An international team of scientists in Italy is racing against the clock to ensure that the only two northern white rhinoceroses left on the planet — both females, a mother, and daughter — are not the last of their kind. All they have to accomplish this task are a handful of oocytes (eggs) and a collection of frozen sperm.
Using sperm that had been collected from male rhinos before they died, the scientists were able to fertilize seven of the 10 oocytes. Dr. Cesare Galli, the managing director of Avantea, was working with scientists, veterinarians and conservationists from the Leibniz Institute for Zoo and Wildlife Research in Germany, the Dvur Kralove Zoo in the Czech Republic, and the Ol Pejeta Conservancy in Kenya to make this happen. The outcome was better than they had expected.
Jan Stejskal, the director of international projects at the Dvur Kralove Zoo, said:
We were really able to do something no one before has been able to do. We still don’t know whether we’ll have embryos, but it was successful anyway. We proved that there is a real chance for them to have offspring.
What made this endeavor most challenging was the fact that even artificial insemination using frozen sperm was unlikely to be an option for Najin and Fatu (the remaining two females) since neither seemed physically capable of carrying an embryo to term. Then, any last hope of natural mating vanished last year when the only male northern white rhino left died. His name was Sudan and he was the father of Naijin and grandfather of Fatu.
Stephen Ngulu, the veterinarian in charge at the conservancy, said:
When he died, it was a sad moment for all of us. We knew that we had some sperm that had been collected from him and several other males. So we knew that the only hope for the species was to get the eggs from the female.
That left the scientists with only one option: to put the females under general anesthesia and extract the eggs from the two rhinos using a probe guided by ultrasound. It was a risky procedure but their only chance.
Dr. Frank Göritz, the head veterinarian at the Leibniz Institute in Germany, was in charge of administering the anesthesia during the operation, which was also overseen by David Ndeereh of the Kenya Wildlife Service and Thomas Hildebrandt of the Leibniz Institute.
“It was a big day for us,” Dr. Göritz said. “It was quite successful.” Five eggs from each rhino were extracted during the procedure then sent to Italy to be fertilized by sperm that had been collected years earlier from two males named Suni and Saút. Both rhinos recovered perfectly from the anesthesia and operation.
It was unclear how many of the eggs fertilized would become blastocysts, the next step in embryonic development, admitted Dr. Galli. Even if it goes well, perfecting a technique for transplanting an embryo into a surrogate could take years, and gestation can last for 16 months or more. However, even if every egg were to fail, there should be opportunities to extract more. Dr. Galli said that the egg fertilization alone was a big step forward in terms of scientific achievement.
Dr. Göritz agreed saying:
It’s not only about saving the northern white rhino. We gained so much knowledge, and we used technology that we can now apply way earlier for other endangered species before they reach this situation.
