in India, Bhutan, Bangladesh, Myanmar, Laos, Thailand, Malaysia, Indonesia, and China. A coat of reddish-brown hair covers most of the Sumatran rhino's body. Like both African species, it has two horns the larger is the nasal horn, typically 15–25 cm (5.9–9.8 in), while the other horn is typically a stub. It is the smallest rhinoceros, although it is still a large mammal it stands 112–145 cm (3.67–4.76 ft) high at the shoulder, with a head-and-body length of 2.36–3.18 m (7.7–10.4 ft) and a tail of 35–70 cm (14–28 in). It is the only extant species of the genus Dicerorhinus. The Sumatran rhinoceros, also known as the hairy rhinoceros or Asian two-horned rhinoceros ( Dicerorhinus sumatrensis), is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros.