The northern white rhinoceros might be taking a step back from the brink of extinction, Mashable reports. It notes that the last male northern white rhino, Sudan, died in 2018, leaving only two northern white rhinos left, both female.
But according to CNN, scientists were able to extract eggs from Fatu and Najin, the remaining female northern white rhinos, and attempted to fertilize those eggs with frozen sperm from dead males. In this way, CNN says they were able to create two viable northern white rhino embryos. According to the research team, which includes researchers from Kenya, Italy, Germany, and elsewhere, both viable embryos were made using eggs from Fatu and sperm from Suni, as the sperm from Saut that was used to try to fertilize Najin's eggs was of poor quality.
"The entire team has been developing and planning these procedures for years," Thomas Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research says in a statement. "Today we achieved an important milestone on a rocky road which allows us to plan the future steps in the rescue program of the northern white rhino."
Last year, researchers from the San Diego Zoo reported that they sequenced the northern white rhino and the southern white rhino genomes. This, they said at the time, could bolster efforts to prevent their extinction.