A rare Sumatran rhino has given birth at an Indonesian sanctuary, encouraging researchers concerned for the species\' survival, officials said. A baby male rhino was born to Ratu, a 12-year-old Sumatran rhino living at the Sumatran Rhino Sanctuary in Indonesia\'s Way Kambas National Park, the International Rhino Foundation reported Monday. With fewer than 200 Sumatran rhinos living in Indonesia and Malaysia, it is one of the world\'s most endangered species. Their survival is threatened by loss of its tropical forest habitat and hunting pressure from poachers, who kill rhinos for their valuable horns, conservationists said. \"We are overjoyed that Ratu delivered a healthy calf and are cautiously optimistic that the calf will continue to thrive,\" Susie Ellis, the foundation\'s executive director, said. Two previous pregnancies for Ratu ended in miscarriages. \"We have been waiting for this moment since the sanctuary was built in 1998,\" Ellis said. The rhino calf weights between 60 and 70 pounds, she said. \"The little guy is absolutely adorable, and none of us has been able to stop smiling since the moment we were sure he was alive and healthy.\"