Siti said the mother and calf were both doing well after the birth.
"This news is certainly happy news, not only for the Indonesian people but also the world. I give my highest appreciation to the parties involved in the birth of this Sumatran rhino. Hopefully, we can continue to receive happy news from the births of Sumatran rhinos and other protected animals in the future," Siti said in a news release.
The birth marks the fourth calf born as part of the Indonesian conservation breeding program and brings the sanctuary's total number of rhinos to nine.