In the forests of Kutai Kartanegara, a lone female rhino named Pari carries something invaluable: the last viable genetic thread of her kind. With only two Bornean rhinos known to exist on Earth, Indonesian conservationists are preparing to attempt what has never been done before—capturing Pari and using her eggs to preserve her subspecies through in vitro fertilization.
Bornean rhinos, a subspecies of the Sumatran rhino, once roamed freely across their island namesake. Today, just two females remain: Pari, still living wild in the regency of Kutai Kartanegara, and Pahu, who resides at the Kelian rhino sanctuary. Conservationists have already attempted to extract eggs from Pahu, but at approximately 40 years old with various health complications, the process proved unsuccessful. Pari, appearing younger in camera trap images, represents the final hope.
"We carried out several simulations using cattle that are roughly the same size as Pari," said Ari Wibawanto, head of the provincial conservation agency in East Kalimantan. His team has spent months preparing for the capture, installing pit traps and refining their approach based on past tragedies. In 2016, a female Sumatran rhino died after relocation from injuries sustained in a poaching trap. Just last year, a Javan rhino died shortly after a world-first translocation for that species.
"We strengthened our procedures to make sure they don't cause technical problems, health issues or behavioral issues, so the animal doesn't get stressed," Wibawanto explained.
The science behind the effort draws encouragement from a landmark 2024 breakthrough: scientists in Germany successfully conducted IVF on a southern white rhino, proving the technique could work for another species. Because Sumatran rhinos are larger than their Bornean cousins, natural mating isn't feasible, making artificial fertilization the only viable path.
The plan is straightforward in concept but revolutionary in execution. Once Pari is secured, she'll be airlifted to a facility for monitoring before egg extraction. Her eggs will be fertilized with Sumatran rhino sperm in a laboratory, and if successful, a surrogate mother—likely a related subspecies—will carry the pregnancy to term. The team is also exploring cloning technology by collecting samples of Pari's skin and gum tissue.
The stakes extend beyond one subspecies. According to the International Rhino Foundation, fewer than 50 individuals each of the Javan and Sumatran rhino species remain in the wild, all in Indonesia. Saving the Bornean rhino means preserving genetic diversity that could strengthen rhino populations across the archipelago for generations to come.
For Wibawanto and his colleagues, the mission is urgent but not without hope. "Sumatran rhinos are larger than Bornean rhinos. So, if we try to mate them manually or through normal natural mating, it is likely that it will not work properly," he said. But science is offering a different path forward—one that might just ensure Pari's lineage outlasts the pressures that pushed her kind to the edge.