Species Fact Profile: Sumatran Rhinoceros (Dicerorhinus sumatrensis)

Sumatran Rhinoceros

Dicerorhinus sumatrensis (Fischer, 1814)

Range: Once throughout Southeast Asia, now only in small pockets of Sumatra and Borneo
Habitat: Wetlands, Rainforests
Diet: Fruit, Bamboo, Leaves, Bark
Social Grouping: Solitary
Reproduction: Induced ovulators (unlike other rhino species), a single calf born after 15-16 month gestation period (usually born during the rainy season of October through May), calf becomes independent at 16-17 months of age and becomes sexually mature at 7-8 years old; births occur at 3-4 year intervals
Lifespan: 35-40 Years
Conservation Status: IUCN Critically Endangered, CITES Appendix I

• Smallest of the living rhinoceros species: head and body length 2.3-3.2 meters, shoulder height 1.1-1.45 meters, weight up to 1,000 kilograms
• Thick skin is covered with red-brown hairs; the coat is long and dense in younger animals, but becomes sparser in older individuals; it is believed to be related to the now-extinct woolly rhinoceros of Europe and Asia
• The only Asian rhinoceros which has two horns (though the second horn is often so short that it may not even appear to be present)
• Females maintain stable home ranges, males are slightly more nomadic, though both sexes may make seasonal movements to avoid flooding; both sexes mark home rnages with feces, urine, and soil scrapes
• Believed to be nocturnal, with the days spent lying in mud wallows or shallow pools.  Besides wallows and feeding grounds, a key component of every range is a salt-lick
• Very agile compared to other rhinos, with moderate climbing and swimming abilities
• Once there were three subspecies; D. s. lasiotis (mainland southeast Asia) is now probably extinct, D. s. harrissoni found on Borneo, D. s. sumatrensis found in Sumatra and Peninsular Malaysia
• Driven almost to extinction by habitat loss (mostly from palm oil plantations) and hunting for its horn, valued in traditional medicine.  Population numbers in the low 100s overall, but is highly fragmented
• Species has traditionally not thrived in captivity due to lack of knowledge of its biology and reproductive life; only successful captive births have occurred at the Calcutta Zoo and, over 100 years later, at the Cincinnati Zoo and Botanical Gardens, where three calves were produced.  The species is now also managed in protected sanctuaries in Sumatra.

Zookeeper's Journal: I have seen one - and only one - Sumatran rhinoceros in my life, and I fully expect that it is the only one I will ever see.  I traveled to Cincinnati in large part just to meet Harapan, the last Sumatran rhino outside of Indonesia... only to be told that he would soon be returning to Indonesia for breeding, following his older siblings.  The tale of the Sumatran rhino is an exasperating case of "If we'd known then what we know now."  It was the opinion of the staff that I'd talked with that (while I was in the holding building, scratching Harapan's hairy red butt), if we had enough rhinos in American zoos, with out new knowledge of their husbandry requirements and reproductive cycles, we could create a sustainable captive population, hopefully even reintroducing them back into the wild.  As it stands now, the species seems to be nosediving towards extinction, and I suspect that the rhino will be extinct within my lifetime.