Scientists at the BioRescue project have announced a breakthrough in embryo transfer that could save the northern white rhinoceros from extinction. According to the World Wildlife Federation, two genetically different subspecies exist—the northern and southern white rhino—found in two different regions of Africa. There are only two northern white rhinos left, both of which are female, living under protected housing in Kenya.

The BioRescue team achieved the world’s first rhino pregnancy through in vitro fertilization by implanting a southern white rhino embryo in a surrogate mother named Curra. Although the surrogate mother died after two months due to an unrelated infection, the successful embryo transfer offers proof of concept that this strategy could help save the white rhinos.

Plans are underway to implant a northern white rhino embryo into a southern white rhino surrogate mother. The scientists have used preserved sperm and eggs from the remaining females to make 30 preserved embryos. The BioRescue project has cost millions of dollars, supported by public and private donors. Eventually, the group hopes to reintroduce northern white rhinos into the wild.