A Sumatran rhinoceros has given birth at an Indonesian sanctuary in a success for efforts to save the critically endangered species.

The International Rhino Foundation said the female calf was born on Thursday, weighs about 45 pounds (20 kilograms) and looks healthy and active.

Only an estimated 100 Sumatran rhinos remain, mostly on the island of Sumatra, and nine are in captivity.

The species was rediscovered in the Indonesian part of Borneo through their trails and footprints in 2013.

But one member of that small population on Borneo died in April after a wound from a poacher's trap became infected.

The calf is the second to its mother Ratu, who gave birth to a male named Andatu in 2012.