Scientists in the BioRescue research team have successfully impregnated a southern white rhino using a method that can save its critically endangered northern cousin from extinction—only 2 northern white rhinos left in the world, both females.  In a groundbreaking development, researchers have successfully achieved an in vitro fertilization (IVF) pregnancy for rhinos.

The last male northern white rhino, Sudan, died in 2018 and the disappearance of the species looked forthcoming. Fatu and Najin the only two infertile female northern white rhinos are under 24-hour armed protection at the conservation reservation in Kenya. However, a ray of hope to save the species from complete extinction.

The BioRescue Project, a non-profit organization dedicated to reproductive technology for the preservation of endangered species, revealed on Wednesday that they have accomplished the “world’s first successful embryo transfer in rhinos.” This milestone, according to the company, marks a significant step forward in the efforts to prevent the extinction of the northern white rhino.

Contrary to conventional methods, the embryo was not implanted directly into one of the remaining northern white rhinos. Instead, a southern white rhino embryo was created and transferred into a surrogate mother of the same species at the conservancy. The embryo transfer took place on September 24, as reported by the BioRescue Project. Subsequent assessments confirmed a pregnancy of 70 days, revealing a well-developed male embryo measuring 6.4 centimeters in length.

“The successful embryo transfer and pregnancy are a proof of concept and allow us to know safely move to the transfer of northern white rhino embryos,” the group said on Facebook, “a cornerstone in the mission to save the northern white rhino from extinction.”