Researchers say a rhinoceros was impregnated through embryo transfer in the first successful use of a method that could be used to try to save the nearly extinct northern white rhino subspecies. The experiment was conducted with the less endangered southern white rhino subspecies. The researchers created a southern white rhino embryo in a lab from an egg and sperm collected from other rhinos and transferred it into a southern white rhino surrogate mother. Although the mother later died of a bacterial infection due to flooding, researchers say the pregnancy was successful. They say it proves a concept that could be used in northern white rhinos. There are only two of them left in the world, both females that can’t reproduce naturally.