The Biorescue consortium announced Thursday that it will no longer collect eggs from Najin, who is 32 years the oldest of the last two females in the world, and preserve her as a portal donor of cell tissue.
Fatu, Najin's daughter, therefore remains the only egg donor in this program which tries to revive the species on the brink of extinction.
"After weighing the risks and opportunities for individuals and for the species as a whole, we came to the conclusion that this was the only solution," Biorescue said in a statement.
Since 2019, the international Biorescue consortium has been collecting Najin and Fatu eggs for an unprecedented breeding program for rhinos.
In a very delicate procedure, the two females are anesthetized for a few hours and their eggs extracted using techniques that have required years of research.
The eggs are then sent to Italy to a laboratory specializing in fertilization, which uses the sperm of two dead male rhinos.
In July, Biorescue announced that it had proceeded to create three additional embryos, bringing their total to twelve.
All viable embryos come from the younger of the two females and this has prompted Biorescue to spare Najin who will remain a potential tissue donor if needed.
Fatu and Najin are unable to carry the embryos, which will have to be given to surrogate mothers of a related subspecies, the southern white rhino.
Sudan, the last northern white rhino, died in 2018 at Ol Pejeta Wildlife Park, Kenya, where Najin and Fatu live, under constant surveillance.
White rhinos do not have a natural predator, but have been decimated by poachers since the 1970s.
White rhinos have lived on Earth for 26 million years, and scientists estimate they were still over a million by the middle of the 19th century.
© 2021 AFPKeywords: najin, egg donor, fatu, nairobi, oldest, females, biorescue, eggs, rhino survival program, consortium, conclusion, afp, brink, france, techniques