The Sumatran rhinoceros is the smallest living rhino and survives in Indonesia’s tropical forests.
It has two horns. Calves have dense hair that becomes sparser with age.
Sumatran rhinos produce calls lasting several seconds as well as short sounds. Captive animals have also been observed vocalizing while eating. One call combines a whistle with an immediately following burst of air. These usually solitary rhinos have several forms of vocal expression.
A 2003 acoustic study recorded one male and two female Sumatran rhinos at Cincinnati Zoo in March 2001 for a total of six hours. Twenty-minute recordings in the barn during morning, midday and early evening revealed three main call types: short eeps, longer whale-like sounds and whistle-blows. The short type was most common, while some longer calls lasted four to seven seconds. The male was not recorded producing the longer whale-like type during this study. Whistle-blows contained frequencies below the human hearing range. The researchers called for further work linking calls to behaviour.
An extinction-risk assessment has not been added yet.
On 25 November 2023, Delilah gave birth to her first calf, a male, at the Sumatran Rhino Sanctuary in Way Kambas National Park, Indonesia. She had herself been born there in 2016. A captive-born female producing the next generation marked a conservation-breeding achievement. The government-owned facility is managed by YABI, whose veterinarians and animal-care staff monitor the mother and calf. The programme aims eventually to supplement the declining wild population.