NAIROBI — Scientists have made history by successfully transferring a rhinoceros embryo for the first time, conservationists announced Wednesday, an achievement that could help save the embattled species from the growing threat of poachers.
The development is a milestone that scientists say opens the way to saving the endangered northern white rhino. Only two females exist in the world, Najin and daughter Fatu, and both are unable to carry pregnancies. Najin and Fatu live at Kenya’s Ol Pejeta Conservancy, which was also home to Sudan, the last male northern white rhino, which died in 2018.
Sudan’s death galvanized the world, motivating conservationists to try to save the species. Before that, in 2009 scientists had believed that there were only eight northern white rhinos alive on the planet, and they were all in zoos. When these rhinos did not breed, a team with a project called BioRescue went to Kenya in 2014 and decided to start working on another plan to save the species.
“This animal played a crucial role in a complex ecosystem before it got extinct for a while. It lived in the landscape and architecture of central Africa — bringing back the northern white rhino to this ecosystem will help to heal the ecosystem,” Thomas Hildebrandt, head of the project, told The Washington Post.
In 2019, scientists harvested oocytes — developing eggs — from Fatu and Najin, flying them to Avantea, a lab in Italy where they used the sperm of dead northern white rhinos for artificial insemination. The eggs were fertilized, with two resulting in viable embryos. A third embryo was created in 2020 using the same technique. There are now 30 embryos from the northern white rhinos that can be used to produce babies, and all are oocytes from Fatu, Hildebrandt said.
In the procedure announced Wednesday, scientists transferred a southern white rhino embryo to make sure the procedure could work. This way, no northern white rhino embryos were wasted. The successful transplanting of the embryo and the pregnancy of the southern white rhino surrogate involved the transfer of two southern white rhino embryos into a southern white rhino surrogate named Curra. Two embryos were used to increase the chance of a positive result.
Future surrogates of northern white rhinos will probably continue to be southern white rhinos until the subspecies can naturally breed again and are released in the wild, Hildebrandt said, which is likely to happen in the next 10 to 15 years.
The population of northern white rhinos started to shrink in central and parts of East Africa in the 1960s due to intense poaching for rhino horns. The northern white rhino and the southern white rhino are classified by the International Union for Conservation of Nature (IUCN) as subspecies of the white rhino.
With the latest development, scientists are now moving quickly. This year, there are plans to implant a surrogate with a northern white rhino embryo. Two surrogates named Arimet and Daly have been identified and will be likely recipients of the embryos.