World first IVF rhino pregnancy could save northern white rhinos from extinction, scientists say

(CNN) — A world first in rhinoceros reproductive health could save northern white rhinos from extinction, scientists said Wednesday.

The team at the BioRescue project successfully impregnated a southern white rhino via in vitro fertilization (IVF), according to a press release, creating a possible path for restoring the northern white rhino species.

Northern white rhinos are critically endangered and the only two remaining rhinos, Najin and Fatu, are infertile females that live under constant surveillance in Kenya.

However, there are living cells from 12 different northern white rhinos stored in liquid nitrogen in Italy and Germany.

The impregnation of the southern white rhino was an international effort to save the species.

‘Uncharted territory’

The sperm was collected from a southern white rhinoceros named Athos, who lives at Zoo Salzburg in Austria. The egg cells were retrieved from Elenore, a southern white rhinoceros living in the Pairi Daiza Zoo in Belgium. The samples were then transferred to Italy and fertilized in vitro.

Two embryos were transferred to Kenya and implanted in a surrogate mother, named Curra, at the Ol Pejeta Conservancy in September 2023. The process of implanting the embryos included using a male “teaser” bull, named Ouwan, to stimulate typical mating behaviours.

Thomas Hildebrandt, the project head of BioRescue, described the process as “uncharted territory,” with the procedures, protocols, methods and equipment developed from scratch.

Unfortunately for the rescue project, both Curra and Ouwan were found dead in November. It’s believed the pair fell ill due to a severe bacterial infection following extremely heavy and climate change-related rains, which flooded the surrogate enclosure.

However, it was revealed at the time that Curra was pregnant with a 70-day-old male fetus. Tissue taken from the fetus confirmed that the pregnancy was a result of the embryo transfer.

Scientists said the next steps of this research program will be to select a new southern white rhino surrogate mother and teaser bull. They will then develop a northern white rhino embryo to implant in the surrogate.

Hildebrandt said they hope the offspring would then be able to live with Najin and Fatu to learn the behaviors of the northern white rhino species.

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