First-ever successful IVF pregnancy in rhinos could save species from extinction

A scientific breakthrough could be the key to saving one of the world’s most rare species of rhino: the northern white rhino. 

Scientists from BioRescue, an international group of researchers whose aim is to save the northern white rhino from total extinction, have successfully transferred the world’s first southern white rhino embryo produced in vitro into a surrogate mother. 

Bittersweet results

FILE - Curra, a southern white rhino chosen for surrogacy.  (Jan Zwilling/BioRescue)

The initial embryo transfer was performed on Sept. 24, 2023. Curra, the surrogate mother, was monitored on a daily basis at the Ol Pejeta Conservancy in Kenya. 

Researchers at BioRescue were set to perform a pregnancy test on Curra on Nov. 28, 2023, however, due to an unfortunate infection, Curra died on Nov. 25, 2023, according to BioRescue. 

While investigating what caused Curra’s death, researchers were fortunately able to confirm that Curra was indeed pregnant with a male fetus as a result of the IVF transfer. 

Even though Curra could not carry the unborn calf to full term, scientists were able to examine the fetus and found that it had organs and was well on its way to becoming a fully developed calf. 

FILE - The last two northern white rhinos, Najin and Fatu and an inlaid image of the first-ever successful IVF rhino fetus implanted into a southern white rhino. (Jan Zwilling/BioRescue)

"It is bitter that this milestone is confirmed under such tragic circumstances with the death of the surrogate Curra and her unborn calf, but I am certain that this proof of concept is a turn of the tide for the survival of the northern white rhino and the health of Central-African ecosystems. It comes just in time to achieve a pregnancy for northern white rhinos: we want the offspring to live together with Najin and Fatu for years to learn the social behavior of its kind," Thomas Hildebrandt, BioRescue project head, said in a statement. 

Why does this matter? 

This is the world’s first successful IVF rhino pregnancy. 

While southern white rhinos are more prevalent in the wild (about 16,000) their counterparts, the northern white rhino, are listed as critically endangered and extinct in the wild mostly due to poaching, according to the Save The Rhino website. 

There are only two northern white rhinos left – Najin and Fatu – and both are female. 

FILE - Najin and Fatu, the last northern white rhinos on Earth at the Ol Pejeta Conservancy. (Jan Zwilling/BioRescue)

The last male northern white rhino died at the Ol Pejeta Conservancy in 2018. 

"The successful embryo transfer and pregnancy are a proof of concept and allow to now safely move to the transfer of northern white rhino embryos – a cornerstone in the mission to save the northern white rhino from extinction," BioRescue said in a news release. 

Frozen embryos ready to go 

There are currently 30 frozen northern white rhino embryos in Berlin, Germany, and Cremona, Italy, awaiting transfer into southern white rhino surrogate mothers. 

Teams at BioRescue performed 13 total embryo transfers in rhinoceroses so far. 

"The embryo transfer technique is well established for humans and for domesticated animals such as horses or cows. But for rhinos, it has been completely uncharted territory and anything from the approach over procedure protocols to required equipment had to be invented, developed, tried and tested to be safe for use. Together with the team and many professional partners, I developed the devices that can actually find and access the required location where to insert the tiny embryo into a 2-ton animal. It took many years to get it right and we are overwhelmed that we now have proof that this technique works perfectly," Hildebrandt said. 

It will take a few months before scientists can attempt an embryo transfer with a northern white rhino specimen. 

Najin and Fatu

FILE - Najin and Fatu at the Ol Pejeta Conservancy.  (Jan Zwilling/BioRescue)

Najin, 34, and Fatu, 23, (mother and daughter) are the last remaining northern white rhinos in the world. Both have been under 24-hour watch by armed security at the Ol Pejeta Conservancy. 

Neither rhino is capable of naturally reproducing offspring, according to the conservancy, which is why the IVF embryos will be implanted into southern white rhinos. 

This story was reported from Los Angeles.