Ratu Is Carrying a Fourth Calf. The Father of the Other Calf Is an Uncle.
Two Sumatran rhinos at Way Kambas are pregnant, due around May 2027. Ratu's calf would be her fourth. Delilah's sire is her paternal uncle. Eleven captive animals, all males related.
Two Sumatran rhino pregnancies, and a pedigree with nowhere to go
Ratu was taken from the forest in Sumatra in 2005. She is pregnant again, her fourth calf, fathered by Andalas. If the calf is born alive she would be the first Sumatran rhino known to have produced four. The old record, three, belongs to a female who lived at Cincinnati Zoo.
Her daughter Delilah is pregnant too. Delilah was born at the Sumatran Rhino Sanctuary in Way Kambas in 2016, to Ratu and Andalas. The father of Delilah's calf is Harapan. Andalas and Harapan are full brothers, born at Cincinnati in 2001 and 2007. Harapan is Delilah's paternal uncle.
Indonesia's Ministry of Forestry and Yayasan Badak Indonesia announced both pregnancies on 3 October 2026. Mongabay's Basten Gokkon reported them on 14 October. Both calves are due around May 2027. Gestation runs 15 to 16 months, and both pregnancies have already reached about eight months, which matters because early losses are common in this species. Calves stay with their mothers for up to two years.
The sanctuary holds 11 animals. They are the only Sumatran rhinos in human care. Every male traces back to Ipuh and Emi, the pair that lived in Cincinnati. Nina Fascione, executive director of the International Rhino Foundation, told Mongabay the keepers try to pair the least-related animals, and also have to consider body size. The options are the options. She said the immediate need to keep producing calves outweighs the genetic worry.
A few dozen Sumatran rhinos remain in the wild, split into fragments where a solitary male and a solitary female may never meet. Captive birth does not restock a forest by itself. It keeps a species from hitting zero while the forest question stays open.
Key Facts
- Announcement: 3 October 2026. Mongabay: 14 October 2026
- Ratu: fourth calf, sire Andalas. Delilah: second calf, sire Harapan, her paternal uncle
- Due around May 2027. About eight months pregnant. Gestation 15 to 16 months
- 11 captive animals, all males related, the only ones in human care
- A few dozen left in the wild
- Sources: Mongabay, Indonesian Ministry of Forestry, International Rhino Foundation
Why This Matters
A fourth calf is a record only if it is born. An uncle in the pedigree is the constraint the celebration has to carry in the same paragraph. The species is being kept alive by a family that is running out of outsiders.
What We Don't Know Yet
Neither calf has been born. Eight months is not sixteen. We do not have a 2026 wild census in this piece, only the standing estimate of a few dozen. A captive birth does not tell you whether Way Kambas, or any other forest, can hold a calf that is not behind a fence.