Major scientific breakthrough gives hope in fight to save world's most endangered mammal

The last two northern white rhinos live under armed guard.

Mother and daughter, both former zoo animals called Najin and Fatu, are incapable of getting pregnant naturally. And after the death of the last male in 2018, it triggered an international scramble to prevent the species’ imminent extinction.

But now, at the Ol Pejeta Conservancy in Kenya, scientists have made a ­breakthrough, raising hopes of saving the most endangered mammal on the planet. Through the world’s first rhino IVF procedure, researchers transferred two laboratory-created southern white rhino embryos, a subspecies considered a close cousin of the northern white, into a surrogate called Curra in September.

But the Ol Pejeta project took a tragic turn when rain flooded the ­surrogate’s enclosure, releasing a dormant ­bacterium from the soil. Curra died from an ­infection 70 days into the pregnancy. A 6.4cm male foetus was retrieved which scientists say showed positive development.

Najin (background), and her offspring Fatu

“Witnessing the death of an animal you have worked with for so long for reasons beyond your control is depressing,” said Frank Gõritz, head vet of the BioRescue project. “It is sad, but we try to look forward and see it as a milestone.”

Satisfied the technique works, scientists want to repeat the process. Two new surrogates named Arimet and Daly have been selected, and a ‘teaser bull’ in the enclosure will signal when the female is at her peak for embryo implantation and gestation.

Scientists created the embryos using eggs harvested from Najin, 34, and Fatu, 22, and sperm preserved from two dead male northern white rhinos. The two last females will not be risked with pregnancy, but scientists hope they will have a role to play.

Thomas Hildebrandt, head of the BioRescue project, said: “We want the offspring to live together with Najin and Fatu to learn social behaviour of its kind. Although embryos can be stored in liquid nitrogen for a long time, we are in a rush to bring a northern white rhino baby to the ground so they can learn the language from the last two rhinos.”