Two Sumatran rhinos are pregnant in Indonesia — Mongabay
Two females of this critically endangered species, Ratu and her daughter Delilah, are pregnant at the Sumatran Rhino Sanctuary in Way Kambas, Indonesia. Indonesia’s Ministry of Forestry and the non-governmental organization Yayasan Badak Indonesia, which manages the sanctuary, announced this on October 3. Both calves are expected around May 2027, Mongabay reports.
Two upcoming additions
Ratu, who was captured in the wild on Sumatra in 2005, is carrying her fourth calf by the male Andalas. If the calf is born healthy, Ratu will become the first known Sumatran rhino to give birth to four calves. Until now, the record was three calves, held by a female at the Cincinnati Zoo in the United States.
Delilah was born at the Way Kambas sanctuary in 2016 to Ratu and Andalas. She is carrying her second calf by Harapan. Andalas and Harapan are full brothers, born at the Cincinnati Zoo in 2001 and 2007, respectively. Therefore, Harapan is the paternal uncle of Delilah’s future calf.
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Limited genetic diversity
Indonesia’s breeding program keeps 11 Sumatran rhinos — all of the species’ individuals in captivity worldwide. All males in the program are related. Sanctuary specialists try to pair the least closely related animals, but their options are limited by the small number of rhinos under human care. Veterinarians will continue intensive monitoring of Ratu and Delilah until they give birth.
According to an assessment by the IUCN Asian Rhino Specialist Group, between 34 and 47 Sumatran rhinos remain in the wild in Indonesia. They live in several isolated groups, with the largest viable population believed to be in the Leuser Ecosystem in northern Sumatra. Due to habitat fragmentation, solitary males and females are finding it increasingly difficult to meet for breeding.
Ratu’s and Delilah’s pregnancies have already lasted about eight months. Pregnancy in Sumatran rhinos generally lasts around 15–16 months, and calves may depend on their mothers for up to two years. Since the breeding program began in 1984, five calves have been born at the sanctuary, with the latest in 2023.
