New Hope for the Last Two Northern White Rhinos on Earth

Last November, Curra-- a southern white rhinoceros at Kenya's Ol Pejeta Conservancy died.   Heavy rains had flooded the animal’s enclosure and it was discovered she had been infected by free dormant bacteria spores which eventually resulted in her death.  But amid the tragedy comes a beacon of hope — one that might save an entire subspecies from extinction.

 During the postmortem, a 70-day-old male fetus was found in Curra’s womb. She had been pregnant.  A couple of months earlier, scientists with the BioRescue consortium implanted Curra with two southern white rhino embryos, hoping that she would become a surrogate mother. Never before had a rhino been impregnated via in vitro fertilization.  “We knew that if it was from the embryo transfer, it would be a huge breakthrough,” said  JanStejskal, BioRescue's project coordinator.  Weeks later, DNA analysis confirmed that the pregnancy was the result of the embryo transfer. It was the world’s first IVF rhino pregnancy.

Scientists and conservationists are now hoping that IVF can be used to save another rhino subspecies: the northern white rhino, which is critically endangered because of poachers who have relentlessly hunted them for their horns. 

Only two northern white rhinos remain on the planet, and both of them are female. The last male, Sudan, died in 2018. Photographer Ami Vitale, who has been documenting the rhinos’ plight for 15 years now, is excited about what the future may now hold. “It's almost like a miracle,” she said.

Najin, left, and her daughter, Fatu, are the last two northern white rhinos remaining on Earth.

Ol Pejeta Conservancy is also the home of Najin and Fatu, the two remaining northern white rhinos. They are cared for around the clock and protected by armed workers.  Najin will be 35 years old this year. Her daughter, Fatu, will be 24. They are expected to live to about 40.  For various medical reasons, neither Najin nor Fatu is able to serve as a surrogate mother. But BioRescue, the group trying to save the northern white rhino, is planning to use southern white rhinos like Curra to act as surrogates. It believes there are enough similarities between the two subspecies to work.

For several years now, BioRescue has been creating northern white embryos with eggs from Fatu and sperm that was collected and preserved from males before they died.  There are now 30 northern white embryos, Stejskal said, and they’re continuing to produce more.  The next step is to select the new surrogates and implant them with the northern white embryos. Skejstal expects it to happen within the next six months.

Sudan, the last male northern white rhino, is comforted before he died in 2018.

 A rhino pregnancy lasts 16 months. So, if all goes well, we could see a northern white rhino baby in two to three years.T he embryos can be stored for a long time in liquid nitrogen, but scientists don’t want to waste time because the two existing northern white rhinos are not getting any younger.  “We want the offspring to live together with Najin and Fatu for years to learn the social behavior of its kind,” said Thomas Hildebrandt, BioRescue’s head scientist and an expert in wildlife reproduction based at the Leibniz-Institute of Zoo and Wildlife Research in Berlin.

Skejstal says he feels a “responsibility” to save the rhinos from extinction.  “The level of commitment of every party that is involved in the project is unusual, and I have never seen anything similar in any other project that I've worked in,” he said.  The northern white rhinos may not be the only rhinos to benefit from this IVF advancement.  “They will be able to use this technology and this groundbreaking science for other species,” Vitale said. “Immediately, we know it has the possibility of helping the Sumatran and Javan rhinos right away.”  Both the Sumatran rhino and the Javan rhino are critically endangered, with each having under 100 rhinos left.