This southern white rhino fetus, a 70-day-old male, was the result of in vitro fertilization. The mother, Curra, died before she could carry her calf to term.

Just two northern white rhinos are left on Earth. A new breakthrough offers hope

Photographs and video by Ami Vitale
Story by Kyle Almond, CNN
Published January 27, 2024

This southern white rhino fetus, a 70-day-old male, was the result of in vitro fertilization. The mother, Curra, died before she could carry her calf to term.

Jan Stejskal had just landed in Nairobi, Kenya, when he received the shocking news.

Curra, the rhinoceros he was arriving to check up on, was dead.

Heavy rains had flooded the animal’s enclosure at the Ol Pejeta Conservancy, setting free dormant bacteria spores that killed her and another rhino in November, it was discovered.

But amid the tragedy comes a beacon of hope — one that might save an entire subspecies from extinction.

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

During Curra’s postmortem, a 70-day-old male fetus was found in her womb. She had been pregnant.

A couple of months earlier, scientists with the BioRescue consortium implanted Curra, a 13-year-old southern white rhino, 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 Stejskal, the BioRescue 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.

Thomas Hildebrandt, the head scientist of the BioRescue group trying to save the northern white rhino from extinction, holds the southern white rhino fetus that was recovered from its dead mother. Now that the group knows a rhino pregnancy is possible via IVF, it will use northern white embryos next.

Arimet, a southern white rhino, is corralled at the Ol Pejeta Conservancy in Kenya. She could be implanted with northern white rhino embryos later this year.

To make the northern white rhino embryos, scientists used eggs from Fatu and combined them with sperm they had preserved from males before they died.

Scientists and conservationists are hoping that IVF can be used to save another rhino subspecies: the northern white rhino, which is critically endangered because of poachers who 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 and Fatu live at the Ol Pejeta Conservancy in Kenya, where they are protected from poachers and well taken care of. The 90,000-acre conservancy is in Kenya’s Laikipia District, between the foothills of Mount Kenya and the Aberdares.

Vitale was back in Kenya this month, visiting the Ol Pejeta Conservancy where Curra died. It 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.

“The northern white rhinos are just gentle, hulking creatures,” Vitale said. “They’re sweet. They grew up in a zoo. They’re not wild.”

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.

Zacharia Mutai, head keeper of the last two northern white rhinos, checks on Fatu and Najin at the Ol Pejeta Conservancy in Kenya. Behind them is Tauwo, a southern white rhino friend.

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.

“We wanted to prove that our approach works with southern white rhino genetic material, as it is more available,” he said. “By mastering this step, we can now use a northern white rhino embryo for the first time.”

The BioRescue team, together with officials from the Kenyan Wildlife Service, examine Arimet, a southern white rhino who is a candidate to be a surrogate mother for a northern white rhino.

Specimens from the last northern white rhinos are preserved in liquid nitrogen at the Ol Pejeta Conservancy in 2019. Scientists now have 30 northern white embryos, and they’re working on 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.

A rhino pregnancy lasts 16 months. So, if all goes well, we could see a northern white rhino baby in two to three years.

The 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.

Najin and Fatu grew up in a zoo in the Czech Republic, but for the past 15 years they have called Kenya home. The hope is that a northern white rhino baby is born soon and they can teach it their ways.

Vitale was in Kenya when the last male northern white rhino, Sudan, died in 2018. She had known him for years — “the most eligible bachelor in the world,” according to the dating app Tinder — but he was in poor health and had to be euthanized at the age of 45.

It was a heartbreaking time for Vitale and his keepers, who had grown to love his gentle soul and the affection he showed to everyone.

His death, however, was also a “galvanizing moment,” Vitale said, and scientists and conservationists continued to press on, looking for a way to save the subspecies.

“They just remind me that we just have to believe and start reimagining how we're going to do things differently — that all hope is not lost for the planet and all these extraordinary species that we share with it,” she said.

Sudan, the last male northern white rhino, is comforted before he died in 2018. He was 45 years old and in poor health.

Skejstal says he feels a “responsibility” to save the rhinos from extinction, and he is not alone. The effort to save the subspecies has cost millions of dollars, with many public and private donors contributing from all over the world.

“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.”

In 2009, four northern white rhinos were moved from a zoo in the Czech Republic to the conservancy in Kenya in a last-ditch effort to save the subspecies. The hope was that the climate and the extra room to roam would entice them to breed.

Dr. Julia Bohner of the BioRescue team stabilizes a southern white rhino named Jomo at the Ol Pejeta Conservancy in Kenya.

Jomo is secured by rangers with the Kenyan Wildlife Service so he can be sterilized to be a “teaser bull” and help the team know when the surrogate-to-be is in heat and ready to be implanted with embryos.

Both the Sumatran rhino and the Javan rhino are critically endangered, with each having under 100 rhinos left.

Among the scientists and those who work at the Kenyan conservancy, there is a great deal of excitement around the IVF pregnancy and the promise that it holds. It is bittersweet, however, as the milestone came with the death of Curra and her calf.

“We try to take control of every factor that affects the well-being of the animals, but in nature you cannot control everything and sometimes your plans are thwarted by heavy rains and a disease,” said Frank G?ritz, BioRescue’s head veterinarian. “It is very sad, but we try to look forward.”

Mutai rests with Najin at the Ol Pejeta Conservancy. Najin and Fatu are gentler than the southern white rhinos, photographer Ami Vitale said, because they were raised in a zoo and were used to being around people.

Vitale has witnessed the team overcome so many obstacles over the years, and because of its perseverance she is convinced that it will ultimately complete its mission.

“I’ve always believed that we will see northern white rhino babies, and it is just because I have so much faith in this team,” she said. “It's such a privilege to witness what they're doing so closely. I really believe that they will not accept failure. …

“We will see, in our lifetime, northern white rhinos roaming the plains of Kenya. I really believe that.”