According to a paper published Wednesday in the journal Nature Communications, researchers have succeeded in creating embryos using frozen northern white rhino sperm and eggs from a southern white rhino, a closely related sub-species.
It’s the first time such hybrid embryos have been created and the scientists from Germany, Italy and the Czech Republic say it could provide a pathway to saving the critically endangered northern white rhino after the last male, called Sudan, died in March.
They plan to harvest the egg cells of the two surviving female rhinos soon and use preserved sperm to produce “pure” northern white rhino embryos. Since the females, a mother and daughter called Najin and Fatu, are unable to bear offspring themselves, the embryos would be implanted in a southern white rhino surrogate.
In order to increase the supply of eggs and preserve the northern white rhino’s genetic diversity, scientists are also working on a second method that would coax frozen skin cells from deceased animals into becoming egg cells, a procedure that has already succeeded in mice.
Thomas Hildebrandt, of the Leibniz Institute for Zoo and Wildlife Research in Berlin, said researchers hope the first northern white rhino calf will be born in about three years.
Saving the northern white rhino has become an international effort, with cooperation but also some rivalry among scientists and institutions around the world.
Some experts have criticized the effort however, saying it comes too late.
“I have no doubt that its purely scientific merit is laudable and it might have some application to endangered species conservation in the future,” said Richard Kock, a conservationist at Britain’s Royal Veterinary College who has worked extensively in Africa. “But I am afraid it is very much Nero fiddling after Rome is burning with respect to (northern) white rhino.”
Kock and fellow conservationists warned against focusing only on the northern white rhino sub-species, noting that its southern cousin has come back from the brink of extinction and now numbers some 21,000 individuals.
Instead, they suggested, work should focus on saving other endangered rhino species that can still be found in the wild.
Northern white rhinos were once abundant across Central and East Africa, but conflicts and poaching wiped them from their natural habitat.