The Sumatran rhino is the most endangered large mammal on the Asian mainland — a species reduced to a few dozen individuals spread across five fragmented populations in Indonesia.
Weighing up to 800 kilograms, it is the smallest of the rhino species and the only Asian rhino with two horns.
Once found across Southeast Asia, it now clings to survival in Gunung Leuser National Park and in a handful of small, isolated populations in Indonesian Borneo. The species is biologically fragile in ways that go beyond poaching.
Sumatran rhinos have among the lowest reproduction rates of any mammal — females produce a single calf every 5-7 years.