Northern White Rhino Gets Pregnant From Embryo Transfer; Can IVF Save the Species From Extinction?

On March 19, 2018, the last male northern white rhino, Sudan died at 45. This signaled the imminent disappearance of the species. Only two infertile female northern white rhinos, Fatu and Najin, were left under 24-hour armed protection at a conservation reservation in Kenya. But thanks to new scientific advancements, the mother and daughter may not be the last of their kind.

(Photo: Wikimedia Commons/ Sirrob01)

Uncharted Territory

On January 24, scientists announced the first successful embryo transfers in southern white rhinos, a technique that can also be used for their rarer northern relatives. The experiment was carried out by a group of experts from BioRescue, a consortium supported by the German government that aims to prevent rhino extinction.

The sperm was collected at Zoo Salzburg in Austria from a southern white rhino named Athos. Meanwhile, the egg cells were taken from Elenore, a southern white rhino kept in the Pairi Daiza Zoo in Belgium. The samples were transferred to Italy and underwent in vitro fertilization (IVF).

In September 2023, the two embryos were implanted into a surrogate mother named Curra from Ol Pejeta Conservancy in Kenya. The implantation process included Ouwan, a male "teaser" bull, who stimulated typical mating behaviors.

The technique resulted in a successful pregnancy. Although this method is commonly used in humans, cows, and horses, it has never been used in rhinos. Experts describe the process as "uncharted territory" since the methods, protocols, and equipment were developed from scratch.

Unfortunately, the father and the pregnant mother were found in November 2023 when the fetus was just 70 days old. Scientists believe that the couple contracted a severe bacterial infection after extremely heavy and climate change-related rains flooded the surrogate enclosure.

However, scientists noted that the pregnancy proved that this strategy could work. According to Leibniz Institute for Zoo and Wildlife Research professor Thomas Hildebrandt, this method could be a key step in saving the northern white rhino.

Saving an Extinct Species

Experts plan to conduct a similar technique in northern white rhinos by May or June this year. There are currently 30 embryos left, stored in liquid nitrogen at -196 degrees Celsius in Cremona, Italy, and Berlin, Germany,

The embryos were created using eggs from Fatu and sperm collected from two now-dead males. A southern white rhino surrogate in Kenya will be injected with the embryo through its anus. If the 16-month pregnancy becomes successful, it would be the first northern white rhino born since 2000.

Scientists also plan to perform more embryo transfers if the first attempt succeeds. This means that as many as six northern white rhino calves can be born in a short period. It is also important that the calves meet Fatu and Najin while they are still alive to learn how to behave like a northern white rhino.

Hildebrant explained that the calves will not be genetically diverse enough to produce a viable population, even if several are born. This is because the 30 surviving northern white rhino embryos are all made from Fatu's eggs and sperm from two males.